Population-level utilisation of neoadjuvant radiotherapy for the treatment of rectal cancer

International clinical guidelines recommend long- or short-course neoadjuvant radiotherapy for locally advanced rectal cancer. This study aims to examine variation in the use of neoadjuvant radiotherapy for rectal cancer and identify patient and hospital factors that underpin this variation.

We conducted a retrospective, consecutive cohort study using statewide hospitalisation and radiotherapy data from New South Wales, Australia, 2013-2018. Included participants had a primary rectal adenocarcinoma and underwent surgical resection. Factors associated with the use or not of any neoadjuvant radiotherapy, and short versus long-course were explored using multilevel logistic regression models.

Of the 2912 people included in the study, 43% received neoadjuvant radiotherapy. There was significant variation in the use of neoadjuvant radiotherapy depending on geographic location. Abdominoperineal excision (odds ratio [OR] = 1.87, 95% confidence interval [CI] = 1.53-2.28) and having surgery in a public hospital (OR = 2.34, 95% CI = 1.92-2.87) were both predictors of use. Among those receiving neoadjuvant radiotherapy, 17% received short-course therapy, with short-course declining over the study period.

The use of neoadjuvant radiotherapy for rectal cancer is highly variable, with differences only partially explained by assessable patient-or hospital-level factors. Understanding neoadjuvant radiotherapy utilisation patterns may assist in identifying barriers and opportunities to improve adherence to clinical guidelines.