Race/Ethnicity May Influence Local Recurrence in DCIS, Adjuvant Treatment

Among women with ductal carcinoma in situ (DCIS) treated between 1978 and 2016 at Memorial Sloan Kettering Cancer Center (MSK) in New York City, Black women had a significantly higher rate of 10-year local recurrence (LR) following breast-conserving surgery (BCS) overall and after receiving radiotherapy (RT) compared with Asian, Hispanic, and White women, according to a spotlight presentation on day 1 of the San Antonio Breast Cancer Symposium.

“Differences in outcomes of patients with DCIS by ethnicity and race have not been well studied,” presenting author Natalia Polidorio, MD, PhD, a clinical research fellow in MSK’s Department of Surgery said. “We aimed to compare LR rates in women with DCIS treated with BCS across racial and ethnic groups."

Black patient with doctor | Image Credit: Seventyfour - stock.adobe.com

Of the 4207 cases included in this retrospective analysis, 9% were Black women vs 80% White women, 6% Asian women, and 5% Hispanic Women. Their median (IQR) age was 57 (49-67) years, the median follow-up was 8.8 years, 56% received RT, and 26% received endocrine therapy. There were 602 LR events, 52% of which were DCIS and 47% invasive disease. The 10-year LR rate was 15%, or 11% among those who received RT vs 20% (P < .001) among those who did not receive RT.

The Black women were older (P < .001), had more clinical presentation (P = .006), and together with Hispanic women were more likely to require 3 or more excisions (P = .006). They also accounted for the highest cumulative incidence of LR, at 25%, compared with 15% of Hispanic, 14% of White, and 11% of Asian women. Even when accounting for receipt (P = .04) or not (P = .3) of RT, respectively, Black women still had the highest rates of LR (31% and 21%) vs Hispanic (25% and 9%), White (19% and 11%), and Asian (13% and 9%) women.

Even after multivariate analysis, using White women as a reference, Black women with DCIS had a 48% higher risk of LR after BCS (HR, 1.48, 95% CI, 1.12-1.96; P = .01) vs a 7% higher risk among Hispanic women (HR, 1.07; 95% CI, 0.73-1.58) and a 29% reduced risk among Asian women (HR, 0.71; 95% CI, 0.47-1.07).

Breaking these data down, most (78%) of the Black women in this analysis were aged 50 to 79 years vs 61% of Asian, 65% of Hispanic, and 70% of White women. Fifteen percent had clinical presentation vs 13% of Asian, 11% of Hispanic, and 9.7% of White women. Eighteen percent had margins of less than 2 mm vs 14% of Asian, 12% of Hispanic, and 16% of White women, and 82% had margins of 2 mm or more vs 86%, 88%, and 84%, respectively. Further, they had the lowest rate of radiological presentation, at 85% vs 87%, 89%, and 89.3%.

Univariate analysis, too, showed a higher overall risk of LR among Black women (HR, 1.43; 95% CI, 1.09-1.87; P = .04) compared with Hispanic (HR, 1.08; 95% CI, 0.74-1.57) and Asian women (HR, 0.77; 95% CI, 0.52-1.14). Factors in this analysis associated with a lower risk of LR were younger (50 -79 years) vs older (80 years and older) age (0.71; 95% CI, 0.60-0.85; P < .001), having a year of diagnosis of 1999 or later (HR, 0.77, 95% CI, 0.65-0.92; P = .005), having low-/intermediate-grade disease (HR, 0.92; 95% CI, 0.77-1.09; P = .3), having margins of 2 mm or more (HR, 0.65; 95% CI, 0.53-0.80; P < .001), receiving endocrine therapy (0.46; 95% CI, 0.37-0.58; P < .001), and receipt of RT (HR, 059; 95% CI, 0.50-0.69; P < .001).

The higher risk of LR among Black women with DCIS following BCS was also seen despite the following:

• The same amount of Black vs White women (20%) had been living with their diagnosis since 1998 or earlier
• For low-/intermediate-grade disease, Black women had equivalent rates vs White women (both 66%); only Hispanic women had a lower rate (65%)
• For high-grade disease, Black women had rates equivalent to White women (both 34%) and lower rates vs Hispanic women (35%); only Asian women had a lower rate (29%)
• More Black women (35%) had received endocrine therapy vs Asian (27%), Hispanic (26%), and White women (26%)
• Black women had the second highest rate of RT (59%) vs Hispanic women (63%), which was also equivalent to Asian women (59%) and higher than White women (55%)

No associations were seen with family history, grade, necrosis, or number of excisions.

The conclusions from this research are that despite adjusting for known clinicopathologic and treatment risk factors, Black women with DCIS still had a significantly higher rate of LR even after BCS. Because of this, the authors recommended when making decisions regarding adjuvant therapy, clinicians need to consider these differences.

Reference

Polidorio N, Jones VM, Sevilimedu V, et al. Impact of race and ethnicity on recurrence risk in patients with ductal carcinoma in situ treated with breast-conserving surgery. Poster presented at: San Antonio Breast Cancer Symposium; December 5-9, 2023; San Antonio, TX. Poster: PS01-07.