Surveillance of prophylactic mastectomy: trends in use from 1995 through 2005

Background: Prophylactic mastectomy, prophylactic oophorectomy, and antiestrogen chemoprevention are currently the only available methods for breast cancer risk reduction. To the authors' knowledge there is little published information regarding the prevalence of prophylactic mastectomy for the primary prevention of breast cancer among high-risk women or for the prevention of subsequent tumors among women with breast cancer.

Methods: The objective of the current study was to examine the frequency of prophylactic mastectomy in New York State between 1995 and 2005 using mandated statewide discharge data combined with data from the state cancer registry.

Results: Identified were 6275 female residents of New York State receiving prophylactic mastectomy; 19% had no identifiable personal history of breast cancer (including women with lobular carcinoma in situ) and 81% had a personal history of breast cancer (84% with invasive disease and 16% with ductal carcinoma in situ). The increased use of prophylactic mastectomy over time was found to be more pronounced among women with breast cancer compared with those without. Women who underwent prophylactic mastectomies were more likely to be younger and white and to have private insurance compared with women who underwent therapeutic mastectomies and compared with all women with breast cancer. The International Classification of Diseases, Ninth Edition, Clinical Modification diagnostic code for prophylactic mastectomy introduced in 1995 was found to have low sensitivity for identifying prophylactic mastectomies in coded discharge data.

Conclusions: The results of the current analysis demonstrate that, although the discharge data alone are inadequate for surveillance purposes, combining these data with the cancer registry data allowed for the detailed examination of the prevalence of prophylactic mastectomies. Mastectomy among high-risk women for cancer prevention appears to be relatively uncommon, but the use of contralateral mastectomy in women with breast cancer is increasing.