Studies have shown a decrease in bilateral mastectomy (BM) rates over the past five to ten years, but it is not clear if these decreases are the same across different patient races.

Using the National Cancer Database (NCDB) we examined BM rates for patients with AJCC Stage 0-II unilateral breast cancer from 2004 to 2020 for White versus nonwhite races (Blacks, Hispanics, and Asians). Multivariable logistic regression was used to identify patient and facility factors associated with BM by patient race from 2004 to 2006 and 2018–2020.

Of 1,187,864 patients, 791,594 (66.6%) had breast conserving surgery (BCS), 258,588 (21.8%) had unilateral mastectomy (UM) and 137,682 (11.6%) had BM. Our patient population was 927,530 (78.1%) White patients, 124,636 (10.5%) Black patients, 68,048 (5.7%) Hispanic patients, and 48,341 (4.1%) Asian patients. The BM rate steadily increased from 5.6% to 15.6% from 2004 to 2013, at which point the BM rate decreased to 11.3% in 2020. The decrease in BM was seen across all races, and in 2020, 6,487 (11.7%) Whites underwent BM compared to 506 (10.7%) Hispanics, 331 (9.2%) Asians, and 723 (9.1%) Blacks.

Race was a significant independent factor for BM in 2004–2006 and 2018–2020 but all races were more likely to undergo BM in 2004 compared to 2020 after adjusting for patient and facility factors. Compared to Whites, the odds of undergoing BM were OR 0.41 (0.37–0.45) in 2004 compared to OR 0.66 (0.63–0.69) in 2020 for Blacks, OR 0.44 (0.38–0.52) and OR 0.61 (0.57–0.65) for Asians and OR 0.59 (0.52–0.66) and OR 0.71 (0.67–0.75) for Hispanics, respectively.

BM rates for all races have declined since 2013, and differences in rates of BM amongst races have narrowed.