Background: A 2004 German study found preoperative chemoradiotherapy followed by postoperative chemotherapy provided increased local control and reduced toxicity over postoperative chemoradiotherapy in stage II/III rectal cancer, though a statistically significant advantage in overall survival was not observed. We examined similar survival differences and the utilization of appropriate therapy on a larger scale.
Methods: This study retrospectively examined patients diagnosed with stage II/III rectal cancer from 2006 to 2011 using a participant user file from the National Cancer Database, a data registry jointly sponsored by the American College of Surgeons and the American Cancer Society capturing approximately 70% of newly diagnosed cancer cases nationwide. Overall survival differences between treatment modalities were assessed using life tables and pairwise comparisons, and changes in the utilization of these treatments were examined.
Results: Of 40,546 patients diagnosed with stage II/III rectal cancer, 27,014 (66.6%) received therapy consisting of surgery, chemotherapy, and radiation. Those administered preoperative chemoradiotherapy followed by postoperative chemotherapy had the highest 5-year survival rate (stage II 81.4%, stage III 71.2%), but the difference was not significant against postoperative chemoradiotherapy in stage III disease (69.9%) after the Bonferroni correction was applied. Five-year survival was higher in postoperative (stage II 76.0%, stage III 69.9%) than that in preoperative (stage II 72.5%, stage III: 65.8%) chemoradiotherapy in both stages. Preoperative chemoradiotherapy remains the most commonly administered (60.6% in stage II and 46.0% in stage III), but preoperative chemoradio-therapy followed by postoperative chemotherapy has been steadily rising (2006: 12.2% in stage II, 16.5% in stage III vs 2011: 22.8% in stage II, 28.0% in stage III).
Conclusions: A survival benefit of preoperative chemoradiotherapy followed by postoperative chemotherapy in stage II disease was observed, along with a nonsignificant advantage in stage III disease. The utilization of preoperative chemoradiotherapy followed by postoperative chemotherapy increased, but preoperative chemoradiotherapy remained most prevalent despite its lesser overall survival. Cox regression will be performed prior to the AVAHO annual meeting to evaluate the impact of other characteristics such as age, insurance, income, and comorbidities on survival.
