Neoadjuvant chemotherapy with XELOX regimen for locally advanced operable colon cancer patients: a prospective phase II trial (NCT02415829).

e15047 Background: Several studies showed that the neoadjuvant chemotherapy (NAT) is an effective treatment of solid tumor malignancies. This study was a prospective, single-arm phase II trial to assess the efficacy and safety of XELOX regimen as neoadjuvant chemotherapy for locally advanced colon cancer patients. Methods: Patients with CT-defined T4 or lymph node-positive colon cancer were enrolled. After radiological staging, patients were treated with 3 cycles of neoadjuvant chemotherapy consisting of oxaliplatin, 130 mg/m² on day 1, with capecitabine, 1000 mg/m² twice daily for 14 days every 3 weeks (the XELOX regimen), followed by tumor resection, and then with another 5 cycles of adjuvant chemotherapy with the XELOX regimen. Radiological response was evaluated after 2 cycles of neoadjuvant chemotherapy. The pathological tumor response in the primary tumor was evaluated according to tumor regression grade (TRG) score. The primary endpoints were tumor response rate. This trial is registered with ClinicalTrials.gov, number NCT02415829. Results: 46 patients were enrolled and received treatment. 5 patients were only received 1 cycle of NAC and excluded. 41 patients received at least 2 cycles of neoadjuvant chemotherapy and R0 resection. The total clinical response rate was 70.7% (29/41) including a complete response and partial response rate of 2.4% (1/41) and 68.3% (28/41), respectively. Stable disease was observed in 29.3% (12/41) of patients and no progressive disease in all patients. The total pathological response rate was based on TRG score. pCR(TRG0) , major regression(TRG1) and at least moderate regression(TRG2) were achieved in 1 (2.4%), 2 (4.9%), and 25 patients (61.0%), respectively. Grade 3/4 treatment toxicities were hematological toxicities and developed in 4 patients. Emergency operation conditions were observed in 3 patients with perforation or obstruction. Operation complications rate was 4.2% (1/46) with wound infection and mortality rate was 0. Conclusions: The results suggest that neoadjuvant chemotherapy with XELOX is an effective, feasible and safe treatment for patients with locally advanced colon cancer. Clinical trial information: 02415829.