Breast cancer

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Breast cancer at a glance

Breast cancer begins when cells in breast tissue grow in an uncontrolled way. Treatment depends on how far the cancer has grown or spread and on tests performed on the cancer cells. These include tests for oestrogen receptors (ER), progesterone receptors (PR) and human epidermal growth factor receptor 2 (HER2). The results help your team choose medicines that are likely to work.

Many early cancers can be treated with the aim of cure. Cancer that has spread to distant organs is usually treated to control it, prolong life and protect quality of life. Effective treatment may involve several different approaches in a planned order.

This guide focuses on invasive breast cancer in adults: cancer that has grown beyond the ducts or lobules where it began. It also explains ductal carcinoma in situ (DCIS), which stays inside the milk ducts. The guide applies to women and men, although some treatment decisions differ.

A new breast lump is not always cancer, and a scan alone does not usually confirm the diagnosis. If you already have a pathology report, which gives the results of tissue testing, start with three questions: what type of cancer is it, what are the receptor results, and what is the stage?

Symptoms and warning signs

Arrange an assessment for a new lump in the breast or armpit, a nipple that newly turns inward, bloody nipple discharge without squeezing, a persistent change in breast shape, or skin dimpling. Redness, thickening or swelling that does not settle also needs assessment. Pain alone is often caused by something other than cancer, but a persistent new change should be checked. Have new symptoms assessed even if a recent screening mammogram was normal.

Rapid swelling, warmth and redness can sometimes represent inflammatory breast cancer, even without a distinct lump. Infection is another possible cause. If symptoms persist despite initial treatment, return promptly for reassessment. Do not repeatedly treat a continuing breast change without confirming the cause.

Making this information useful to you

You do not need to learn every treatment name at once. Begin with your diagnosis, receptor results, stage and the next recommended step. A relative or friend can join appointments if helpful. Ask for an interpreter if you need one.

Your results, general health and priorities determine which options apply. Ask your team to explain a recommendation that differs from something you have read. Keep a list of medicines, allergies and other health conditions, including vitamins and herbal remedies. Do not stop an established medicine without advice. Bring your most important questions first.

Understand

How breast cancer develops

Breast tissue contains milk-producing lobules and ducts that carry milk towards the nipple. Most breast cancers begin in the cells lining these structures. Invasive ductal cancer is the most common type; your report may call it invasive carcinoma of no special type. Invasive lobular cancer begins in the lobules and can be harder to see on routine breast scans. Both types can spread through lymph vessels, which carry tissue fluid, or through the bloodstream.

DCIS stays inside the milk ducts and has not grown into surrounding breast tissue. It is stage 0. Treatment aims to prevent invasive cancer from developing and to address any invasive cancer that may not have been found in the first sample.

Lobular carcinoma in situ is a different condition. It often signals an increased future risk of breast cancer rather than being an invasive cancer itself. Some forms need specialist advice. Your team can explain which diagnosis appears on your report.

Receptors and what they mean

Receptors are proteins on or inside cells that respond to signals. Testing the cancer cells for ER, PR and HER2 helps identify treatments that may work.

• Hormone receptor positive: the cancer has oestrogen receptors, progesterone receptors, or both. Hormone therapy, also called endocrine treatment, reduces the hormone signals that help it grow.
• HER2 positive: the cancer has too much HER2 protein or extra copies of the HER2 gene on laboratory testing. Medicines that target HER2 may help.
• Triple negative: tests are negative for ER, PR and HER2. Treatment may include chemotherapy and, for suitable patients, immunotherapy, antibody–drug conjugates or other targeted medicines. Immunotherapy helps the immune system attack cancer. Antibody–drug conjugates use an antibody to carry a cancer-killing medicine to cells with a particular feature.
• HER2 low or ultralow: these results describe small amounts of HER2 protein. They may help select certain antibody–drug conjugates for advanced cancer, even though the cancer is classed as HER2 negative for conventional HER2 treatment.

Receptor groups overlap: a cancer can be both hormone receptor positive and HER2 positive. If only a small proportion of cancer cells test positive for ER, the expected benefit of hormone therapy may differ from a strongly positive result. Your team uses the complete pathology report to guide the choice.

Factors that increase risk

Risk increases with age and can be influenced by inherited gene changes, family history, previous chest radiotherapy, reproductive and hormonal factors, alcohol and excess body weight after menopause. Many people diagnosed have no close relative with breast cancer. Having a risk factor does not establish why an individual developed cancer, and a diagnosis is not evidence of personal fault.

