Neoadjuvant Chemotherapy in Patients With Intermediate Risk Upper and Mid Rectal Cancer

The purpose of this study is to determine whether 4 cycles of neoadjuvant CapOx chemotherapy is more effective than the upfront surgery in patients with intermediate risk CRM"-" mid and upper rectal cancer.

This trial aims to investigate the efficacy of neoadjuvant chemotherapy compared to upfront surgery in intermediate risk rectal cancer patients. This is a prospective multicenter open-label randomized phase III clinical trial. Patients will be randomized using an online randomization system to receive either 4 cycles of neoadjuvant CapOx (oxaliplatin 130 mg/m2 iv day 1, capecitabine 2000 mg/m2 per os bid days 1-14) chemotherapy and surgery or surgery alone. A stratification will be performed based on N stage, tumor location in the middle or upper rectum and clinical center. Patients with cT3-4aN1-2M0, T4aN0M0 cancer in the upper rectum and сТ2-Т3bN1M0 (based on preoperative MRI) cancer in the middle rectum are included. All patients are potential candidates for adjuvant chemotherapy, according to preoperative staging. Chemoradiotherapy (50 Gy with concomitant capecitabine 825 mg/m2 per os bid on radiation days) will be performed for patients with tumor progression after neoadjuvant chemotherapy. The decision to proceed with adjuvant chemotherapy postoperatively will be based on pTNM stage in both treatment arms, according to actual treatment guidelines. The target accrual is 280 patients in each treatment arm (including 10% potential data loss) based on potential benefit of 10% 3-yr disease-free survival (75% vs 85%), α=0,05, power 80% in the experimental arm. An interim analysis is planned after 50% of the patients will reach a 3-year followup. Pelvic Magnetic Resonance Imaging (MRI) is performed in all patients for staging before and after neoadjuvant chemotherapy and before surgery. Pelvic MRI isbject to central review. Conduction of this study and data collection are controlled by a local institutional board.