Ten-year results of preoperative radiation followed by sphincter preservation for rectal cancer: increased local failure rate in nonresponders.

BACKGROUND

The primary objective of this study was to determine the long-term outcome of sphincter preservation with preoperative radiation therapy (RT) and surgical resection in the treatment of distal rectal adenocarcinoma.

PATIENTS AND METHODS

Between April 1988 and December 1996, 36 (cT2, n=9; cT3, n=27) patients with rectal adenocarcinoma were enrolled on a phase I/II trial of preoperative RT followed by surgical resection. All patients had distal tumors that were clinically judged to require an abdominoperineal resection and received preoperative RT (50.4 Gy) followed by surgery. The median follow-up was 94.5 months (range, 4-187 months).

RESULTS

Of the 35 patients in this study who underwent resection, 77% were able to undergo sphincter preservation after preoperative RT. The pathologic complete response rate for these patients was 14%. The 10-year rates of overall survival and local failure for patients undergoing sphincter preservation were 54% and 21%, respectively. The 10-year local failure was 26% in patients with cT3 disease who underwent sphincter preservation. All local failures in this study occurred in patients with cT3 disease undergoing sphincter preservation; however, none of the patients with cT3 disease that was downstaged by preoperative RT experienced local failure. In contrast, 10-year local failure was 67% in the patients with cT3 disease that was not downstaged by RT. Sphincter function was good or excellent in 85% of patients at the time of last follow-up.

CONCLUSION

This approach provides excellent long-term results in all patients with cT2 disease and those with cT3 disease that is downstaged by RT. However, patients with cT3 disease that is not downstaged by RT have an increased risk of local failure. These data underscore the impact of tumor response to radiation on long-term oncologic outcome.