Inherited changes, also called mutations, in genes such as BRCA1, BRCA2 or PALB2 may affect treatment, future cancer risk and relatives. Genetic counselling helps explain what testing may mean for you and your family. Testing for inherited changes is often called germline testing.

It is particularly relevant when breast cancer occurs at a younger age, is triple negative, occurs in a man, or there is a strong family history. It may also help when a result could change treatment. Ask whether testing is suitable even if you have no obvious family history. Testing the tumour and testing for inherited risk answer different questions.

Tests and diagnosis

How cancer is diagnosed

Assessment usually combines examination, breast imaging and a needle biopsy. Mammography, an X-ray of the breast, and ultrasound provide different information. Magnetic resonance imaging (MRI) gives detailed images and may help when the extent of cancer is unclear, with some lobular cancers, with a high inherited risk, or when planning treatment. It is not needed for everyone. A suspicious lymph node in the armpit may also be sampled.

A core needle biopsy removes small pieces of tissue for diagnosis and receptor tests. Fine-needle aspiration cytology (FNAC) samples individual cells and is generally avoided as the main test for a suspicious breast lump when a core biopsy can be performed safely. Core biopsy gives more information about the tissue structure and whether cancer is invasive. Fine-needle sampling may still be useful for some lymph nodes or fluid-filled cysts.

If treatment is planned before surgery, a small marker clip may be placed in the tumour and sometimes in a sampled lymph node. This helps the surgeon find the original site if the cancer shrinks. Tell the team about breast implants, previous operations and earlier scans. Ask whether any other suspicious areas need assessment before choosing an operation.

Understanding your pathology report

The pathology report describes the cancer type, grade and results for ER, PR and HER2. Grade describes how abnormal the cells look under a microscope and helps estimate how quickly they may grow. Stage describes the size and spread of the cancer.

HER2 testing may require an additional gene-based test, such as fluorescence in situ hybridisation (FISH), when the initial result is uncertain. This checks whether the cancer cells have extra copies of the HER2 gene. A second review or repeat test may help if the sample is too small or the results do not fit the other findings.

After surgery, the report also describes the tumour size, the edges of the removed tissue (margins), lymph nodes and any response to treatment given before surgery. A clear margin means no cancer is seen at the cut edge; your surgeon will explain how much clearance is needed for your type of cancer.

Cancer that remains after treatment is called residual cancer. Finding residual cancer after treatment before surgery may change the next treatment choice. It does not automatically mean that the earlier treatment gave no benefit.

Scans and staging tests

Staging establishes how far breast cancer has spread and helps your team plan treatment. At CTI, staging scans are commonly used as part of this assessment. Depending on the clinical findings, these may include computed tomography (CT) scans of the chest and abdomen with a bone scan when needed, or positron emission tomography combined with CT (PET-CT). These are established staging investigations; your oncologist selects the appropriate tests based on the confirmed diagnosis, tumour and lymph-node findings, symptoms and planned treatment.

Blood tests help assess general health and treatment safety but do not replace a biopsy. A suspicious finding in a distant organ may need a biopsy before changing the aim of treatment.

Cancer in nearby lymph nodes is not the same as stage 4 (IV). The next section explains how the stage is worked out.

Testing cancer that has returned or spread

If cancer is suspected to have returned in a distant part of the body, a biopsy can confirm the diagnosis and recheck ER, PR and HER2, because these results can change. Molecular testing in advanced disease looks for changes in genes such as ESR1, PIK3CA, AKT1 and PTEN that may guide treatment.

Other tests may help guide immunotherapy:

• Programmed death-ligand 1 (PD-L1): a protein tested to help select some immunotherapy treatments.
• Mismatch repair (MMR) and microsatellite instability (MSI): tests for problems with how cancer cells repair errors in DNA, the genetic material in cells.
• Tumour mutational burden (TMB): a measure of how many gene changes are found in the cancer.

Your team selects the tests relevant to your cancer and treatment history.

When a gene-based test helps with chemotherapy decisions

For some hormone receptor positive, HER2-negative early cancers, a test of several genes in the tumour can help estimate whether adding chemotherapy to hormone therapy would be useful. This is called a multigene recurrence assay; recurrence means cancer returning. It is different from testing for an inherited cancer risk.

