Postoperative complications in relation to overall treatment time in patients with rectal cancer receiving neoadjuvant radiotherapy.

BACKGROUND

The optimal timing of surgery for rectal cancer after radiotherapy (RT) is disputed. The Stockholm III trial concluded that it was oncologically safe to delay surgery for 4-8 weeks after short-course RT (SRT), with fewer postoperative complications compared with SRT with surgery within a week. Other studies have indicated that an even shorter interval between RT and surgery (0-3 days) might be beneficial. The aim of this study was to identify the optimal interval to surgery after RT.

METHODS

Patients were analysed as treated, in terms of overall treatment time (OTT), the interval from the start of RT until the day of surgery. Patients receiving SRT (5 × 5 Gy) were categorized according to OTT: 7 days (group A), 8-13 days (group B), 5-7 weeks (group C) and 8-13 weeks (group D). Patients receiving long-course RT (25 × 2 Gy) were grouped into those with an OTT of 9-11 weeks (group E) or 12-14 weeks (group F). Outcomes assessed were postoperative complications and early mortality.

RESULTS

A total of 810 patients were analysed (group A, 100; group B, 247; group C, 192; group D, 160; group E, 52; group F, 59). Baseline patient characteristics were similar. There were significantly more overall complications in group B than in groups C and D. Adjusted odds ratios, with B as the reference group, were: 0·72 (95 per cent c.i. 0·40 to 1·32; P = 0·289), 0·50 (0·30 to 0·84; P = 0·009) and 0·39 (0·23 to 0·65; P < 0·001) for groups A, C and D respectively. Early mortality was similar in all groups. There were no significant differences between long-course RT groups.

CONCLUSION

These results suggest that surgery should optimally be delayed for 4-12 weeks (OTT 5-13 weeks) after SRT.