Breast Cancer: One Name, Several Biological Subtypes

Breast cancer is not one uniform disease. Cancers arising in the breast can differ in their receptors, growth rate, appearance and response to treatment. Doctors therefore consider both the cancer's stage and its biological subtype when planning care.

What breast cancer is Breast cancer develops when abnormal cells within breast tissue grow without normal control. These cells may remain within a milk duct or lobule, or invade surrounding breast tissue. Invasive cancer can enter lymphatic channels or blood vessels and spread to lymph nodes or distant organs. Breast cancer can occur in women, men, transgender people and non binary people who have breast tissue. Most breast changes are not cancer, but a new or unexplained change requires appropriate assessment. One name does not mean one disease Breast cancer is an umbrella term covering several diseases with different biological behaviour. Two cancers of the same size can respond differently because their cells use different growth signals. Some cancers depend mainly on oestrogen signalling. Others produce too much HER2 protein or lack all three routinely tested receptors. Tumours can also differ in grade, genetic changes, immune features and sensitivity to chemotherapy. This is why breast cancer treatment is personalised rather than identical for everyone with the same diagnosis. Normal breast structure Breast tissue contains lobules that can make milk and ducts that carry milk towards the nipple. Fatty and fibrous tissue surround these structures and influence the breast's shape and texture. Lymphatic vessels drain fluid towards lymph nodes, particularly those in the armpit. Most breast cancers begin in cells lining a duct or lobule. The exact cell type and whether it has crossed its normal boundary are established by pathology. Normal breasts change over time Breasts can feel different during the menstrual cycle, pregnancy, breastfeeding and menopause. Temporary tenderness, fullness or lumpiness can occur because breast tissue responds to hormones. Breast size and texture can also change with age, weight change and some medicines. Many lumps are benign cysts or fibroadenomas, particularly in younger people. Normal variation does not make every change safe to ignore. The important question is whether something is new, persistent or unusual for that person. In situ and invasive disease Ductal carcinoma in situ, usually called DCIS, consists of abnormal cells contained within breast ducts. DCIS has not invaded surrounding breast tissue and cannot spread to distant organs in its current form. Some DCIS would eventually become invasive, while some might never cause harm during a person's lifetime. Invasive breast cancer has crossed the duct or lobule boundary into surrounding tissue. Invasive disease can potentially spread, although many invasive cancers are diagnosed before distant spread occurs. Common pathological types Most invasive breast cancers are invasive carcinoma of no special type, previously called invasive ductal carcinoma. Invasive lobular carcinoma begins in lobular cells and may grow in a more diffuse pattern. Less common types include tubular, mucinous, medullary pattern and metaplastic cancers. The pathological type provides useful information but does not replace receptor status, grade or stage. A person should not infer prognosis from the word ductal or lobular alone. What receptors are Receptors are proteins that receive signals affecting cell growth and survival. Breast cancer tissue is routinely tested for oestrogen receptor, progesterone receptor and HER2 status. These are shortened to ER, PR and HER2. NICE recommends assessing all three simultaneously when invasive breast cancer is first diagnosed histologically. The results help predict which systemic treatments are likely to work. Oestrogen receptor positive breast cancer ER positive cancer cells contain receptors that can respond to oestrogen related signals. Many ER positive cancers are also PR positive, although the exact combination varies. ER positive disease can often be treated with endocrine therapy that blocks oestrogen signalling or reduces oestrogen production. Examples include tamoxifen, aromatase inhibitors and ovarian suppression in selected people. ER positive cancers are biologically diverse. Some grow slowly, while others have high grade or other features indicating greater risk. Progesterone receptors PR is another hormone receptor measured in invasive breast cancer. PR results add information about tumour biology and hormone receptor signalling. Endocrine treatment decisions are driven principally by ER status, considered with PR and the wider pathological profile. A receptor result should not be interpreted without the laboratory's scoring system and multidisciplinary review. HER2 positive breast cancer HER2 is a protein involved in cell growth signalling. HER2 positive cancers have increased HER2 activity, usually because the HER2 gene is amplified or the protein is