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

ABSTRACT

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.