A team from England investigated the use of adjuvant radiotherapy for rectal cancer.
The Colorectal Cancer Collaborative Group conducted a meta-anlysis of 22 randomized, controlled trials that compared the outcomes of surgery combined with preoperative (6350 patients in 14 trials) or postoperative radiotherapy (2157 patients in 8 trials), with those of surgery alone.
Overall survival was only marginally better in patients who were allocated to radiotherapy, than in those allocated to surgery alone (62% vs 63% died).
|Deaths from rectal cancer:|
Preoperative radiotherapy: 45%
Surgery alone: 50%
The researchers found that rates of apparently curative resection were not improved by preoperative radiotherapy (85% radiotherapy vs 86% control).
Yearly risk of local recurrence was 46% lower in those who had preoperative radiotherapy than in those who had surgery alone. It was 37% lower in those who had postoperative treatment compared to those who had surgery alone.
Fewer patients who had preoperative radiotherapy died from rectal cancer than did those who had surgery alone (45% vs 50%, respectively). However, early (≤1 year after treatment) deaths from other causes increased (8% vs 4% died).
The authors commented that preoperative radiotherapy (at biologically effective doses ≥30 Gy) reduces risk of local recurrence and death from rectal cancer.
If safety can be improved without compromising effectiveness, then overall survival would be moderately improved by use of preoperative radiotherapy, especially for young, high-risk patients, they added.
Postoperative radiotherapy also reduces local recurrence, but short preoperative radiation schedules seem to be at least as effective as longer schedules, the group concluded.