Response to preoperative chemoradiation in stage II and III rectal cancer.

Purpose: The purpose of this study was to determine whether a complete pathologic response after neoadjuvant therapy in rectal cancer patients improves disease control and survival.

Methods: The study reviewed Stage II and III rectal cancer patients treated with preoperative chemoradiation and resected for cure. Complete pathologic response was defined as no cancer in the resected specimen. The main outcome measures were cancer-specific and disease-free survival in patients achieving a complete pathologic response and a noncomplete pathologic response. Kaplan-Meier curves were evaluated using log-rank analysis.

Results: Eighty-nine rectal cancer patients received neoadjuvant chemoradiation followed by radical resection for cure. Twenty-one patients (24 percent) achieved a complete pathologic response. Median follow-up for the complete pathologic response group was 23.5 months and 31 months for the noncomplete pathologic response group. There were more Stage III patients in the noncomplete pathologic response group than the complete pathologic response group (P = 0.005). Complete pathologic response patients were less likely to receive postoperative adjuvant chemotherapy than noncomplete pathologic response patients (P = 0.004). Cancer-specific and disease-free survival were not statistically different between the two groups. However, a trend was noted toward improved survival and decreased recurrence in association with a complete pathologic response.

Conclusion: Stage III patients were less likely to be in the complete pathologic response group than Stage II patients. Complete pathologic response patients were less likely to receive postoperative adjuvant chemotherapy than noncomplete pathologic response patients. Complete pathologic response after neoadjuvant chemoradiation for rectal cancer patients demonstrated a trend toward improved survival and decreased recurrence compared with noncomplete pathologic response patients.