Impact of delays in neoadjuvant chemotherapy initiation on pathologic complete response among patients with HER2-positive or triple negative breast cancer.

• DOI: 10.1200/op.2024.20.10_suppl.102
• Publication Date: 2024-09-30T13:33:33Z
• Authors: Margaux Wooster; David DeStephano; Melissa P. Beauch...; Shikun Wang; Chin Hur; Jason Dennis Wright; Dawn L. Hershman; Melissa Kate Acco...
• Keywords: Complete response; Triple-negative breast cancer; Triple negative

102 Background: Pathologic complete response (pCR) is used as a surrogate endpoint for overall survival (OS) in high-risk early-stage breast cancer (BC). pCR rates vary according to BC molecular subtype and have the highest association with OS triple negative (TNBC) HER2-positive (HER2+) BC. In these subgroups, neoadjuvant chemotherapy (NACT) often standard of care. We evaluated delays NACT initiation (NACTI) pCR. Methods: conducted retrospective cohort study using National Cancer Database. Eligibility included age ≥18 years, diagnosis cT2+ or lymph node positive HER2+ TNBC between 1/1/2010 – 12/31/2020, who were treated within 180 days diagnosis. Time (TTC) was recorded days. Patients categorized by receptor status. AJCC 7 th 8 edition T N staging define (pT0 pTis pN0 pN0I-). Delay defined TTC > 60 Multivariable logistic regression, adjusted demographic, socioeconomic tumor characteristics, calculate odds associated delays. A sensitivity analysis defining delay >30 >90 also conducted. Results: identified 105,352 eligible patients, 73% White, 19% Black, 3% Asian, 4% Other/Unknown. Median at 52 years (range 18-90), median 32 0-180). There 56,868 patients 48,484 TNBC; 9% delayed each group. Among all 39.1% achieved pCR: 35.0% compared 39.5% without delay. 30% 25% 31% (p < 0.0001 all). multivariable analysis, disease (OR 0.85, 95%CI 0.79-0.92) 0.80, 0.73-0.87) less likely achieve if 30 lower likelihood achieving 90 (Table). Conclusions: Delays NACTI >60 among an independent predictor not Given known factors treatment, interventions aimed reducing may reduce disparities outcomes. Future studies identify causes downstream impact are needed ultimately develop that mitigate effects TNBC, where OS. Association experience regression* n(complete case) = 77,690. Subgroup >30-day NACTIOR (95% CI) >60-day >90-day HER2+n =41,672 0.91 (0.87-0.95) 0.85 (0.79-0.92) 0.93 (0.80-1.07) TNBCn 36,018 0.87 (0.83-0.92) 0.80 (0.73-0.87) 0.78 (0.65-0.92) *Adjusted characteristics.