overproduced. Historically, HER2 positive cancers often behaved aggressively. Targeted medicines such as trastuzumab have substantially changed outcomes by blocking HER2 driven growth. HER2 positive cancers may also be ER positive or ER negative. HER2 positivity is not automatically a separate mutually exclusive group. Triple negative breast cancer Triple negative breast cancer is negative for ER, PR and HER2 according to validated laboratory criteria. Endocrine therapy and standard HER2 targeted medicines do not work when their relevant targets are absent. Chemotherapy is therefore particularly important for many people with triple negative disease. Immunotherapy, PARP inhibitors or antibody drug conjugates may be appropriate in selected early or advanced settings. Triple negative breast cancer is itself biologically varied rather than one completely uniform subtype. Receptor groups can overlap The common treatment oriented groupings are hormone receptor positive and HER2 negative, HER2 positive with either hormone receptor status, and triple negative. A tumour can be ER positive and HER2 positive at the same time. Such a cancer may receive both endocrine treatment and HER2 targeted treatment if clinically appropriate. Terms such as luminal A, luminal B, HER2 enriched and basal like describe related molecular patterns. These molecular labels are not always identical to routine ER, PR and HER2 categories. Why subtype changes treatment Biological subtype identifies treatment targets and predicts sensitivity to particular medicines. ER positive cancers may respond to endocrine therapy. HER2 positive cancers may respond to HER2 targeted medicines. Triple negative cancers cannot be treated through ER or HER2 targets, so chemotherapy and other selected approaches become more prominent. Subtype therefore helps decide which treatment is useful and which treatment would add toxicity without expected benefit. Why stage still matters Stage describes how much cancer is present and where it has spread. A small cancer confined to the breast has different implications from cancer involving many lymph nodes or distant organs. Stage influences the goals, intensity and sequence of treatment. However, stage alone does not identify which medicines will work. Doctors combine stage with subtype, grade, general health, age, menopausal status and personal preferences. Stage and subtype answer different questions Stage asks where the cancer is and how far it has travelled. Subtype asks which biological signals the cancer uses and which treatments may target them. A small HER2 positive cancer and a small ER positive HER2 negative cancer may need different systemic treatment. Two cancers with the same receptors may need different treatment because their stages differ. Neither stage nor subtype should be interpreted in isolation. Tumour grade Grade describes how abnormal the cancer cells look and how actively they appear to be growing. Grade 1 cells resemble normal breast cells more closely and often grow more slowly. Grade 3 cells look more abnormal and are generally more biologically active. Grade 2 lies between these patterns. Grade is not the same as stage. A small cancer can have a high grade, and a larger cancer can have a lower grade. A breast lump A new breast lump or area of thickening is a common presenting feature. Cancerous lumps are often firm and painless, but these features are not reliable enough for self diagnosis. Breast cancer can be painful, soft, mobile or difficult to feel. Most breast lumps are benign, especially in younger people. An unexplained lump should still be examined, even when it hurts or appeared after a recent normal mammogram. An armpit or chest wall lump A lump in the armpit may be an enlarged lymph node. Lymph nodes commonly enlarge because of infection, vaccination or skin inflammation. Breast cancer can also spread to axillary lymph nodes or occasionally present through an armpit lump. A persistent unexplained lump in the armpit or above the collarbone requires assessment. People who have had mastectomy should report new chest wall, scar or armpit lumps. Changes in breast shape or size A new difference in breast size, contour or shape can occur when a tumour pulls on surrounding tissue. One breast is commonly naturally larger than the other. Concern relates to a new, persistent or progressive change rather than longstanding asymmetry. Swelling can also result from infection, trauma, lymphatic obstruction or hormonal change. Clinical examination and imaging are needed when the cause is uncertain. Skin dimpling and tethering A tumour can pull on fibrous tissue and create dimpling or puckering of the skin. The skin may look indented when the arm is raised or when the breast moves. Thickened skin can develop an orange peel appearance known as peau d'orange. Redness may appear red, purple, darker or less visually obvious on brown or black skin. New skin tethering, diffuse thickening or persistent colour change should be assessed promptly. Nipple inversion Some