{"entity":{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","aka":["Breast carcinoma","Carcinoma of the breast"],"tldr":"Breast cancer is not one disease. Which of three receptor patterns the tumour carries decides its treatment: hormone receptor-positive (about 70 percent), HER2-positive (about 15 percent) or triple-negative (about 15 percent). The pages for each type hold the detail; this page holds what they share.","summary":"Breast cancer arises from the milk ducts or lobules and is classified by the receptors on its cells: oestrogen and progesterone receptors, and HER2. Hormone receptor-positive, HER2-negative disease is treated with endocrine therapy and CDK4/6 inhibitors; HER2-positive disease with HER2 antibodies and antibody-drug conjugates; triple-negative disease with chemotherapy, immunotherapy and, for BRCA carriers, PARP inhibitors. Ductal carcinoma in situ is a precursor confined to the duct, and about one percent of cases occur in men. Screening mammography from around age 50, breast-conserving surgery with radiotherapy, sentinel node biopsy and genomic tests that spare chemotherapy are common to all types. Most patients present early and are cured; metastatic disease is treatable for years but rarely curable.","asOf":"2026-09-17","wikipedia":"https://en.wikipedia.org/wiki/Breast_cancer","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Breast_cancer"},{"label":"NCI PDQ","url":"https://www.cancer.gov/types/breast"}],"tags":["parent-page"],"related":[],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"notes":[],"group":"breast","burden":"The commonest cancer worldwide, with about 2.3 million new cases and 670,000 deaths a year; in high-income countries about nine in ten women diagnosed are alive five years later.","subtypes":["HR-positive / HER2-negative breast cancer","HER2-positive breast cancer","Triple-negative breast cancer (TNBC)","Ductal carcinoma in situ (DCIS)","Male breast cancer","Invasive lobular carcinoma","Inflammatory breast cancer"],"biomarkers":["Oestrogen and progesterone receptors","HER2 (including HER2-low)","Ki-67 and grade","Genomic recurrence scores (Oncotype DX, MammaPrint)","BRCA1/2 and other germline variants","PD-L1 (triple-negative)","ESR1 and PIK3CA mutations (advanced hormone receptor-positive)"],"standardOfCare":[{"setting":"Screening","approach":"Mammography every one to three years from around age 40 to 50 depending on country; MRI for high-risk women.","refs":["mammography"]},{"setting":"Early disease, all types","approach":"Breast-conserving surgery with radiotherapy or mastectomy, sentinel node biopsy, then treatment by receptor type on the subtype pages.","refs":["breast-hr-positive","breast-her2-positive","tnbc","hypofractionated-radiotherapy"]},{"setting":"Ductal carcinoma in situ","approach":"Surgery with or without radiotherapy and endocrine therapy; active surveillance under study.","refs":["ductal-carcinoma-in-situ"]}],"stateOfArt":["Five-year survival above 90 percent in early disease across high-income countries, driven by screening, endocrine therapy and HER2-targeted drugs.","Antibody-drug conjugates such as trastuzumab deruxtecan have redrawn the HER2 boundary and moved into HER2-low disease.","Genomic tests spare most node-negative hormone receptor-positive patients chemotherapy.","Omission of radiotherapy in older low-risk women and one-week hypofractionation are reducing treatment burden."],"history":[{"year":1894,"title":"Halsted radical mastectomy","note":"The standard operation for seventy years.","refs":[]},{"year":1977,"title":"Tamoxifen approved","note":"The first targeted hormonal therapy for breast cancer.","refs":["tamoxifen"]},{"year":1985,"title":"NSABP B-06: lumpectomy plus radiotherapy equals mastectomy","refs":[]},{"year":1998,"title":"Trastuzumab approved","note":"The first HER2-targeted antibody.","refs":["trastuzumab"]},{"year":2000,"title":"Molecular subtypes described","note":"Perou and Sorlie's expression profiling defines luminal, HER2-enriched and basal-like breast cancers.","refs":[]},{"year":2015,"title":"CDK4/6 inhibitors approved","refs":["palbociclib"]},{"year":2022,"title":"Trastuzumab deruxtecan in HER2-low disease","refs":["trastuzumab-deruxtecan"]}],"pipeline":[],"openProblems":["Metastatic disease remains incurable for almost everyone.","Triple-negative and inflammatory breast cancer still have the worst outlook.","Overdiagnosis from screening and overtreatment of low-risk DCIS.","Survival gaps between countries and between Black and white women in the same country."]},"route":"/cancers/breast-cancer/","neighbours":{"drug":[{"id":"palbociclib","kind":"drug","name":"Palbociclib","route":"/drugs/palbociclib/"},{"id":"tamoxifen","kind":"drug","name":"Tamoxifen","route":"/drugs/tamoxifen/"},{"id":"trastuzumab","kind":"drug","name":"Trastuzumab","route":"/drugs/trastuzumab/"},{"id":"trastuzumab-deruxtecan","kind":"drug","name":"Trastuzumab deruxtecan","route":"/drugs/trastuzumab-deruxtecan/"}],"technology":[{"id":"hypofractionated-radiotherapy","kind":"technology","name":"Hypofractionated radiotherapy","route":"/technologies/hypofractionated-radiotherapy/"},{"id":"mammography","kind":"technology","name":"Mammography & tomosynthesis","route":"/technologies/mammography/"}],"cancer":[{"id":"ductal-carcinoma-in-situ","kind":"cancer","name":"Ductal carcinoma in situ (DCIS)","route":"/cancers/ductal-carcinoma-in-situ/"},{"id":"breast-her2-positive","kind":"cancer","name":"HER2-positive breast cancer","route":"/cancers/breast-her2-positive/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"male-breast-cancer","kind":"cancer","name":"Male breast cancer","route":"/cancers/male-breast-cancer/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}]}}