July 22, 2008 — Breast self-examination or physical examination does not improve breast cancer survival and may increase biopsies of benign lumps, according to the results of a Cochrane review reported in the July 16 Online First issue of the Cochrane Database of Systematic Reviews.

"Breast self-examination and clinical breast examination have been promoted for many years as general screening methods to diagnose breast cancer at an early stage in order to decrease morbidity and mortality," write Jan Peter Kösters and Peter C. Gøtzsche from the Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark. "The possible benefits and harms remain unclear."

The goal of this review was to assess whether screening for breast cancer by regular self-examination or clinical breast examination lowers mortality and morbidity from breast cancer.

The authors searched the Cochrane Breast Cancer Group Specialised Register, The Cochrane Library, and PubMed through October 2007 looking for randomized clinical trials, including cluster randomized trials. On the basis of the methods of a trial, the reviewers independently decided which trials to include, and disagreements were resolved by discussion. A fixed-effect model with 95% confidence intervals (CIs) was used for intent-to-treat analyses.

Only 2 trials were analyzed; these were large, population-based studies from Russia and Shanghai that enrolled a total of 388,535 women and compared breast self-examination with no intervention. Breast cancer mortality rates did not differ significantly between groups (relative risk [RR], 1.05; 95% CI, 0.90 - 1.24; 587 deaths total).

In the Russian study, there were more cancers in the breast self-examination vs the control group (RR, 1.24; 95% CI, 1.09 - 1.41), but this was not shown in the Shanghai study (RR, 0.97; 95% CI, 0.88 - 1.06).

In the screening group, there were almost twice as many biopsies with benign results vs the control groups (3406 vs 1856; RR, 1.88; 95% CI, 1.77 - 1.99).

There was also 1 large, population-based trial of clinical breast examination combined with breast self-examination, but the intervention was discontinued because of poor compliance with follow-up, preventing the drawing of any conclusions.

Limitations of this review include unavailability of mammography in the Shanghai study and lack of description of statistical methods in any of the studies.

"Data from two large trials do not suggest a beneficial effect of screening by breast self-examination but do suggest increased harm in terms of increased numbers of benign lesions identified and an increased number of biopsies performed," the reviewers write. "At present, screening by breast self-examination or physical examination cannot be recommended.... It is unlikely that additional trials investigating breast self-examination as a single general screening method would be worthwhile."

The authors of the review have disclosed no relevant financial relationships.

Cochrane Database Syst Rev. Published online July 16, 2008.

Clinical Context

Study Highlights

• Researchers examined Cochrane databases and MEDLINE for randomized clinical trials of breast examination performed by either patients or clinicians. Only studies of women without a history of breast cancer were included in the review.
• The main outcome of the study was breast cancer mortality rates. Researchers also examined rates of all-cancer mortality and overall mortality as well as the identification of tumors and the use of surgical interventions.
• 6 trials were identified for possible inclusion, but only 3 were included. Two of these trials were large, population-based, randomized trials of breast self-examination as a general screening method. The other study compared clinical examination of the breast with instruction in breast self-examination. However, this last study was limited by poor compliance and early study discontinuation.
• The 2 trials focused on breast self-examination were based in Russia and Shanghai and included a total of 388,535 women.
• Overall, the use of breast self-examination did not reduce the risk for breast cancer mortality (RR, 1.05).
• Total mortality rate was reported only in the Shanghai trial. Breast self-examination was associated with a significant 10% reduction in total mortality rate, a result which the authors of the current research consider aberrant and not related to the study intervention.
• The Russian study noted a higher rate of breast cancers detected among women who performed breast self-examination, whereas the Shanghai study did not. There was too much heterogeneity to meaningfully examine tumor stage data in the trials, although the types of procedures for breast cancer were similar between the breast self-examination and control groups in the Shanghai study.
• Breast self-examination significantly increased the RR of undergoing breast biopsy (RR, 1.88).
• Data from the study discontinued early suggested that there was limited difference between clinical breast examination and instruction in breast self-examination in the rate of detection of breast cancer.

Pearls for Practice

• A previous review of routine mammography suggested that mammography had a moderate effect in reducing the risk for mortality from breast cancer, but it did not reduce the risk for all cancer-related or overall mortality. In addition, mammography significantly increased the risk for operative procedures on the breast.
• The current review suggests that breast self-examination does not reduce the risk for mortality from breast cancer, but breast self-examination did increase the risk for undergoing breast biopsy.

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