nipples have always pointed inward and this can be a normal anatomical variation. A nipple can also invert temporarily during breastfeeding or after inflammation. New one sided nipple inversion or a change in nipple direction requires assessment. Cancer is only one possible cause, but the change should not be dismissed without examination. Nipple discharge Nipple discharge can occur during pregnancy and breastfeeding and may persist after feeding stops. Some benign duct conditions and medicines can also cause discharge. Spontaneous discharge from one breast, particularly clear or bloodstained discharge from one duct, requires assessment. Discharge from both breasts only when squeezed is less suggestive of cancer but may still require review. Repeated squeezing can perpetuate discharge and should not replace clinical assessment. Nipple rash and Paget disease A persistent scaly, crusted, sore or ulcerated nipple can occasionally represent Paget disease of the nipple. Paget disease is associated with underlying DCIS or invasive breast cancer. Eczema more commonly affects surrounding skin or both breasts, although appearances can overlap. A unilateral nipple rash that persists despite appropriate treatment requires breast assessment. Do not repeatedly treat an unexplained nipple lesion without reviewing the diagnosis. Breast pain Breast pain is common and is usually not caused by cancer. Cyclical pain may vary with hormonal changes and affect both breasts. Muscle, rib or chest wall pain can feel as though it comes from the breast. Cancer can occasionally cause pain, particularly when there is a lump or skin change. Persistent focal pain or pain associated with another new change should be assessed. Inflammatory breast cancer Inflammatory breast cancer is an uncommon, rapidly developing presentation caused by cancer blocking lymphatic vessels in breast skin. The breast can become swollen, warm, heavy, tender or diffusely red or darkened. Peau d'orange and rapid enlargement may occur without a distinct lump. Mastitis can look similar, especially during breastfeeding. Rapid diffuse breast change requires urgent assessment, particularly outside lactation or when antibiotics do not produce expected improvement. Breast cancer during pregnancy or breastfeeding Breasts normally enlarge and become nodular during pregnancy and breastfeeding. Blocked ducts and mastitis are common and usually benign. Pregnancy does not prevent breast cancer, and a persistent lump should not be attributed automatically to milk production. Ultrasound and biopsy can be performed when clinically indicated during pregnancy. Investigation and treatment require coordination between breast, oncology and maternity teams. Breast cancer in men Men have a small amount of breast tissue and can develop breast cancer. A firm lump behind the nipple, nipple inversion, discharge or ulceration may be presenting features. Because breast cancer is less expected in men, symptoms may be ignored or diagnosed later. The same principles of clinical assessment, imaging, biopsy, receptor testing and staging apply. Most male breast cancers are hormone receptor positive, but each tumour must be tested individually. Screening and symptomatic diagnosis are different pathways Screening looks for breast cancer in people who do not have symptoms. Symptomatic assessment investigates a particular lump, discharge, skin change or other concern. Both pathways may use mammography, but their purpose and subsequent testing differ. A screening appointment is not the correct pathway for investigating a new symptom. Someone with symptoms should contact a GP rather than waiting for routine screening. NHS breast screening in England In England, routine NHS breast screening currently invites women for a first mammogram between ages 50 and 53. Invitations then occur every three years until the person turns 71. Women aged 71 or over can request screening every three years but are not automatically invited. Transgender and non binary people may need to discuss eligibility and invitation arrangements with their GP practice. People at very high inherited risk may follow a different surveillance programme using mammography, MRI or both. What a screening mammogram does A mammogram uses low dose X rays to create images of breast tissue. Screening can find cancers that are too small to feel and can identify suspicious calcifications associated with DCIS. Each breast is compressed briefly to obtain clear images from different angles. Most people screened do not require further tests. An abnormal screening result means further assessment is needed, not that cancer has already been confirmed. Benefits of screening Screening can detect some cancers at an earlier stage. Earlier detection may allow simpler treatment and improves the chance that treatment will be effective. Screening reduces deaths from breast cancer across the invited population. The potential benefit applies before symptoms appear. Individual participation remains a personal choice made after