Trends in use of contralateral prophylactic mastectomy by racial/ethnic group and ER/PR status among patients with breast cancer: A SEER population-based study

Background: While differences in CPM use between White and Black patients are well known, it is not clear whether CPM use differs by estrogen/progesterone receptor (ER/PR) status of tumors and whether racial/ethnic differences in the use are affected by ER/PR status, which varies between racial groups. The purpose of this study was to investigate whether CPM usage differs by racial/ethnic group and ER/PR status among patients in the Surveillance, Epidemiology, and End Results (SEER) data. Methods: The study subjects were women with histologically confirmed unilateral breast cancer who underwent breast surgery between 1998 and 2011. Age-adjusted CPM use as a proportion of all surgically treated patients or all patients who had mastectomy was analyzed by racial/ethnic group, tumor behavior, and ER/PR status. Temporal trends in age-adjusted CPM use were presented by ER/PR status and racial/ethnic group. Results: The analyses stratified by ER/PR status showed significant racial/ethnic differences in age-adjusted CPM use with non-Hispanic White and non-Hispanic Asian/Pacific Islander (API) patients having the most and least CPM use. Age-adjusted CPM use was significantly higher for ER+/PR+ tumors than ER-/PR- ones for each race/ethnicity group among patients with mastectomy. However, among patients with any breast surgeries, the only difference was a higher proportion of CPM use for ER-/PR- tumors (8.6%) than ER+/PR+ tumors (8.0%) in non-Hispanic Whites. CPM use has increased over time in all racial/ethnic groups despite ER/PR status. Conclusion: CPM usage was lower not only in non-Hispanic Blacks, but also in non-Hispanic API and Hispanic patients compared to non-Hispanic White patients. CPM usage tended to be higher for ER+/PR+ tumors, but the results varied when different denominators (all mastectomies vs. all breast surgeries) were used.