Whether the test is useful depends on whether you have reached menopause, any lymph-node involvement and other cancer features. It is not needed for everyone and does not guide chemotherapy decisions for every breast cancer type.

Preparing for your appointment

For your consultation or a second opinion, bring a compact disc (CD) containing your scan images in Digital Imaging and Communications in Medicine (DICOM) format and the software needed to view them, along with the written scan reports.

Bring your biopsy report and ask whether the laboratory slides or stored tissue samples are needed for review or more tests. Keep originals safe and agree how borrowed material will be returned. If a test needs repeating, ask what it will clarify, how it may affect treatment and when to expect the result.

Before a scan or procedure, mention kidney problems, previous reactions to scan contrast, implanted devices, diabetes medicines, blood-thinning medicines and possible pregnancy. Follow the testing centre’s instructions about food, drink and medicines. Contact the centre if you have not received them.

Planning your treatment

Understanding your stage

Anatomical and prognostic staging for breast cancer

Your report may describe an anatomical stage, based on the size and spread of the cancer, and a prognostic stage, which also considers grade, ER, PR and HER2 results and sometimes a gene test. These can differ. The illustrations below show anatomical stages.

Lymph nodes are small immune-system structures. Regional nodes are those near or draining the cancer’s starting area; distant spread means cancer has reached a site outside that regional area. Stages describe findings, not a sequence that everyone will pass through.

Purple represents cancer. Each picture shows one possible example of an anatomical stage.

Stage 0

Ductal carcinoma in situ (DCIS) remains inside the breast ducts. It has not grown into surrounding breast tissue or spread to distant organs.

Stage 1 (I)

There is a small invasive tumour, usually no larger than 2 cm, with no regional node involvement or only a very small amount in a node.

Stage 2 (II)

The tumour is larger, or there is a limited amount of regional lymph-node involvement, or both. It has not reached distant organs.

Stage 3 (III)

There is more extensive involvement of nearby lymph nodes, or growth into the skin or chest wall, without distant spread. Inflammatory breast cancer is stage 3 unless distant spread is present.

Stage 4 (IV)

Breast cancer cells have reached distant sites such as bone, liver, lung or brain. A tumour in the opposite breast may be a separate primary cancer and needs assessment.

Cancer in nearby lymph nodes can sometimes have a lower prognostic stage because receptor results and grade also matter. Stage alone does not decide treatment. Your team can explain how the size, spread and test results fit together.

Clinical stage is based on examinations, biopsies and scans. Examining tissue removed during surgery can add information, called the pathological stage. If your report has the letters yp before the stage, the tissue was assessed after treatment. A more complete assessment does not necessarily mean the cancer has grown while you were waiting.

How your treatment plan is chosen

For early breast cancer, a multidisciplinary team brings breast specialists together to plan surgery, radiotherapy and medicines. The plan takes account of the stage, receptor results, whether you have reached menopause, your general health and your preferences.

Treatment before surgery is called neoadjuvant treatment. It can shrink a cancer, make surgery easier and show how the cancer responds. Treatment after surgery is called adjuvant treatment and aims to reduce the chance of cancer returning.

For many people with early breast cancer, removing the cancer while keeping the breast, followed by radiotherapy, offers a similar chance of survival to removing the whole breast. The choice depends on the size and location of the cancer, whether there is more than one area, inherited risk, previous radiotherapy and your preferences. Removing more breast tissue is not automatically a better cancer treatment.

Breast reconstruction rebuilds the breast shape. It can be done when the breast is removed (mastectomy) or later. You can also choose a flat chest after surgery or an external breast form worn inside a bra.

Questions specific to breast cancer

Ask whether medicines should come before surgery, whether it is possible to keep the breast, and whether lymph nodes in the armpit need treatment. Discuss the expected benefit of each medicine. Ask about fertility before chemotherapy or long-term hormone therapy. If you are pregnant, cancer specialists and your pregnancy-care team need to plan treatment together because safety changes during pregnancy.

Questions to ask your care team

• What is the exact cancer type and stage, and are any important results still pending?
• Is the aim to cure the cancer, reduce the chance of recurrence, control it, or relieve a particular symptom?
• What benefit do you expect from this option, and what are the reasonable alternatives for me?
• How will treatment affect everyday activities, fertility, sexual health and the things I most value?
• How will we know whether it is working, and when will we review the plan?
• Who should I contact between visits, including at night or over a weekend?

