ROTTERDAM, The NetherlandsIn the first prospective study of its kind, prophylactic mastectomy prevented the development of breast cancer in women at high risk for breast cancer because of BRCA1/2 mutations, compared with controls who did not opt for surgery.
Researchers at Erasmus University Medical Center, Rotterdam, followed 139 women with a pathogenic BRCA1 or BRCA2 mutation who were enrolled in a breast cancer surveillance program. None of the women had breast cancer at the time of enrollment, and no invasive cancers were found in the women who underwent prophylactic mastectomy (one had lobular carcinoma in situ).
Surveillance included monthly breast self-examination, clinical breast examination every 6 months, and yearly mammography. MRI was offered as an option starting in 1995, and ultrasonography with or without fine-needle aspiration was performed when indicated.
A total of 76 women underwent prophylactic mastectomy, while 63 remained under regular surveillance. After a mean follow-up of 2.9 years, there were no cases of invasive breast cancer in the prophylactic mastectomy group, whereas eight breast cancers developed in the surveillance group (mean follow-up, 3 years) (P = .003), said Hanne Meijers-Heijboer, MD, and colleagues (N Engl J Med 345:159-164, 2001). The researchers noted that the short follow-up calls for a cautious interpretation of the results.
Four cancers were detected between screening sessions, at intervals of 2 to 5 months, and four during a screening session. "In view of the high number of interval cancers, high-resolution imaging and more frequent screening might be useful in women with a BRCA1/2 mutation," Dr. Meijers-Heijboer said.