Breast cancer develops when abnormal cells in the breast grow uncontrollably and form tumours. It most commonly begins in the milk ducts or milk-producing lobules of the breast. Cancer cells may invade surrounding breast tissue and can spread to nearby lymph nodes or other organs through a process known as metastasis.[1]
Breast cancer includes several types. Invasive ductal carcinoma begins in the cells lining the milk ducts and is the most common type of breast cancer. Invasive lobular carcinoma begins in the milk-producing lobules. Other forms include inflammatory breast cancer, triple-negative breast cancer and metastatic breast cancer.[2] Although breast cancer predominantly affects women, men can also develop the disease. Approximately 0.5–1% of breast
cancers occur in men.[1]
Global Impact
Breast cancer is one of the most common cancers worldwide and the most commonly diagnosed cancer among women. In 2024, approximately 2.4 million women were diagnosed with breast cancer globally, and an estimated 694,000 deaths occurred due to the disease.[1]
Breast cancer was the most common cancer among women in 164 of 186 countries in 2024. The burden varies considerably across countries, with differences in access to early detection, timely diagnosis and comprehensive treatment contributing to disparities in breast cancer outcomes.[1]
Impact in India
Breast cancer is the most commonly diagnosed cancer among women in India. According to IARC GLOBOCAN 2022 estimates, approximately 192,020 new breast cancer cases occurred in India, representing 13.6% of all new cancer cases in the country.[3]
Among Indian women, breast cancer accounted for approximately 26.6% of all new cancer cases, making it the leading cancer among women. It was also one of the leading causes of cancer-related mortality among women in India.[3]
According to the NCRP, breast cancer showed an increasing incidence trend in India, with the highest burden observed in metropolitan cities. The report projected approximately 205,424 breast cancer cases in 2020, increasing to about 232,832 cases by 2025.[4]
Signs and Symptoms
Early breast cancer may not cause noticeable symptoms. A painless lump or thickening in the breast is one of the most common presenting features. Other signs and symptoms may include:[1]
A breast lump or thickening, often without pain
Change in the size, shape or appearance of the breast
Dimpling, redness, pitting or other changes in the breast skin
Change in the appearance or position of the nipple
Abnormal or bloody nipple discharge
Change in the appearance of the skin surrounding the nipple
Lump or swelling in the underarm.[1]
When breast cancer spreads to other parts of the body, additional symptoms may develop depending on the organs involved. For example, spread to the bones may cause bone pain, while spread to the brain may cause headaches or other neurological symptoms.[1]
Treatment Modalities
Treatment of breast cancer depends on the type and stage of cancer, tumour characteristics, biomarker status, age and overall health of the individual. Most people receive more than one type of treatment.[5]
i. Surgery: Surgery is a major treatment for localized breast cancer. The two main surgical approaches are lumpectomy, in which the tumour and a small amount of surrounding breast tissue are removed, and mastectomy, in which the breast is removed. Nearby lymph nodes may also be examined to determine whether the cancer has spread.[5,6]
ii. Radiation Therapy: Radiation therapy uses high-energy radiation to destroy cancer cells. It is commonly given after breast-conserving surgery and may also be recommended after mastectomy in selected patients to reduce the risk of cancer returning in the breast or chest wall.[5]
iii. Chemotherapy: Chemotherapy uses medicines that destroy or control cancer cells throughout the body. It may be given before surgery to shrink a tumour, after surgery to reduce the risk of recurrence, or for advanced and metastatic breast cancer.[5]
iv. Hormone Therapy: Hormone therapy is used for breast cancers that have estrogen and/or progesterone receptors. It works by reducing hormone production or blocking the effects of hormones that can promote the growth of hormone-sensitive breast cancer cells.[5]
v. Targeted Therapy: Targeted therapies act on specific molecular characteristics of breast cancer cells. They may be used for cancers with particular biomarkers, including HER2-positive breast cancers and some cancers with specific genetic alterations.[5]
vi. Immunotherapy: Immunotherapy helps the immune system recognize and attack cancer cells. It is used for selected breast cancers, particularly certain triple-negative breast cancers.[5]
Early Detection
Breast cancer mortality can be reduced when the disease is detected and treated early. Early detection includes awareness of breast cancer signs and symptoms, timely clinical evaluation of breast abnormalities and appropriate referral for diagnosis and treatment.[1]
Mammography can identify breast cancer before symptoms become apparent and is the principal screening method used for early detection. Screening recommendations vary according to age, individual risk and national guidelines.[1]
References
1. World Health Organization. Breast cancer. Geneva: World Health Organization; 2026 Jul 3. Available from: https://www.who.int/news-room/fact-sheets/detail/breast-cancer
2. National Cancer Institute. Breast cancer types. Bethesda (MD): National Cancer Institute; 2025 Dec 2. Available from: https://www.cancer.gov/types/breast/breast-cancer-types
3. International Agency for Research on Cancer. Global Cancer Observatory: India fact sheet. GLOBOCAN 2022. Lyon: International Agency for Research on Cancer; 2024. Available from: https://gco.iarc.who.int/media/globocan/factsheets/populations/356-india-fact-sheet.pdf
4. Indian Council of Medical Research-National Centre for Disease Informatics and Research (ICMR-NCDIR). Report of National Cancer Registry Programme 2020. Bengaluru: ICMR-NCDIR; 2020. Available from: https://www.ncdirindia.org/All_Reports/Report_2020/resources/NCRP_2020_2012_16.pdf
5. National Cancer Institute. Breast cancer treatment. Bethesda (MD): National Cancer Institute; 2025 Dec 2. Available from: https://www.cancer.gov/types/breast/treatment
6. National Cancer Institute. Breast cancer surgery. Bethesda (MD): National Cancer Institute; Available from: https://www.cancer.gov/types/breast/treatment/surgery