Clinical trials and newer treatments

A clinical trial can be worth considering at diagnosis or when treatment needs to change. Trials ask a defined question; some compare established treatments and others study a newer approach. Eligibility depends on the cancer, previous treatment, test results and health. Taking part is voluntary, and choosing not to participate does not remove your right to standard care. Ask about extra visits, whether treatment is assigned by chance (randomisation), costs, travel, side effects and what happens when the study ends.

Newer treatments are considered using the clinical evidence, recognised guidelines and the exact cancer type, biomarkers and previous treatment. For some newer options, less is known about their long-term benefits and risks. Ask what is known, what remains uncertain and whether a clinical trial would be appropriate.

Your priorities and supportive care

Tell the team what you are hoping treatment will make possible: returning to work, caring for family, keeping independence, reducing pain or attending an important event. These priorities can influence a choice between reasonable options. If treatment is likely to offer little benefit but cause considerable difficulty, you can discuss a less intensive approach. Decisions can be revisited when your health or circumstances change.

Supportive and palliative care help with symptoms, sleep, mood, family concerns and planning. They can be provided alongside treatment intended to cure or control cancer. A referral does not mean that active treatment is ending. If the cancer cannot be cured, ask what treatments may help you live longer or more comfortably and how their burdens compare with their likely benefits.

Treatment options

Early breast cancer

The options below cover breast cancer that has not spread to distant organs, including cancer that has grown more extensively in the breast, nearby tissues or lymph nodes (locally advanced breast cancer). Your team will explain which treatments apply to you and the order in which they are given.

Surgery and lymph node treatment

A lumpectomy removes the cancer with surrounding tissue while preserving the breast. Mastectomy removes most breast tissue and may preserve skin or the nipple in selected circumstances.

A second operation is sometimes needed if cancer remains at the edge of the removed tissue, called the margin. Where frozen-section testing is available and suitable, the pathologist can check the margins during surgery so the surgeon can remove more tissue in the same operation if needed. This may avoid a second operation, although the final laboratory report can still show that further surgery is needed.

After either operation, you may also need medicines that reach cancer cells throughout the body, called systemic treatment. Radiotherapy may still be needed after mastectomy if it would help reduce the risk of cancer returning.

A sentinel lymph node biopsy checks the first lymph nodes that receive fluid from the breast. Some carefully selected patients may not need lymph-node surgery. Others may need more nodes removed or treated.

Finding cancer in a sentinel node does not always mean that many armpit nodes need to be removed, an operation called axillary clearance. The decision depends on the amount of cancer in the nodes, the breast operation, planned radiotherapy and any treatment already given. Ask how the team balances cancer control with the risk of long-term arm swelling (lymphoedema) and shoulder problems.

Radiotherapy

Radiotherapy reduces the chance of cancer returning in the treated area. It is usually used after breast-conserving surgery and sometimes after mastectomy. The number of sessions depends on the area being treated and your circumstances. Some people at lower risk may be able to have radiotherapy to part of the breast or discuss leaving it out. For left-sided breast cancer, holding your breath during treatment may help keep radiation away from the heart.

Temporary skin soreness and tiredness are common. Less common effects can involve the breast tissue, ribs, lung or heart. Treatment planning is individual, particularly after reconstruction. Ask which areas will be treated, whether an extra dose to the original tumour area (a boost) is needed, and how to care for your skin. Radiotherapy to the breast does not make you radioactive.

Hormone receptor positive, HER2-negative early cancer

Endocrine treatment, also called hormone therapy, blocks the hormone signals that help the cancer grow. Tamoxifen can be used before or after menopause. Aromatase inhibitors reduce oestrogen production. They are used after menopause, or together with effective ovarian suppression before menopause. Ovarian suppression reduces oestrogen production by the ovaries and may be recommended for selected patients.

It can be achieved with regular injections of a gonadotropin-releasing hormone (GnRH) agonist, such as goserelin, or with an operation to remove both ovaries (bilateral oophorectomy). Injections are intended to suppress ovarian function temporarily; surgery causes permanent menopause and loss of fertility. Discuss these effects and any fertility plans before treatment.

Endocrine treatment commonly continues for several years, with its duration tailored to the risk of cancer returning, side effects and your preferences.