considering benefits and harms. Limitations and harms of screening No screening test detects every breast cancer. Some people are recalled for additional imaging or biopsy and are then found not to have cancer. Screening can detect cancers that would never have caused harm during that person's lifetime. This is called overdiagnosis. Mammography uses a small amount of radiation and can be uncomfortable. A clear screening result does not guarantee that cancer is absent or will not develop before the next invitation. Interval breast cancer An interval cancer is diagnosed after a screening result that did not show cancer and before the next routine screen. The cancer may have developed later, grown rapidly or been difficult to see on the earlier mammogram. Dense breast tissue and tumour biology can affect mammographic visibility. Interval cancer does not mean that symptoms should wait until the next screening round. Any new breast change requires symptomatic assessment regardless of the last mammogram result. Screening detected presentation Screening detected cancers are found before the person notices symptoms. They are often smaller and may be confined to the breast, although this is not guaranteed. Screening also detects DCIS and some slow growing cancers. The diagnostic process still requires additional imaging and biopsy. Screening detection describes how the cancer was found, not its receptor subtype or final prognosis. Symptomatic presentation Symptomatic breast cancer is diagnosed after a person or clinician notices a breast or lymph node change. A symptomatic cancer can still be early and highly treatable. A larger or rapidly changing abnormality may be more likely to have advanced locally, but examination alone cannot establish stage. Prompt presentation and assessment reduce avoidable delay. People should not feel blamed for how or when their cancer was found. Referral from primary care A GP assesses the reported change, duration, menstrual or reproductive context and relevant health problems in the family. The clinician examines both breasts and regional lymph node areas when appropriate. NICE recommends a suspected cancer pathway referral for an unexplained breast lump in someone aged 30 or over. Other suspicious skin, nipple, armpit or breast findings can also justify urgent referral. Urgent referral means cancer must be excluded promptly. It does not mean cancer is the most likely diagnosis. Triple assessment Triple assessment combines clinical assessment, breast imaging and tissue sampling when indicated. It is the standard specialist approach for investigating suspected breast cancer. The three components provide different information and should support one another. When findings disagree, further imaging, repeat biopsy or surgical assessment may be necessary. A reassuring examination alone should not override suspicious imaging or pathology. Clinical assessment The breast clinician asks about the new change, previous breast problems and relevant treatments. They examine breast shape, skin, nipples and any palpable abnormality. Both breasts and lymph node regions may be compared. The clinician records the size, location, mobility and texture of a lump without assuming these features establish its cause. Clinical examination guides imaging but cannot reliably distinguish every benign lesion from cancer. Diagnostic mammography Diagnostic mammography investigates a symptom or abnormal screening finding. It may include additional or magnified views targeted at a particular area. Mammography is particularly useful for detecting masses, architectural distortion and microcalcifications. Dense breast tissue can obscure abnormalities, especially in younger people. The choice of imaging depends on age, pregnancy, breast density and the presenting feature. Breast ultrasound Ultrasound uses sound waves rather than radiation. It can distinguish many fluid filled cysts from solid lesions and assess a palpable area directly. Ultrasound is commonly the first imaging test in younger people and during pregnancy. It is also used to assess lymph nodes and guide needle biopsy. A normal ultrasound does not override a clinically or mammographically suspicious finding. Breast MRI Breast MRI is more sensitive than mammography for some abnormalities but produces more false positive findings. It is not routinely required for every newly diagnosed breast cancer. NICE recommends selected use when disease extent remains unclear, mammographic assessment is difficult or invasive lobular cancer requires sizing before breast conserving surgery. MRI is also used within some very high risk screening programmes. An MRI result must be interpreted with mammography, ultrasound and pathology. Needle biopsy A core needle biopsy removes small cylinders of tissue using a hollow needle. Local anaesthetic is normally used, and imaging guides the needle when the lesion is not easily palpable. Pathologists determine whether the sample is benign, in situ or invasive cancer. They assess tumour type, grade