Effectiveness of neoadjuvant concurrent chemoradiotherapy versus up-front proctectomy in clinical stage II–III rectal cancer: A population-based study

Aims: Neoadjuvant concurrent chemoradiotherapy (NCCRT) is currently the preferred treatment for rectal cancer of clinical stage II–III based on its efficacy in clinical trials. The population-based effectiveness of NCCRT is rarely reported on in the literature. The purpose of our study is to investigate the nationwide population-based effectiveness of NCCRT as compared with up-front proctectomy. Methods: In this retrospective cohort study, we identified the study population by linking datasets including the cancer registry, death registry and other related files in Taiwan. We identified all patients with rectal adenocarcinoma of American Joint Committee on Cancer clinical stage II or III who were diagnosed in 2007 or 2008 and received either NCCRT or up-front proctectomy. We included patients' age, gender, residence, socioeconomic status and clinical stage as covariables. We used overall survival as the measure of effectiveness. The Cox proportional-hazards regression model was used for statistical analyses. We further conducted sensitivity analyses, one in only those who received optimal postoperative chemotherapy and one in two subgroups matched for propensity score. Results: We included 1933 patients (NCCRT: 424; up-front proctectomy: 1509) in the study population. NCCRT was associated with improved survival as compared with up-front proctectomy (adjusted hazard ratio of death 0.656; 95% confidence interval 0.495–0.871). Our results were robust in the sensitivity analyses. Conclusion: We demonstrated that the use of neoadjuvant concurrent systemic therapy and radiotherapy is associated with better effectiveness in rectal adenocarcinoma of clinical stage II–III as compared with up-front proctectomy. Further studies are needed to elucidate the subgroups most likely to benefit and to clarify NCCRT's cost-effectiveness.