Racial disparity in dose intensity of early-stage breast cancer chemotherapy

6556 Background: There are persistent, entrenched racial disparities noted in breast cancer outcomes. A basis for these disparities can be racial inequality for stage matched Black vs. White women in receiving early-stage breast cancer (ESBC) chemotherapy dose intensity of, at minimum, 85% or more of chemotherapy (historic gold standard) within prescribed timeframe. Our study measured dose reductions, early terminations, and overall dose intensity of ESBC chemotherapy in urban breast cancer centers and compared by race. Methods: Using a longitudinal, comparative descriptive design, treatment characteristics were measured in women receiving ESBC cancer chemotherapy in seven cancer centers in Western PA and Eastern Ohio. Dosing scheduled was calculated per patient chemotherapy prescription. Actual dose was measured as percentage of chemotherapy received / prescribed in “prescribed time,” meaning exact, ideal time to complete chemotherapy calculated from dose initiated without delay, dose reduction or early stoppage. The second measurement, “in any time,” measured chemotherapy completed over any course of time, incorporating delays and reductions. Results were dichotomized according to 85% of prescribed dose for both outcomes and compared by patient self-reported race (Black or White). Results: This study was conducted from August 2017 through June 2022. N=260 patients, race self-reported as 100 Black (38.5%) and 160 White (61.5%). Overall, n=36 (13.8%) had early termination of therapy. Early termination was more common for Black patients, 21%, vs 10% for White patients (p=.04). N=100 (38.3%) of all patients had some dose reduction, racially divided by 46.4% of Black patients vs. 34.3% of White patients, NS. By projected endpoint, Black patients received 77% (SD 24.1) of prescribed chemotherapy; White patients 86.7% (SD 16.6), p=.001. By “in any time” endpoint, Black patients received 86.5%, (SD 22.8) of prescribed therapy, White patients received 93.5% (SD 13.2), p=.002. By “in any time” measurement, 15% of White patients and 25% of Black patients did not receive the gold standard of 85% of prescribed chemotherapy. N= 7 of delays or terminations were due to disease progression, or poor response, and rarely, (n=4) to patient nonadherence. Largely, delays and early cessation were due to chemotherapy toxicity. Conclusions: Racial disparities in dose intensity and alterations of prescribed ESBC chemotherapy must be eliminated. Further examining the racial differences around dose delays and early chemotherapy termination, including racial barriers to patient- clinician communication around chemotherapy related toxicity, is essential to ensure equitable ESBC care and outcomes.