and receptor status when invasive cancer is present. A biopsy does not cause breast cancer to spread through the body. Fine needle aspiration Fine needle aspiration removes cells or fluid using a thinner needle. It can be useful for selected cysts or lymph nodes. Core biopsy usually provides more information about breast architecture and invasion. The breast team chooses the sampling method according to the clinical and imaging findings. Inadequate or discordant samples may need repeating. Pathology and receptor testing The pathology report identifies whether the cancer is invasive and describes its type and grade. ER, PR and HER2 are tested using standardised laboratory methods. HER2 assessment may require an additional gene amplification test when the first result is borderline. The amount of cancer in the biopsy may limit some assessments, so results can occasionally be repeated after surgery. Pathology provides the biological foundation for systemic treatment planning. Lymph node assessment Ultrasound is used to examine lymph nodes in the armpit before treatment. Abnormal looking nodes can be sampled using a needle. If imaging does not show involved nodes, a sentinel lymph node biopsy may be performed during surgery for invasive cancer. The sentinel nodes are the first nodes most likely to receive lymphatic drainage from the tumour. Node involvement influences stage and may change surgery, radiotherapy and systemic treatment. What staging means Staging summarises the cancer's anatomical extent. The TNM system considers tumour size and local extension, regional lymph nodes and distant metastases. Stage 0 commonly refers to in situ disease such as DCIS. Stages I to III describe invasive cancers without confirmed distant spread, ranging from localised to locally advanced disease. Stage IV means that cancer has spread to a distant organ and is also called metastatic or secondary breast cancer. Staging does not require every scan for everyone People with small early cancers and no concerning symptoms may not need whole body scans. Unnecessary scans can expose people to radiation and identify harmless findings that create further uncertainty. CT, bone imaging or PET CT may be used when stage, symptoms or laboratory findings suggest possible distant spread. Local breast imaging and lymph node assessment are separate from distant staging. The multidisciplinary team selects investigations according to the individual's risk and presentation. Multidisciplinary decision making Breast cancer treatment is planned by a multidisciplinary team. This commonly includes breast surgeons, radiologists, pathologists, oncologists and specialist nurses. Geneticists, plastic surgeons, fertility specialists, physiotherapists and palliative care teams may contribute when needed. The team combines stage, subtype, grade, imaging, pathology and the person's health and preferences. A recommendation should be explained through shared decision making rather than presented as an unexplained formula. Treatment can occur before or after surgery Neoadjuvant treatment is given before surgery. It may shrink a tumour, increase breast conservation options and show how the cancer responds to systemic treatment. Adjuvant treatment is given after surgery to reduce the risk of microscopic cancer causing recurrence. The best sequence depends on subtype, stage and treatment goals. Receiving chemotherapy before surgery does not necessarily mean the cancer is incurable. Breast conserving surgery Breast conserving surgery removes the cancer with a surrounding margin while preserving most breast tissue. It is sometimes called wide local excision or lumpectomy. Radiotherapy is usually recommended afterwards to reduce local recurrence risk. Further surgery may be needed when cancer cells reach the specimen margin. Breast conserving treatment can provide cancer control comparable to mastectomy in appropriately selected early cancers. Mastectomy Mastectomy removes most breast tissue. It may be recommended for extensive disease, multiple affected areas, some recurrences or when radiotherapy is unsuitable. Some people choose mastectomy after discussing clinically reasonable alternatives. Mastectomy does not guarantee that chemotherapy or radiotherapy will be unnecessary. Reconstruction can be immediate, delayed or declined according to clinical circumstances and personal preference. Surgery to lymph nodes Sentinel lymph node biopsy samples a small number of first draining nodes. Axillary clearance removes more nodes and is reserved for selected people with confirmed nodal disease. Greater axillary treatment can increase the risk of lymphoedema, numbness and shoulder restriction. Not everyone with cancer cells in a sentinel node requires full clearance. The team considers the size of nodal deposits, breast surgery, radiotherapy and systemic treatment. Radiotherapy Radiotherapy uses targeted ionising radiation to destroy cancer cells remaining in a defined area. It is commonly given after breast conserving surgery. It