Time to initiation of neo-adjuvant chemotherapy for breast cancer treatment does not influence patient survival: A study of US breast cancer patients.

Delays in the initiation of adjuvant chemotherapy or radiation therapy are associated with worse outcomes in patients undergoing treatment for breast cancer. However, the impact of the time to initiation of neo-adjuvant chemotherapy (NAC) on patient outcomes has not previously been studied. The purpose of this study was to determine whether delays in NAC initiation impact patient survival. The National Cancer Database was queried for women ≥ 18 years old who underwent NAC within 6 months of being diagnosed with stage I-III invasive breast cancer in 2010-2011. ER+ or PR+, Her2- cancers were excluded from analysis. Multivariable Cox proportional hazard modeling was used to evaluate the relationship between time to NAC, sociodemographic, diagnosis, and treatment factors with patient survival. The median age of the 12 806 women included in this study was 52 (range 21-90) with 62% presenting with cT2 disease and 62% with nodal involvement. Half of the women (50%) had triple negative, 30% ER/PR+Her2+ and 20% ER-PR-Her2+ cancers. The median time to starting NAC was 4 weeks (range 0-26) for all subtypes. Time to NAC initiation was not associated with a difference in survival for triple negative or Her2+ cancers. Delays from diagnosis to starting NAC are not associated with worse survival for patients with Her2+ or triple negative breast cancer. This study demonstrates that the majority of women in the modern era start NAC in a timely fashion and delays in starting NAC within 6 months of diagnosis do not impact long-term patient outcomes.