Hospital variance in neoadjuvant rectal cancer treatment and the influence of a national guideline update: Results of a nationwide population-based study

INTRODUCTION: The aim of this study was to examine the hospital variation in neoadjuvant treatment of rectal cancer according to the different risk groups (low-, intermediate- and high-risk) and evaluate the influence on survival. MATERIALS AND METHODS: Patients with non-metastasized rectal cancer diagnosed between 2009 and 2016 were selected from the Netherlands Cancer Registry. The observed and case-mix adjusted distribution of the different neoadjuvant treatment schemes (none, radiotherapy (RT), chemoradiotherapy (CRT)) by hospital of diagnosis were generated for each risk group in the cohorts before and after the national guideline update of 2014. RESULTS: A total of 25,306 patients were included and after case-mix adjustment, hospital of diagnosis was found to have a significant impact on neoadjuvant treatment administration in each of the three risk groups (p < 0.001). Overall survival was however not influenced, except for the high-risk group where hospitals with highest rates of CRT were associated with a better 5-years overall survival (HR 0.79; p = 0.03). After guideline revision, the rate of patients in the low-risk group who did not undergo RT increased from a median of 30.8% to 90.5% (p < 0.001). CONCLUSION: Although a significant change in treatment was observed after revision of the national guidelines, a wide range of hospital variation still exists in administered neoadjuvant treatment in rectal cancer patients. High-risk rectal cancer patients had a better survival when treated in hospitals with the highest rates of CRT provided. In order to minimize treatment differences, further research into the causes of this variation and implementation of regionalized MDTs may be warranted