Tumor response to neoadjuvant chemoradiation in rectal cancer: predictor for surgical morbidity?

Increasing the rate of pathological complete remissions after neoadjuvant chemoradiation of rectal cancer has become a strategy to further improve the long-term oncological outcome of patients. This report evaluates the influence of preoperative intensified radiochemotherapy on the rate and outcome of surgical complications.

Patients with primary rectal cancer at stages cT3/4cNx or N+ without metastasis were preoperatively treated either with capecitabine and irinotecan or with capecitabine, irinotecan and ceutximab with a concurrent radiation (50.4 Gy). Surgery was scheduled 4-7 weeks after completion of the chemoradiation. Perioperative complications were prospectively documented during the patient's hospital stay.

Fifty-nine patients (median age 60; male/female: 46/13) undergoing surgery at a single center were analysed. The median distance of the tumour from the dentate line was 5 cm. The operations performed were low anterior resection (n=45), Hartmann's procedure (n=4) and abdominoperineal resection (n=10). Total mesorectal excision with R0-resection was accomplished in all but one patients. Histopathological regression was described in four grades (0-3) as defined by the Japanese Society for Cancer of the Colon and Rectum. Tumors were called major responsive when assigned to the regression grades 3 or 2, and minor or nonresponsive at regression grades 1 or 0. In total, 33 patients (55.9%) had a regression grade 2 or 3. Among them, 12 patients showed a pathological complete response without any residual cancer cell (20.3%). Seven out of 45 patients (15.5%) with sphincter-preserving surgery suffered from suture breakdown; they all had previously shown a major response of the resected tumor. Two of them died during the hospital stay.

While in general, patients undergoing neoadjuvant intensified treatment suffer from a slight increase in surgical complications, this is markedly enhanced in patients with good treatment responses. Our results underline the oncological benefit of intensified neoadjuvant chemoradiation, but the severity of complications in low rectal anastomosis of patients with good response after neoadjuvant therapy should alert surgeons and oncologists.