Trends and disparities in the utilization of hypofractionated neoadjuvant radiation therapy for rectal cancer in the United States.

BACKGROUND: Neoadjuvant conventionally fractionated radiotherapy (CFRT) versus hypofractionated radiotherapy (HFRT) for rectal cancer (RC) is among the most controversial and debatable areas of radiotherapeutic management. This is the only known study evaluating the utilization of neoadjuvant HFRT for RC in the United States, and focuses on trends and health disparities.
METHODS: The National Cancer Data Base was queried [2004-2015] for newly-diagnosed cT3-T4 Nany or cTany N1-2 M0 rectal adenocarcinoma undergoing neoadjuvant RT, with or without chemotherapy, followed by resection. Following analysis based on temporal trends, multivariate logistic regression determined factors associated with receipt of HFRT.
RESULTS: Altogether, 29,994 patients met study criteria: 29,724 (99%) were treated with CFRT, and 270 (1%) with HFRT. Temporally, utilization of HFRT rose significantly, from 0.2% in 2004 to 2.0% in 2015, with the steepest slope at most recent time periods. HFRT was more likely administered to older patients, those with more comorbidities, and node-positive disease (P<0.05 for all). There were racial differences, as African-Americans were independently less likely to receive HFRT (P=0.043). The two strongest predictors of HFRT administration (by odds ratio) were time period and therapy at academic centers (P<0.05 for all).
CONCLUSIONS: Although HFRT is underutilized in the US, its use is rising and has increased nearly tenfold over the last decade. Disparities in HFRT delivery are emphasized, especially concerning disease-/patient-specific factors, socioeconomic status, and race. These data may serve as a benchmark for future investigation as well as for health disparities in the radiotherapeutic treatment of RC.