Postoperative radiotherapy for stage IIIA rectal cancer: is it justified?

Adjuvant radiotherapy is currently recommended for all node-positive rectal cancers to reduce local recurrence. This study evaluated if an adequate mesorectal excision can obviate the need for radiotherapy in early node-positive cancer.

Stage IIIA rectal cancer patients were identified in a prospectively maintained database. Patients who received postoperative radiotherapy (radiotherapy) and those who did not (no radiotherapy) were compared for recurrence, survival, bowel function, and quality of life. Quality of life was assessed using the Short Form-36 Medical Outcomes Survey.

Eighty-six patients underwent proctectomy for T1-T2,N1 rectal cancers from 1978 to 2004. Patients receiving radiotherapy (n = 34) were younger and had a higher percentage of T1 tumors than patients who did not receive radiotherapy (n = 52). Other tumor characteristics, type of surgery, and number of involved lymph nodes were comparable. Estimated 5-year local recurrence was radiotherapy 3.4 percent and no radiotherapy 4.7 percent; distant recurrence was radiotherapy 13.5 percent and no radiotherapy 16.5 percent; and disease-specific mortality rates were similar 13.5 vs. 11.3 percent, for radiotherapy and no radiotherapy (all P > .05). Patients receiving radiotherapy had higher frequency of daytime bowel movements, urgency, and usage of pads and antidiarrheal medications. Age adjusted quality of life parameters were comparable between treatments.

Postoperative radiotherapy did not reduce recurrence or mortality. Function but not quality of life was adversely affected. Routine postoperative radiotherapy for Stage IIIA rectal cancer should be reconsidered.