Benefit of adjuvant chemotherapy in lymph node-negative, T1b and T1c triple-negative breast cancer.

INTRODUCTION: Current guidelines recommendations regarding chemotherapy in small (T1b and T1c), node-negative triple-negative breast cancer (TNBC) differ due to lack of high-quality data. Our study aimed to assess the benefit of adjuvant chemotherapy in patients with T1bN0M0 and T1cN0M0 TNBC. METHODS: We obtained data from the Surveillance, Epidemiology, and End Results database for patients with node-negative, T1b/T1c TNBC diagnosed between 2010 and 2020. Logistic regresion models assessed variables associated with chemotherapy administration. We evaluated the effect of chemotherapy on overall survival (OS) and breast cancer specific survival (BCSS) with Kaplan-Meier methods and Cox proportional hazards methods. RESULTS: We included 11,510 patients: 3,388 with T1b and 8,122 with T1c TNBC. During a median follow-up of 66 months, 305 patients with T1b and 995 with T1c died. After adjusting for clinicopathological, demographic and treatment factors, adjuvant chemotherapy improved OS in T1b TNBC (HR, 0.52; 95% CI, 0.41-0.68 p < 0.001) but did not improve BCSS (HR, 0.70; 95% CI, 0.45-1.07; p = 0.10); the association between chemotherapy and BCSS was not statistically significant in any subgroup. In T1c TNBC, adjuvant chemotherapy improved OS (HR, 0.54; 95% CI, 0.47-0.62; p < 0.001) and BCSS (HR, 0.79; 95% CI, 0.63-0.99; p = 0.043); the benefit of chemotherapy in OS varied by age (Pinteraction=0.024); moreover, the benefit in BCSS was similar in all subgroups. CONCLUSIONS: Our study results support the use of adjuvant chemotherapy in patients with node-negative, T1c TNBC. Patients with node-negative, T1b TNBC had excellent long-term outcomes; furthermore, chemotherapy was not associated with improved BCSS in these patients.

Racial disparities in treatment and outcomes between non-Hispanic Black and non-Hispanic White women with nonmetastatic inflammatory breast cancer.

PURPOSE: The incidence rate of inflammatory breast cancer (IBC) is higher among non-Hispanic Black (NHB) than non-Hispanic White (NHW) women. We examined the differences in treatment and outcomes between NHB and NHW women with IBC, accounting for demographic, clinicopathological, and socioeconomic factors. METHODS: We collected data from the Surveillance, Epidemiology, and End Results database for NHB and NHW women with IBC diagnosed between 2010-2016. We analyzed the odds of receiving chemotherapy, radiation, and surgery between NHB and NHW women. We evaluated overall survival (OS) with Kaplan-Meier methods and Cox proportional hazards methods. Competing risk analysis was used to compare the risk of breast cancer death between NHB and NHW women. We also evaluated the magnitude of survival disparities within the strata of demographic, socioeconomic, and treatment factors. RESULTS: Among 1,652 NHW and 371 NHB women with IBC, the odds of receiving chemotherapy, surgery, and radiation were similar for NHB and NHW. After 39-month follow-up, the median OS was 40 and 81 months for NHB and NHW, respectively (p < 0.0001). The risk of breast cancer death was higher for NHB than NHW women (5-year risk of breast cancer death, 51% vs. 35%, p < 0.0001). CONCLUSION: After adjustment for demographic, clinicopathological, and socioeconomic factors; NHB women with IBC had similar odds of receiving surgery, chemotherapy, and radiation therapy, but were more likely to die of the disease compared to their NHW counterparts. Our findings suggest the presence of masked tumor biology, treatment, or socioeconomic factors associated with race that can lead to worse IBC outcomes.