Complete Neoadjuvant Treatment for Rectal Cancer: The Brown University Oncology Group CONTRE Study

Following preoperative chemoradiation and surgery, many patients with stage II to III rectal cancer are unable to tolerate full-dose adjuvant chemotherapy. BrUOG R-224 was designed to assess the impact of COmplete Neoadjuvant Treatment for REctal cancer (CONTRE), primary chemotherapy followed by chemoradiation and surgery, on treatment delivery, toxicities, and pathologic response at surgery.

Patients with clinical stage II to III (T3 to T4 and/or N1 to N2) rectal cancer received 8 cycles of modified FOLFOX6 followed by capecitabine 825 mg/m bid concurrent with 50.4 Gy intensity-modulated radiation therapy. Surgery was performed 6 to 10 weeks after chemoradiation.

Thirty-nine patients were enrolled between August 2010 and June 2013. Median age was 61 years (30 to 79 y); 7 patients (18%) were clinical stage II and 32 (82%) stage III. Thirty-six patients (92%) received all 8 cycles of mFOLFOX6, of whom 35 completed subsequent chemoradiation; thus 89% of patients received CONTRE as planned. No unexpected toxicities were reported. All patients had resolution of bleeding and improvement of obstructive symptoms, with no complications requiring surgical intervention. Pathologic complete response (ypT0N0) was demonstrated in 13 patients (33%; 95% CI, 18.24%-47.76%).

CONTRE seems to be a well-tolerated alternative to the current standard treatment sequence. Evaluating its impact on long-term outcomes would require a large randomized trial, but using pathologic response as an endpoint, it could serve as a platform for assessing the addition of novel agents to preoperative treatment in stage II to III rectal cancer.