Chemotherapy may be added when its expected benefit outweighs its side effects and other burdens. Some people at higher risk may also receive abemaciclib or ribociclib after surgery. These are cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors, which block signals that help cancer cells divide.

Some people with an inherited BRCA1 or BRCA2 change and high-risk HER2-negative cancer may benefit from olaparib after standard treatment. These additional medicines have different eligibility requirements and are not needed for every hormone-sensitive cancer.

HER2-positive early cancer

Chemotherapy is often combined with medicines that target HER2. Larger cancers or cancers involving lymph nodes commonly receive treatment before surgery. Some small cancers are removed first. Heart function is checked because certain HER2 treatments can affect it.

Trastuzumab and pertuzumab are established medicines. If invasive cancer remains after treatment before surgery, this may change which medicine is recommended afterwards.

Newer treatment options include trastuzumab deruxtecan in specific situations:

• Before surgery: for selected stage 2–3 HER2-positive cancers, trastuzumab deruxtecan may be followed by a taxane chemotherapy medicine together with trastuzumab and pertuzumab.
• After surgery: trastuzumab deruxtecan may be an option when invasive cancer remains after particular treatments given before surgery.

Your team will check whether you meet the treatment criteria and discuss possible lung inflammation and alternatives. The same combination is not suitable for every early HER2-positive cancer.

Triple-negative early cancer

Chemotherapy is important for many invasive triple-negative cancers. For suitable patients with higher-risk early cancer, pembrolizumab is given with chemotherapy before surgery and continued afterwards as planned. In early breast cancer, its use does not depend on the PD-L1 score used to select treatment for metastatic cancer. Small cancers at lower risk may need a different approach.

If cancer remains after treatment given before surgery, the team will review further options. These may include capecitabine, continuing planned pembrolizumab, or olaparib for eligible patients with an inherited BRCA1 or BRCA2 change. The choice depends on previous treatment and the evidence for your situation. Using every available medicine, together or one after another, is not automatically more helpful.

DCIS and uncommon situations

DCIS is generally treated with surgery. Radiotherapy is often given afterwards if the breast has been kept. Hormone therapy may help reduce future risk when DCIS is hormone sensitive. Chemotherapy is not routinely used for DCIS.

Inflammatory breast cancer usually needs medicines first, followed by surgery and radiotherapy if it has not spread to distant organs. Breast cancer in men follows the same main treatment principles, with particular attention to hormone therapy and inherited-risk testing.

Treatment when cancer has spread

When breast cancer has spread to distant organs, it is called metastatic breast cancer. Treatment usually aims to control the cancer, help you live longer and maintain quality of life. The choice depends on current receptor and molecular test results, symptoms and previous treatment.

Removing the breast cancer is not routinely expected to prolong life when cancer has already spread to distant organs. Surgery or radiotherapy can still help symptoms or selected situations. If cancer has spread to bone, bone-strengthening medicines and radiotherapy may reduce pain and the risk of complications. Dental checks and calcium monitoring may be needed.

Hormone receptor positive, HER2-negative advanced cancer

For hormone receptor positive, HER2-negative cancer, hormone therapy with a CDK4/6 inhibitor is often suitable. If cancer is severely affecting the function of an organ, more urgent treatment may be needed. Spread to an organ such as the liver or lung does not, by itself, mean that chemotherapy is the only option.

Later treatment depends on previous medicines, side effects and tests such as ESR1, PIK3CA, AKT1, PTEN and inherited BRCA1 or BRCA2 testing. Chemotherapy or an antibody–drug conjugate may be considered when hormone therapy is no longer controlling the cancer well.

For advanced hormone receptor positive, HER2-negative cancer, molecular test results can help guide further treatment:

• Imlunestrant with abemaciclib: an option for ER-positive cancer with an ESR1 mutation that has worsened after endocrine treatment.
• Camizestrant with a CDK4/6 inhibitor: an option when an ESR1 mutation is detected during treatment with an aromatase inhibitor and a CDK4/6 inhibitor. This means switching the hormone medicine while continuing the CDK4/6 inhibitor. It is a specific approach for advanced cancer, not a reason to start treatment for an abnormal blood test in early breast cancer.
• Vepdegestrant: another option for ER-positive, HER2-negative advanced cancer with an ESR1 mutation that has worsened after at least one line of endocrine treatment.
• Gedatolisib with fulvestrant, with or without palbociclib: an option for hormone receptor positive, HER2-negative advanced cancer without a detected PIK3CA mutation that has worsened during or after at least one line of endocrine treatment for metastatic disease.