may also be recommended after mastectomy when local recurrence risk is higher. Regional lymph node areas can be included for selected node positive cancers. Radiotherapy decisions depend on surgical findings and anatomical risk, not receptor status alone. Chemotherapy Chemotherapy circulates through the bloodstream and damages rapidly dividing cancer cells. It may be given before or after surgery, or to control metastatic disease. Chemotherapy is commonly considered for triple negative, HER2 positive and higher risk hormone receptor positive cancers. Some low risk ER positive HER2 negative cancers gain little expected benefit and may safely avoid chemotherapy. Grade, lymph nodes, tumour size, genomic tests and general health can influence the decision. Endocrine therapy Endocrine therapy treats hormone receptor positive breast cancer by reducing or blocking oestrogen signalling. Tamoxifen blocks the oestrogen receptor in breast cells. Aromatase inhibitors reduce oestrogen production after menopause or when combined with ovarian suppression. Treatment may continue for several years because ER positive cancer can recur late. Endocrine therapy does not treat a genuinely ER negative tumour. HER2 targeted treatment HER2 targeted medicines treat cancers with confirmed HER2 positivity. Trastuzumab is a central example and may be combined with chemotherapy and other HER2 directed medicines. Treatment can be given before surgery, after surgery or for metastatic disease. Some HER2 therapies can affect heart function, so cardiac monitoring may be required. HER2 targeted treatment is not useful when a cancer is HER2 negative according to validated testing. Immunotherapy and other targeted medicines Immunotherapy helps the immune system recognise or attack cancer more effectively. It is used for selected triple negative cancers according to stage and biomarker criteria. PARP inhibitors can benefit selected people whose cancers are associated with particular inherited BRCA changes. CDK4/6 inhibitors and other targeted medicines are used in selected hormone receptor positive cancers. These treatments are not interchangeable and require specific biological or clinical indications. Why not everyone receives every treatment Each treatment should offer a realistic benefit that outweighs its risks. A person with ER positive low risk disease may need surgery, radiotherapy and endocrine therapy without chemotherapy. Someone with HER2 positive disease may receive chemotherapy and HER2 targeted therapy. Triple negative disease cannot benefit from endocrine or HER2 targeted treatment when those receptors are absent. Age alone should not decide treatment, but frailty, organ function and personal priorities are clinically relevant. Genomic tests Some ER positive HER2 negative early cancers are assessed using genomic expression tests. These tests analyse patterns of genes active within the tumour. They can help estimate recurrence risk and whether chemotherapy is likely to add meaningful benefit. They do not test whether the person inherited a cancer predisposition gene. Genomic tumour testing and inherited genetic testing answer different questions. Inherited genetic testing A minority of breast cancers are strongly associated with inherited variants such as BRCA1, BRCA2 or PALB2. Testing may be offered according to age, tumour subtype, ancestry, health problems in the family and national eligibility criteria. A positive result can affect surgery, systemic treatment and screening for the person and relatives. Most people diagnosed with breast cancer do not have an identifiable high risk inherited variant. Genetic testing should include counselling about possible personal and family implications. Fertility and ovarian function Chemotherapy and endocrine treatments can reduce fertility or bring forward menopause. People who may want a future pregnancy should receive fertility information before treatment begins where possible. Egg, embryo or ovarian tissue preservation may be considered according to age, treatment urgency and clinical suitability. Ovarian suppression during chemotherapy may help preserve ovarian function in selected people. Fertility discussion should not be omitted because a person is single or has not previously expressed a parenting plan. Breast cancer and pregnancy Treatment during pregnancy depends on gestation, stage and tumour biology. Surgery and some chemotherapy can be used during selected parts of pregnancy. Radiotherapy, endocrine therapy and several targeted treatments are usually delayed until after birth. Ending a pregnancy is not automatically required after a breast cancer diagnosis. Care should be coordinated by breast oncology and specialist maternity teams. Treatment adverse effects Surgery can cause pain, altered sensation, shoulder restriction and lymphoedema risk. Radiotherapy can cause skin reactions, fatigue and later tissue changes. Chemotherapy can cause infection risk, nausea, hair loss, neuropathy and effects on fertility or organs. Endocrine treatment