Clinical breast examination offers modest benefit to breast cancer screening program

The study of 61,688 women 40 years and older (574 with invasive breast cancer) who participated in a breast cancer screening program at Group Health Cooperative in Seattle, WA, found that mammography plus clinical breast examination detected 470 (82%) of the cancers; mammography detected 445 (78%) of the breast cancers and clinical breast examination detected 121 (21%) of the cancers. "Adding clinical breast examination to screening mammography detected an additional 25 (4%) cancers in the study population," said Nina Oestreicher, PhD, scientist at Kaiser Permanente Division of Research in Oakland, CA. "Given this modest benefit and the current lack of evidence of mortality reduction for early detection of cancers by clinical breast examination alone, it is unlikely that the addition of clinical breast examination to a mammography screening program will result in substantial mortality benefits," she added.

Women with dense breasts experienced the most benefit, but also the most harm from including clinical breast examination in a mammography screening program. They were more than twice as likely to have their cancer detected by clinical breast examination alone, but they were also nearly twice as likely to be told that they might have breast cancer when they really didn't (false positive report), Dr. Oestreicher said. These false positive reports lead to more biopsies, she said.

The study emphasizes that mammography far outperforms clinical breast examination regardless of a patient's age and breast density, said Dr. Oestreicher. Some breast cancer screening programs are considering whether they should include clinical breast examination. This study provides insight as to the "benefits" and "harms" of clinical breast examination, she said. "It is up to a woman and her physician to weigh the tradeoffs of clinical breast examination, depending on her breast density, breast cancer risk and personal preferences," Dr. Oestreicher added.

The study appears in the February 2005 issue of the American Journal of Roentgenology.

A PDF of the full study is available upon request to reporters.