Analysis of Radiotherapy Regimens and Timing in Rectal Cancer
Among patients with rectal cancer, delaying surgery following short-course radiotherapy yields similar outcomes.
Among patients with rectal cancer, delaying surgery following short-course radiotherapy yields similar outcomes compared with immediate surgery after short-course radiotherapy, according to a study published in The Lancet Oncology.1
Although previous research demonstrated that radiotherapy lowers the risk of local recurrence in patients with rectal cancer, the optimal radiotherapy fractionation and interval between preoperative radiation and surgery remains controversial.
To evaluate recurrence in patients receiving 3 different radiotherapy regimens, investigators enrolled 840 patients with adenocarcinoma of the rectum eligible for surgery and without distant metastases into a phase 3, non-inferiority trial (Stockholm III; ClinicalTrials.gov Identifier: NCT00904813).
Investigators randomly assigned 385 patients 1:1:1 to receive 5 × 5 Gy radiation dose with surgery within 1 week (short-course radiotherapy), after 4 to 8 weeks (short-course radiotherapy with delay), or 25 × 2 Gy radiation dose with surgery after 4 to 8 weeks (long-course radiotherapy with delay). They also randomly assigned 455 patients 1:1 to receive short-course radiotherapy with immediate surgery or short-course radiotherapy with delay to surgery.
Both short-course radiotherapy with delay (hazard ratio [HR], 1.44; 95% CI, 0.41-5.11) and long-course radiotherapy with delay (HR, 2.24; 95% CI, 0.71-.7.10; P = .48) were non-inferior to short-course radiotherapy with immediate surgery.
Median time to local recurrence was 33.4 months, 19.3 months, and 33.3 months with short-course radiotherapy, short-course radiotherapy with delay, and long-course radiotherapy with delay, respectively.
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Investigators observed acute radiation-induced toxicity in only 1 of the 357 patients who received short-course radiotherapy, in 7% of the 355 patients who received short-course radiotherapy with delay, and in 5% of the 128 patients who had long-course radiotherapy with delay.
Short-course radiotherapy with delay conferred a 39% lower risk of postoperative complications compared with short-course radiotherapy with immediate surgery (odds ratio, 0.61; 95% CI, 0.45-0.83).
- Erlandsson J, Holm T, Pettersson D, et al. Optimal fractionation of preoperative radiotherapy and timing to surgery for rectal cancer (Stockholm III): a multicentre, randomised, non-blinded, phase 3, non-inferiority trial. Lancet Oncol. 2017 Feb 9. doi: 10.1016/S1470-2045(17)30086-4 [Epub ahead of print]