NCI's Cancer Research Network Studies Prophylactic Mastectomy
The NCI-supported Cancer Research Network (CRN), consisting of a dozen managed care organizations, is leveraging multidisciplinary teams of scientists to evaluate effective community interventions. A good example of CRN's collaborative approach is the "Program Testing Early Cancer Treatment and Screening" (PROTECTS) project, which recently produced two studies showing the preventive value of mastectomy in women at risk for breast cancer. (See related CRN study.)
One of the studies, published online March 28 in the Journal of Clinical Oncology, analyzed the effectiveness of contralateral prophylactic mastectomy (CPM), in which women with breast cancer in one breast also have their healthy breast removed.
Dr. Lisa J. Herrinton, research scientist at Kaiser Permanente Northern California, and her colleagues devised a study that used data drawn from six of the participating health plans. The researchers examined automated health care data for 56,400 women diagnosed with breast cancer between 1979 and 1999. They identified 1,072 patients who had CPM and found that the procedure cut the risk of breast cancer occurring in the healthy breast by 97 percent. The risk of death from breast cancer was also 43 percent lower compared with a group of women with breast cancer who did not have CPM.
In an accompanying editorial, Dr. Kathy J. Helzlsouer, of the Johns Hopkins University School of Public Health, points out that there is an "overall low risk of second primary tumors" in women with unilateral breast cancer. The 43 percent reduction in risk of death among CPM patients translated into an 8 percent mortality rate during the average 5 years of follow-up for those who had CPM, compared with 12 percent mortality among patients who did not have the procedure.
The second study, published in the March 14 Archives of Internal Medicine, examined the usefulness of prophylactic mastectomy in women who did not have breast cancer but were at elevated risk for it, based on family history, atypical hyperplasia, or one or more unusual but benign biopsies. Dr. Ann M. Geiger of Kaiser Permanente Southern California and her colleagues used automated health care data to conduct a case-cohort study of 666,800 women with those risk factors.
Among that group, 276 had undergone bilateral prophylactic mastectomy (BPM) - removal of both healthy breasts. Less than 1 percent of those women subsequently developed breast cancer, compared with 4 percent of the at-risk women who did not have the BPM procedure.
"Weighing the risks and benefits of options to reduce second breast cancer in women with a personal history of breast cancer requires the quantification of harms as well as benefits," Dr. Helzlsouer concludes. "The next step is quantifying the harms, both physical and psychological, so women can weigh all of their options and make informed choices."
For more information on the CRN, visit http://crn.cancer.gov/.