can cause menopausal symptoms, joint pain, clotting risk or bone loss depending on the medicine. Targeted treatments have medicine specific risks requiring monitoring and prompt reporting. Neutropenic sepsis Chemotherapy and some other systemic treatments can reduce infection fighting white blood cells. A serious infection can progress rapidly even when the temperature is not dramatically raised. People receiving systemic anticancer therapy should follow the emergency instructions provided by their oncology team. Fever, shaking chills or sudden illness requires immediate oncology assessment rather than waiting for a routine appointment. Neutropenic sepsis is a medical emergency. Early and locally advanced breast cancer Early breast cancer is confined to the breast, with or without limited regional lymph node involvement. Locally advanced cancer has more extensive breast, skin, chest wall or regional node involvement without confirmed distant spread. Both can be treated with curative intent in many circumstances. Treatment may combine systemic therapy, surgery and radiotherapy. Locally advanced does not mean the same as metastatic. Metastatic breast cancer Metastatic breast cancer has spread to distant organs such as bone, liver, lung or brain. It is generally not considered curable with current treatment, although it is often treatable for prolonged periods. Treatment aims to control cancer, relieve symptoms, preserve function and extend life. Subtype remains important because metastatic ER positive, HER2 positive and triple negative cancers use different treatments. Palliative care can support symptom control alongside active anticancer treatment from an early stage. Possible symptoms of distant spread Persistent focal bone pain can occur with bone metastases but has many common benign causes. Breathlessness, persistent cough, abdominal swelling, jaundice, severe headache or neurological change require assessment. These symptoms do not prove metastatic cancer. People previously treated for breast cancer should use their follow up contact pathway for new persistent concerns. Sudden neurological or breathing symptoms require emergency assessment. Response to treatment provides information Imaging and examination may show whether a cancer shrinks during treatment given before surgery. The surgical specimen shows whether viable cancer remains in the breast or lymph nodes. A complete pathological response is especially informative in some HER2 positive and triple negative cancers. Residual disease can influence additional postoperative treatment. Response is one prognostic factor and does not predict an individual's future with certainty. Prognosis is individual Prognosis depends on stage, subtype, grade, lymph node involvement, treatment response and general health. Modern targeted treatments mean historical outcome figures may not reflect current care. Triple negative or HER2 positive status should not be presented as a predetermined outcome. HER2 positive disease now has effective targeted treatments, while triple negative treatment options continue to expand. Population statistics cannot tell one person exactly what will happen. Follow up after treatment Follow up includes surveillance mammography according to the treatment and national guidance. Routine CT, PET CT or tumour marker testing is not generally used after early breast cancer without concerning symptoms. A written care plan should explain medicines, mammography and how to report possible recurrence or treatment effects. Endocrine and bone health treatment may require continued monitoring. People should not wait for a scheduled appointment when a new persistent symptom develops. Emotional and practical effects Breast cancer can affect body image, sexuality, relationships, employment and family roles. Treatment can create menopause symptoms, fertility concerns and fear of recurrence. Some people grieve breast or nipple loss, while others do not experience reconstruction as important. Psychological support, specialist nursing, rehabilitation and peer support should reflect individual priorities. There is no single correct emotional response to diagnosis or treatment. What this lesson should not be used for This lesson cannot diagnose breast cancer from a lump, skin change or mammogram report. It cannot determine receptor status, stage or prognosis without biopsy and specialist assessment. Do not wait for routine screening when a new breast symptom is present. Do not start, stop or choose cancer treatment based only on a general subtype description. Seek medical assessment for any persistent breast, nipple, chest wall or armpit change that is new or unusual.

Breast cancer is a family of biologically different diseases. Stage describes where cancer is and how far it has spread, while ER, PR and HER2 status identify growth pathways and treatment targets. Screening investigates people without symptoms, whereas a new lump, nipple change, discharge or skin change requires prompt symptomatic triple assessment.