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Breast Cancer Prevention (PDQ®): Prevention - Health Professional Information [NCI] - Overview


Magnitude of Effect: Breast cancer incidence is decreased by 50%, but published study designs may have produced an overestimate.

Study Design: Observational, case-control, and cohort studies.
Internal Validity: Good.
Consistency: Good.
External Validity: Good.

Prophylactic oophorectomy or ovarian ablation: Harms

Based on solid evidence, castration may cause the abrupt onset of menopausal symptoms such as hot flashes, insomnia, anxiety, and depression. Long-term effects include decreased libido, vaginal dryness, and decreased bone mineral density.

Magnitude of Effect: Nearly all women experience some sleep disturbances, mood changes, hot flashes, and bone demineralization, but the severity of these symptoms varies greatly.

Study Design: Case-control, cohort, and observational studies.
Internal Validity: Good.
Consistency: Good.
External Validity: Good.


  1. Collaborative Group on Hormonal Factors in Breast Cancer.: Breast cancer and breastfeeding: collaborative reanalysis of individual data from 47 epidemiological studies in 30 countries, including 50302 women with breast cancer and 96973 women without the disease. Lancet 360 (9328): 187-95, 2002.
  2. Goss PE, Ingle JN, Alés-Martínez JE, et al.: Exemestane for breast-cancer prevention in postmenopausal women. N Engl J Med 364 (25): 2381-91, 2011.
  3. Montgomery LL, Tran KN, Heelan MC, et al.: Issues of regret in women with contralateral prophylactic mastectomies. Ann Surg Oncol 6 (6): 546-52, 1999.

WebMD Public Information from the National Cancer Institute

Last Updated: February 25, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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