This study sought to determine whether additional radiotherapy is necessary in patients after optimal surgery for stage IIA rectal cancer and how the different covariates influence the efficacy of radiotherapy. The first primary rectal cancer was identified from the 1988-December 2013 Surveillance, Epidemiology and End Results database. We identified 13647 patients with IIA rectal cancer, in which 39.6% received neo-adjuvant radiotherapy and in another 14.96% patients the adjuvant radiotherapy were performed. Neo-adjuvant or adjuvant radiotherapy group had better survival with 10-Year cancer-specific survival estimates as 75.1% and 73.8% compared to 68.4% of no radiotherapy group (P < 0.01). Adjusted hazard ratio (HR) demonstrated neo-adjuvant and adjuvant radiotherapy (HR: 0.814 and 0.848) were all associated with significantly decreased risk for cancer death. However, radiotherapy did not seem to yield the same survival benefit in selected population. Adjusted stratified analysis demonstrated patients with increasing age, relative large tumor size, and more retrieved regional lymph nodes had no additional benefit for cancer specific survival based on radiation use. In conclusions, unselected patients with stage IIA rectal cancer receiving radiotherapy experienced better survival in comparison to patients without radiation. However, additional radiotherapy is not beneficial for all.
Keywords: outcomes; radiotherapy; rectal cancer; stage IIA.