These options have different requirements. Your oncologist will explain which, if any, fits your results and treatment history.

Capivasertib blocks protein kinase B (AKT), which carries growth signals inside cancer cells. It is called an AKT inhibitor. With fulvestrant, it is an option for adults with hormone receptor positive, HER2-negative locally advanced or metastatic cancer whose tumour has a PIK3CA, AKT1 or PTEN alteration. It is used after progression on endocrine treatment for metastatic disease, or when cancer returns during or within 12 months of completing endocrine treatment after surgery.

HER2-positive advanced cancer

HER2-positive metastatic cancer is treated with medicines that target HER2. Trastuzumab deruxtecan with pertuzumab is a first-line option, meaning an initial treatment for metastatic cancer, for eligible patients. Another established approach starts with a taxane chemotherapy medicine and trastuzumab, with or without pertuzumab. The choice depends on previous treatment, whether the brain is involved, possible side effects and your overall health.

Maintenance after taxane-based HER2 treatment

Maintenance treatment aims to keep advanced HER2-positive cancer controlled after the initial chemotherapy has finished. These options are for adults whose cancer has not worsened during that treatment.

How hormone receptor results affect the choice

• Hormone receptor positive, HER2 positive: a PATINA-based plan is an option. Tucatinib with trastuzumab and pertuzumab is also an option for suitable patients in this group.
• Hormone receptor negative, HER2 positive: tucatinib with trastuzumab and pertuzumab is an option. The PATINA plan does not apply because it includes hormone therapy.

The PATINA plan: palbociclib with hormone and HER2 treatment

Palbociclib is added to hormone therapy and trastuzumab, with or without pertuzumab. This FDA-approved option follows initial taxane chemotherapy with trastuzumab, with or without pertuzumab. It is specifically for hormone receptor positive cancer. Palbociclib can lower white blood cell counts, so regular blood tests are needed.

The HER2CLIMB-05 plan: tucatinib with trastuzumab and pertuzumab

Tucatinib tablets are added while trastuzumab and pertuzumab continue. This became an FDA-approved standard maintenance option on 7 October 2026 for HER2-positive cancer that has spread or is locally advanced and cannot be removed by surgery. It applies to either hormone receptor group. People with hormone receptor positive cancer may also continue hormone therapy.

The trial studied people whose cancer had not worsened after four to eight cycles of a taxane with trastuzumab and pertuzumab. Adding tucatinib delayed cancer growth compared with continuing trastuzumab and pertuzumab alone. Whether it helps people live longer is not yet established. Diarrhoea and liver injury can occur, so regular liver blood tests are needed.

Choosing between the plans

The trials did not compare palbociclib with tucatinib, so they cannot tell us which plan is better for someone eligible for both. The choice also depends on previous treatment, side effects, other health conditions and your preferences. Neither trial tested these maintenance plans after trastuzumab deruxtecan.

Triple-negative advanced cancer

Treatment for triple-negative breast cancer that has spread may include chemotherapy, immunotherapy, an antibody–drug conjugate, or a poly(ADP-ribose) polymerase (PARP) inhibitor for eligible patients with an inherited BRCA1 or BRCA2 change. PARP inhibitors are targeted medicines that interfere with cancer cells’ ability to repair damage to their DNA. Whether immunotherapy is suitable depends on test results, such as PD-L1, and the treatments you have already received.

Sacituzumab govitecan is a first-line option for triple-negative cancer that has spread, or is locally advanced and cannot be removed by surgery. It can be given with pembrolizumab when the PD-L1 combined positive score (CPS) is at least 10, or alone when immunotherapy targeting programmed cell death protein 1 (PD-1) or PD-L1 is unsuitable.

Datopotamab deruxtecan is also an option for triple-negative cancer in patients who are unsuitable for those immunotherapies. Your team will compare the options and explain which fits your situation; these medicines are not routinely combined.

Antibody–drug conjugates and treatment sequence

Antibody–drug conjugates deliver medicine to cells with a particular surface feature, but can still cause side effects elsewhere in the body.

Trastuzumab deruxtecan may be an option for selected advanced HER2-low or ultralow cancers. Suitability depends on the precise HER2 result, hormone receptors and previous endocrine treatment or chemotherapy. A HER2-negative result that rules out conventional trastuzumab does not always rule out this separate treatment.

