The effect of postoperative pelvic irradiation after complete resection of metastatic rectal cancer.

BACKGROUND AND OBJECTIVES

The 2010 NCCN clinical practice guidelines recommend radiation as a part of the standard adjuvant or neoadjuvant treatment for stage IV rectal cancer patients. This study evaluated the oncologic efficacy of postoperative radiotherapy (RTx) in loco-regional control after complete removal of primary and metastatic lesions in stage IV rectal cancer.

METHODS

Sixty-eight patients with metastatic rectal cancer were enrolled and analyzed. Twenty-eight of the enrolled patients received concurrent postoperative RTx with chemotherapy (RTx group) and the remaining 40 received only postoperative systemic chemotherapy (CTx) without RTx (non-RTx group). The eligibility criteria were as follows: a primary rectal tumor located in the low or mid-rectum, no postoperative macroscopic and microscopic evidence of residual tumor in primary and metastatic sites, and no history of prior CTx or pelvic RTx.

RESULTS

The recurrence rates were 75.0% in the RTx group and 72.5% in the non-RTx group. Local recurrence rates were 7.1% (RTx group) and 22.5% (non-RTx group) (P = 0.108). There were no differences in overall survival (OS), local recurrence-free survival, and disease-free survival between the two groups. The 2-year OS rates were 78.9% (RTx group) and 74.1% (non-RTx group) (P = 0.395).

CONCLUSIONS

Survival benefit of postoperative RTx in stage IV rectal cancer after complete removal of tumors was not apparent. RTx could be recommended for selected patients at high risk of local recurrence or for palliation of symptoms.