Contralateral Prophylactic Mastectomy Associated with Survival in Select Group of Breast Cancer

Contralateral Prophylactic Mastectomy Associated with Survival in Select Group of Breast Cancer Patients

Contralateral prophylactic mastectomy (CPM), a preventive procedure to remove the unaffected breast in patients with disease in one breast, may only offer a survival benefit to breast cancer patients age 50 and younger, who have early-stage disease and are estrogen receptor (ER) negative, according to researchers at The University of Texas M. D. Anderson Cancer Center.

Published online today in the Journal of the National Cancer Institute, it's the first population-based study to find an association between the procedure and survival in any group of breast cancer patients. The findings should offer evidence to both the women making this often agonizing decision and the physicians responsible for their care.

According to Isabelle Bedrosian, M.D., assistant professor in M. D. Anderson's Department of Surgical Oncology, a growing number of breast cancer patients are opting for the procedure; recent statistics have shown that the rate of CPM in women with stage I-III breast cancer increased by 150 percent from 1998 to 2003 in the United States.

"In our clinic, we've seen a dramatic increase in the number of women requesting CPM, and across the breast cancer community, studies have shown that the utilization of the procedure is skyrocketing," said Bedrosian, the study's co-corresponding author. "Until now, we've counseled these patients on a very important, personal decision in a vacuum. With our study, our goal was to understand the implications of the surgery and who may benefit."

For the retrospective, population-based study, the researchers used the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) registry, the premier population-based cancer registry now representing 26 percent of the country's population, to identify 107,106 breast cancer patients who underwent a mastectomy for treatment, as well as a subset of 8,902 women who had CPM. All of the women were treated for stages I - III breast cancer between 1998 and 2003. Patients were stratified for ER status, stage of disease and age. Breast cancer-specific survival served as the study's primary endpoint.

Rigorous analysis was paramount in the design of the study, said George J. Chang, M.D., assistant professor in M. D. Anderson's Department of Surgical Oncology.

"It was important to take a critical eye and look at all the different ways the data could be misinterpreted to ensure that biases were not impacting our findings," said Chang, the study's co-corresponding author. "Using multi-variable analysis as well as risk stratification, we did our analysis in many different ways - through SEER, comparing the survival of these patients to that of the general population, as well as examining non-cancer related versus cancer-specific survival. All alternative analyses resulted in the same conclusion; we found one group for whom this surgery offers a true survival benefit."