Sacituzumab govitecan and datopotamab deruxtecan both target a cell-surface protein called trophoblast cell-surface antigen 2 (TROP2), but they have different evidence and treatment criteria. A response to one does not prove that the other will work if the cancer later grows.

The order of treatment depends on previous medicines, possible lung inflammation, blood counts, mouth or eye problems, diarrhoea and your treatment goals. Ask whether a new biopsy or another review of the HER2 test would help guide the choice.

Managing side effects

Breast, arm and shoulder recovery

Follow the surgical team’s advice on wound care, drains and gradually restoring shoulder movement. Contact the team if you develop increasing redness, fever, swelling or discharge.

Persistent arm or breast swelling may be lymphoedema, caused by a build-up of lymph fluid. Early assessment, suitable exercise and compression garments may help. Sudden painful arm swelling needs urgent assessment because it may be caused by a clot or infection.

Endocrine and targeted treatment effects

Hot flushes, joint discomfort, vaginal dryness and changes in sexual wellbeing can make it difficult to keep taking hormone therapy. Tell the team if you are struggling; symptom treatment or a change of medicine may help. Bone protection is explained under Live well. Tamoxifen increases the risk of blood clots, and any unexpected vaginal bleeding needs assessment. Discuss hormone-containing treatments for symptoms with your team before using them.

• CDK4/6 inhibitors: may cause low blood counts, diarrhoea or liver problems. Monitoring depends on the medicine.
• HER2-directed medicines: some require regular heart checks.
• Antibody–drug conjugates: may cause nausea, low blood counts and sometimes serious lung inflammation. New cough, breathlessness or fever during trastuzumab deruxtecan treatment needs prompt contact with the team; do not wait for the next cycle.
• Pembrolizumab: can cause inflammation in several organs during or after treatment.

Keeping treatment manageable

Keep the team's contact details available and know where to go outside clinic hours. Report side effects early rather than waiting until the next appointment. A short record of symptoms, temperature, fluid intake and medicines can help the team decide what is needed. Do not change cancer medicine doses, restart a stopped treatment, or use leftover antibiotics without instructions. A planned delay or dose adjustment can be an important part of safe treatment.

If you receive treatment that can lower white blood cells, a temperature of 38°C (100.4°F) or higher needs urgent advice. Follow any lower threshold or additional instructions your team gives you. Chills, sudden weakness, confusion or feeling very unwell also need urgent assessment, even without a fever. Do not wait for a blood test appointment or try to hide the fever with medicine before speaking to the team.

Severe breathlessness, chest pain, a new seizure, sudden weakness, heavy bleeding or collapse require emergency care. New severe back pain with leg weakness, numbness around the bottom, or loss of bladder or bowel control also needs immediate assessment. Contact the nearest emergency service when necessary; a website contact form or routine messaging service is not an emergency pathway.

Eating, drinking and energy

Treatment may change appetite, taste, bowel habits and energy. Small, frequent meals and foods containing protein can be easier than large meals. Ask for help from a dietitian, a specialist in food and nutrition, if you are losing weight, finding it hard to swallow, or avoiding many foods. There is no single diet that treats cancer, and severe restriction or prolonged fasting can make it harder to tolerate treatment. Check supplements with your team because some interact with medicines.

Take anti-sickness medicine as prescribed and report vomiting that prevents you keeping down fluids or essential medicines. Seek advice for persistent diarrhoea, dizziness, very little urine or increasing weakness. Fluid recommendations may need adjustment if you have heart or kidney disease. Mouth ulcers, pain or infection that interferes with eating should be treated promptly rather than accepted as unavoidable.

Gentle movement, short walks and planned rest may help fatigue, but activity should match your condition and any surgical or bone-safety restrictions. Tiredness can also be caused by a low red blood cell count (anaemia), infection, hormone changes, pain, poor sleep or low mood. Let the team assess a marked or persistent change. Accepting help with shopping, transport or meals can conserve energy for the activities that matter to you.

Live well

Protecting your bones during hormone therapy

Aromatase inhibitors and ovarian suppression can weaken bones and increase the risk of fractures. Your team may arrange a bone-density scan called dual-energy X-ray absorptiometry (DXA) before treatment and repeat it, usually every one to two years according to your risk. This is different from a bone scan used to look for cancer spread.

