Table 1. Harms of Screening Mammography
Harm | Study Design | Internal Validity | Consistency | Magnitude of Effects | External Validity |
Treatment of insignificant cancers (overdiagnosis, true positives) can result in breast deformity, lymphedema, thromboembolic events, new cancers, or chemotherapy-induced toxicities. | Descriptive population-based, autopsy series and series of mammary reduction specimens | Good | Good | Approximately 33% of breast cancers detected by screening mammograms represent overdiagnosis.[6] | Good |
Additional testing (false-positives) | Descriptive population-based | Good | Good | Estimated to occur in 50% of women screened annually for 10 years, 25% of whom will have biopsies.[7] | Good |
False sense of security, delay in cancer diagnosis (false-negatives) | Descriptive population-based | Good | Good | 6% to 46% of women with invasive cancer will have negative mammograms, especially if young, with dense breasts,[8,9] or with mucinous, lobular, or fast-growing cancers.[10] | Good |
Radiation-induced mutations can cause breast cancer, especially if exposed before age 30 years. Latency is more than 10 years, and the increased risk persists lifelong. | Descriptive population-based | Good | Good | Between 9.9 and 32 breast cancers per 10,000 women exposed to a cumulative dose of 1 Sv. Risk is higher for younger women.[11,12] | Good |
References
- Zahl PH, Strand BH, Maehlen J: Incidence of breast cancer in Norway and Sweden during introduction of nationwide screening: prospective cohort study. BMJ 328 (7445): 921-4, 2004. [PUBMED Abstract]
- Elmore JG, Barton MB, Moceri VM, et al.: Ten-year risk of false positive screening mammograms and clinical breast examinations. N Engl J Med 338 (16): 1089-96, 1998. [PUBMED Abstract]
- Rosenberg RD, Hunt WC, Williamson MR, et al.: Effects of age, breast density, ethnicity, and estrogen replacement therapy on screening mammographic sensitivity and cancer stage at diagnosis: review of 183,134 screening mammograms in Albuquerque, New Mexico. Radiology 209 (2): 511-8, 1998. [PUBMED Abstract]
- Kerlikowske K, Grady D, Barclay J, et al.: Likelihood ratios for modern screening mammography. Risk of breast cancer based on age and mammographic interpretation. JAMA 276 (1): 39-43, 1996. [PUBMED Abstract]
- Porter PL, El-Bastawissi AY, Mandelson MT, et al.: Breast tumor characteristics as predictors of mammographic detection: comparison of interval- and screen-detected cancers. J Natl Cancer Inst 91 (23): 2020-8, 1999. [PUBMED Abstract]
- Ronckers CM, Erdmann CA, Land CE: Radiation and breast cancer: a review of current evidence. Breast Cancer Res 7 (1): 21-32, 2005. [PUBMED Abstract]
- Goss PE, Sierra S: Current perspectives on radiation-induced breast cancer. J Clin Oncol 16 (1): 338-47, 1998. [PUBMED Abstract]