Breast cancer in situ comprises ductal carcinoma in situ (DCIS), a non-invasive breast cancer that is confined to the duct in which it originates, and lobular carcinoma in situ (LCIS), a neoplastic proliferation of cells that is a risk factor for invasive breast cancer.
Typically asymptomatic and diagnosed at screening.
Breast cancer guideline recommendations differ on when to start screening and screening frequency. In the US, recommendations for bilateral mammography screening in average-risk women range from yearly starting at age 40 years (National Comprehensive Cancer Network) to every 2 years starting at age 50 years (US Preventive Services Task Force). The UK NHS Breast Screening Programme offers routine mammographic screening every 3 years to all women from age 50 years. The UK National Institute for Health and Care Excellence recommends annual mammogram screening from age 40 years in women at moderate risk of breast cancer. The European Society for Medical Oncology recommends annual or biennial mammogram screening in all women from age 50 years.
Diagnosis is with mammography, supplemented with other imaging, such as ultrasound or magnetic resonance imaging, and biopsy.
Chemoprophylaxis (e.g., with tamoxifen, raloxifene, or an aromatase inhibitor [anastrozole or exemestane]) can be used in high-risk patients. Some high-risk patients may choose to undergo preventive bilateral total mastectomy.
Treatment is usually lumpectomy (breast-conserving surgery) followed by radiotherapy.
Breast cancer in situ is a non-invasive breast cancer that is confined to the duct or lobule in which it originated and does not extend beyond the basement membrane. The cancer does not have access to distant spread through lymphatics or the bloodstream. Ductal carcinoma in situ (DCIS) is a potential precursor of invasive carcinoma and suggests that cancer will become invasive at that site.
Lobular carcinoma in situ (LCIS) develops in breast lobule(s) and/or terminal ducts and is usually found incidentally. Whereas DCIS predicts an increased risk of invasive ductal carcinoma developing at the site of a biopsy demonstrating DCIS, LCIS implies increased risk of invasive ductal or lobular carcinoma developing in either breast. LCIS is not cancer but a pathological description of a neoplastic proliferation of cells within lobules and/or terminal ducts, which is a risk factor for invasive breast cancer. A finding of LCIS does not imply that cancer will form at the diagnostic site. Consequently, treatment for LCIS is less formalised than for DCIS.
History and exam
- family history of breast cancer
- benign breast disease on prior biopsy
- hereditary breast ovarian cancer syndrome
- Li-Fraumeni syndrome
- Cowden syndrome
- hereditary diffuse gastric cancer (HDGC)
- Peutz-Jeghers syndrome
- Klinefelter's syndrome
- older age at menopause
- older age at first full-term pregnancy
- low physical activity
- high vitamin A intake
- ataxia telangiectasia
Breast and Gynecologic Cancer Working Group
Division of Cancer Prevention
National Cancer Institute
ERS is an author of a reference cited in this topic.
Dr Edward R. Sauter would like to gratefully acknowledge Dr Rachel L. Ruhlen, a previous contributor to this topic.
Radboud University Nijmegen Medical Centre
CB is an author of a number of references cited in this topic.
Assistant in the Division of Medical Oncology
European Institute of Oncology
AB declares that she has no competing interests.
Associate Professor in Epidemiology and Medical Oncology
Johns Hopkins School of Medicine and Bloomberg School of Public Health
KV is an author of a number of references cited in this topic.
Consultant Surgeon and Honorary Senior Lecturer
Edinburgh Breast Unit
Western General Hospital
GTN is a principal investigator for the IBIS-II trial, and is an author of a guideline cited in this topic.
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