Short-course versus long-course neoadjuvant chemoradiotherapy in patients with rectal cancer: preliminary results of a randomized controlled trial

Colorectal cancer is becoming an increasing concern in the middle-aged population of Iran. This study aimed to compare the preliminary results of short-course and long-course neoadjuvant chemoradiotherapy treatment for rectal cancer patients.Patients in group I received three-dimensional conformational radiotherapy with a dose of 25 Gy/5 fractions in 1 week plus concurrent XELOX regimen (capecitabine 625 mg/m2 from day 1-5 twice daily and oxaliplatin 50 mg/m2 on day 1 once daily). Patients in group II received a total dose of 50-50.4 Gy/25-28 fractions for 5 to 5.5 weeks plus capecitabine 825 mg/m2 twice daily. Both groups underwent delayed surgery at least 8 weeks after radiotherapy completion. The pathological response was assessed with tumor regression grade.In this preliminary report on complications and pathological response, 66 patients were randomized into study groups. Mean duration of radiotherapy in the two groups was 5 ± 1 days (range, 5 to 8 days) and 38 ± 6 days (range, 30 to 58 days). The median follow-up was 18 months. Pathological complete response was achieved in 32.3% and 23.1% of patients in the short-course and long-course groups, respectively (p = 0.558). Overall, acute grade 3 or higher treatment-related toxicities occurred in 24.2% and 22.2% of patients in group I and II, respectively (p = 0.551). No acute grade 4 or 5 adverse events were observed in either group. Within one month of surgery, no significant difference was seen regarding grade ≥3 postoperative complications (p = 0.333).For patients with rectal cancer located 5 cm above the anal verge, short-course radiotherapy with concurrent and consolidation chemotherapy and delayed surgery is not different in terms of acute toxicity, postoperative morbidity, complete resection, and pathological response compared to long-course chemoradiotherapy.