# Breast cancer (all types)

Source: https://onco.cc/cancers/breast-cancer/  
OnCo record `breast-cancer` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

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.

## Fields

- Kind: Cancer
- Last checked: 2026-09-17
- Also known as: Breast carcinoma; Carcinoma of the breast
- Tags: parent-page
- 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)

## Standard of care

- Screening: Mammography every one to three years from around age 40 to 50 depending on country; MRI for high-risk women. ([Mammography & tomosynthesis](https://onco.cc/technologies/mammography/))
- Early disease, all types: Breast-conserving surgery with radiotherapy or mastectomy, sentinel node biopsy, then treatment by receptor type on the subtype pages. ([HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/), [Hypofractionated radiotherapy](https://onco.cc/technologies/hypofractionated-radiotherapy/))
- Ductal carcinoma in situ: Surgery with or without radiotherapy and endocrine therapy; active surveillance under study. ([Ductal carcinoma in situ (DCIS)](https://onco.cc/cancers/ductal-carcinoma-in-situ/))

## State of the art

- 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.

## Open problems

- 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.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Breast_cancer
- Wikipedia: https://en.wikipedia.org/wiki/Breast_cancer
- NCI PDQ: https://www.cancer.gov/types/breast

## Connected records

- drugs: [Palbociclib](https://onco.cc/drugs/palbociclib/), [Tamoxifen](https://onco.cc/drugs/tamoxifen/), [Trastuzumab](https://onco.cc/drugs/trastuzumab/), [Trastuzumab deruxtecan](https://onco.cc/drugs/trastuzumab-deruxtecan/)
- technologies: [Hypofractionated radiotherapy](https://onco.cc/technologies/hypofractionated-radiotherapy/), [Mammography & tomosynthesis](https://onco.cc/technologies/mammography/)
- cancers: [Ductal carcinoma in situ (DCIS)](https://onco.cc/cancers/ductal-carcinoma-in-situ/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Male breast cancer](https://onco.cc/cancers/male-breast-cancer/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)

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