Aim for adequate calcium and vitamin D. Calcium supplements are useful when food does not provide enough; your team can advise on calcium and vitamin D supplements and the right amounts for you. Weight-bearing activity, such as walking, and appropriate strengthening exercises also help protect bone health.

A bisphosphonate is a medicine that helps protect bones. It may be recommended if your bone density is low or your risk of fractures is increased. Some patients who have reached menopause, naturally or because of treatment, may also be offered a bisphosphonate to reduce the risk of breast cancer returning.

The reason for treatment and its schedule differ from those used when cancer has spread to bone. Kidney function, calcium levels and dental health should be checked before treatment.

Follow-up after treatment

Follow-up includes discussing symptoms, examination and breast imaging suited to your operation and remaining breast tissue. Routine whole-body scans or tumour-marker blood tests generally do not help an otherwise well person after treatment for early breast cancer.

Report new persistent bone pain, breathlessness, a breast or chest-wall lump, unexplained weight loss, or new symptoms such as weakness, numbness or changes in balance. Do not wait for your next follow-up appointment. Sudden or severe symptoms need urgent assessment, as described under Managing side effects.

Continue discussions about hormone therapy, bone health, menopausal symptoms, reconstruction and recovery. After both breasts have been removed, routine mammography is usually not needed, but new symptoms still require examination. People with an inherited cancer risk may need extra checks or discussions about reducing future risk.

If you are having treatment for metastatic cancer, your team will arrange scans to assess how well it is controlled. Scan results are considered together with symptoms and side effects.

Emotional and practical support

Feeling frightened, angry, sad or uncertain is understandable. You do not have to appear positive all the time. Ask about counselling, emotional support from a cancer specialist service, support groups or a social worker if worry is affecting sleep, relationships or daily life. Persistent depression, panic or thoughts of self-harm need prompt professional help. Caregivers may need their own support and breaks; one person should not have to manage every appointment and household task alone.

It can help to agree who will update relatives and how much information you want shared. Children usually benefit from honest, age-appropriate explanations and reassurance about who will care for them. Ask permission before discussing private medical information with others. If concentration or memory is difficult, use reminders, a calendar and a trusted companion at important consultations.

Relationships, fertility and sexual health

Cancer and treatment can affect desire, comfort, fertility, body image and confidence. These are valid medical concerns. Raise fertility questions before treatment when possible, because some protective options need to be arranged early. The right approach depends on age, the treatment and how urgently it must start. Do not assume that absent periods or reduced fertility means pregnancy is impossible. Ask about contraception and the safe timing of pregnancy for your specific medicines.

Explain any pain, dryness, erection difficulties or changes in intimacy to the team. Appropriate treatments, rehabilitation and counselling can help. You can choose how much to involve a partner. Advice about hormone-containing treatments needs to take the cancer type and treatment into account; do not start them without discussing suitability.

Planning ahead while living well

Ask for a clear follow-up plan and know which symptoms should be reported between visits. Continue care for other conditions and discuss vaccinations with your oncology team; the timing and suitability of live vaccines can change during treatment. Avoid tobacco and ask for practical cessation support if needed. Activity, food and sleep plans should be realistic for your health rather than another source of pressure.

If treatment is long term, arrange periodic discussions about what is helping, what is difficult and what you want next. Planning for future care can protect your preferences and reduce uncertainty for family. You can discuss who should help with decisions if you become too unwell to speak for yourself, while continuing treatment and everyday life now.

Related care

Explore treatments

Medical Oncology↗Ports, PICCs, and venous access↗Stem Cell Transplant & Cellular Therapy↗Cancer Surgery↗Radiation Oncology↗Cancer Diagnostics & Molecular Testing↗Supportive & Holistic Cancer Care↗

Meet our doctors

Dr (Prof) Vijay Agarwal

Professor and Lead Consultant – Medical Oncology

Dr Prathyush V

Senior Consultant – Medical Oncology & Haemato-Oncology

Dr Darshan R S

Consultant – Medical Oncology & Haemato-Oncology

Where to get care

Bannerghatta Road

Apollo Hospitals
Bengaluru

Seshadripuram

Apollo Hospitals
Bengaluru

Sarjapur

Apollo Hospitals
Bengaluru

Jayanagar

Apollo Speciality Hospital
Bengaluru