A comparison of timely completion of hypofractionated and traditional adjuvant radiation therapy in early-stage breast cancer: Evidence of impact on reducing racial and socioeconomic disparities.

ABSTRACT

BACKGROUND: Timely completion of adjuvant radiation after breast conservation therapy is associated with decreased mortality and increased disease-free survival. Few data exist comparing timely completion between hypofractionated radiation and traditional radiation at a national level or across racial and socioeconomic cohorts. METHODS: A retrospective review of the National Cancer Database (2012-2016) on patients undergoing breast conservation therapy for early-stage breast cancer, specifically T1 or T2, N0, M0 patients, was performed. Multivariable logistic regression models were used to compare timely completion of hypofractionated radiation (within 5 weeks of initiation) and traditional radiation (within 7 weeks) across patient, tumor, and facility characteristics. RESULTS: In total, 210,816 patients met criteria, with 59.4% receiving traditional radiation (n = 125,140) and 40.6% receiving hypofractionated radiation (n = 85,676). Overall, 82.8% of patients achieved timely completion of radiation. Among hypofractionated radiation patients, 94.5% of patients achieved timely completion, whereas only 74.8% of traditional radiation patients achieved timely completion (P < .0001). Regarding race/ethnicity, all groups benefited substantially in timely completion of hypofractionated radiation over traditional radiation. However, both treatment cohorts demonstrated that Black (odds ratio (hypofractionated radiation) = 0.842, odds ratio (traditional radiation) = 0.821) and Hispanic (odds ratio (hypofractionated radiation) = 0.917, odds ratio (traditional radiation) = 0.907) patients had lower odds of timely completion compared to White patients (P < .0001). Lower high school graduation rate, median income for patients' ZIP code, and Medicaid were also associated with lower odds of timely completion for both hypofractionated radiation and traditional radiation (both P < .0001). CONCLUSION: Timely completion of radiation therapy in breast conservation therapy is greater for patients receiving hypofractionated radiation than traditional radiation across racial and socioeconomic cohorts. Disparities in timely completion were substantially reduced with hypofractionated radiation utilization. However, there are treatment disparities across racial and socioeconomic cohorts that persist in both treatment groups.