Are breast self-exams or clinical exams effective for screening breast cancer?
Breast self-examination has little or no impact on breast cancer mortality and cannot be recommended for cancer screening (strength of recommendation [SOR]: A, based on a systematic review of high-quality randomized, controlled trials [RCTs]). Clinical breast examination is an important means of averting some deaths from breast cancer, but demands careful attention to technique and thoroughness (SOR: B, extrapolating from a high-quality RCT).
We might better serve our patients by improving our examination skills than by urging self-exams We should inform women who choose to practice breast self-examination that they run a higher risk of having a breast biopsy that does not reveal a cancer and that it is not known whether self-examination reduces a woman's chance of dying from breast cancer. (1) Mammography is neither perfectly sensitive nor universally available, and many women detect breast cancer themselves; it remains important for women to know how their breasts look and feel in order to recognize and report any anomalies. But we might better serve our patients by improving our clinical breast examination skills than by urging them to perform regular self-exams; clinicians who spend 3 minutes per breast and use proper technique (vertical strip search pattern, thoroughness, varying palpation pressure, 3 fingers, circular motion, finger pads) have significantly better sensitivity and specificity than those who do not. (2)
* Evidence summary
Breast cancer is the second leading cause of cancer death among American women; 1 in 8 women will be diagnosed with breast cancer in her lifetime, and 1 in 30 will die of it. (3) Breast cancer screening and mammography have become almost synonymous. But physical examinations by clinicians or women themselves remain important methods of screening to consider.
Breast self-examination is appealing as a patient-centered, inexpensive, noninvasive procedure that empowers women and is universally available. However, a recent Cochrane review found no evidence of benefit from self-screening.
Two large RCTs, conducted in St Petersburg, Russia (122,471 women) and Shanghai, China (266,064 women), were found. Both studies used cluster randomization (by worksite) and involved large numbers of women who were meticulously trained in proper breast self-examination technique and had numerous reinforcement sessions. Study compliance and follow-up were excellent. Outcomes assessment was explicitly blinded in the Shanghai study. Neither trial demonstrated a reduction in breast cancer mortality or improvement in the number or stage of cancers detected during 9 to 11 years of follow-up, but there is evidence for harm: a nearly 2-fold increase in false-positive results, physician visits, and biopsies for benign disease. (4)
No trials comparing screening clinical breast examinations alone to no screening have been reported, but good indirect evidence of efficacy comes from the results of the Canadian National Breast Screening Study-2 (CNBSS-2). (5) A total of 39,405 women aged 50 to 59 years were randomized to screening with clinical exams plus mammography or clinical exams alone. Other large RCTs have shown a consistent benefit to mammography screening for women of this age (in-depth independent reviews of recent criticism of the trials have concluded that their flaws do not negate mammography's efficacy in reducing breast cancer mortality). (3,6) The CNBSS-2 trial showed no mortality advantage when mammography was added to an annual, standardized 10- to 15-minute breast examination, implying that careful, detailed, annual clinical breast examinations may be as effective as a mammography screening program. (3)
Recommendations from others
The US Preventive Services Task Force found insufficient evidence to recommend for or against routine clinical exams alone to screen for breast cancer, or to recommend for or against teaching or performing routine breast self-examination. (3) The Canadian Task Force on Preventive Health Services recommends against teaching self-examination to women aged 40 to 69 years due to "fair evidence of no benefit and good evidence of harm." (7,8)
The American Cancer Society continues to recommend periodic clinical exams, (6) and women who choose to do self-examination should receive instruction and have their technique reviewed during periodic health examinations; it is acceptable for women to choose not to do self-examinations. The American Academy of Family Physicians concludes that the evidence is insufficient to recommend for or against breast self-examination." The American College of Obstetricians and Gynecologists recommends both. (10)
(1.) Thomas DB, Gao DL, Ray RM, et al. Randomized trial of breast self-examination in Shanghai: final results. J Natl Cancer Inst 2002; 94:1445-1457.
(2.) Barton MB, Harris R, Fletcher SW. Th erational clinical examination. Does this patient have breast cancer? The screening clinical breast examination: Should it be done? How? JAMA 1999; 282:1270-1280.
(3.) Humphrey LL, Helfand M, Chan BKS, Woolf SH. Breast cancer screening: a summary of the evidence for the US Preventive Services Task Force. Ann Intern Med 2002; 137:347-360.
(4.) Kosters JP, Gotzsche PC. Regular self-examination or clinical examination for early detection of breast cancer. Cochrane Database Syst Rev 2003; (2):CD003373.
(5.) Miller AB, To T, Baines CJ, Wall C. Canadian National Breast Screening Study-2: 13-year results of a randomized trial in women aged 50-59 years. J Natl Cancer Inst 2000; 92:1490-1499.
(6.) Elmore JG, Armstrong K, Lehman CD, Fletcher SW. Screening for breast cancer. JAMA 2005; 293:1245-1256.
(7.) Baxter N; Canadian Task Force on Preventive Health Care. Preventive health care, 2001 update: Should women be routinely taught breast self-examination to screen for breast cancer? CMAJ 2001; 164:1837-1846.
(8.) Smith RA, Saslow D, Sawyer KA, et al. American Cancer Society guidelines for breast cancer screening: update 2003. CA Cancer J Clin 2003; 53:141-169.
(9.) American Academy of Family Physicians. Summary of Policy Recommendations for Periodic Health Examinations. Revision 5.6, August 2004. Leawood, Kansas: AAFP; 2004.
(10.) American College of Obstetricians and Gynecologists. Breast cancer screening. ACOG practice bulletin No. 42). Washington, DC: ACOG, 2003.
Sean Gaskie, MD
Sutter Family Practice Residency Program, University of California, San Francisco
Joan Nashelsky, MLS
Family Practice Inquiries Network
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|Title Annotation:||CLINICAL INQUIRIES: From the Family Practice Inquiries Network|
|Author:||Gaskie, Sean; Nashelsky, Joan|
|Publication:||Journal of Family Practice|
|Date:||Sep 1, 2005|
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