Among patients with rectal cancer, delaying surgery for 11 weeks after the end of radiochemotherapy does not improve pathologic complete response rates, investigators reported.
Previously, the Lyon trial, the only randomized controlled study to investigate the effects of delaying surgery following the end of radiochemotherapy (RCT), found that compared with a 2-week delay, a 6-week delay significantly increased the number of patients who experienced complete response (53.1% vs. 71.7%, P = .007). The purpose of the current study was to evaluate the effect of a longer interval between RCT and surgery on pathologic complete response (pCR) rates.
For the phase III, multicenter, randomized trial, 265 patients with mid or lower rectal cancer were randomized to receive surgery at 7 weeks (n = 133) or 11 weeks (n = 132) following the end of RCT.
Baseline tumor characteristics and patient demographics were similar between the two study arms; the majority of patients had stage cT3 rectal cancer (82%).
There was no significant difference in pathologic complete response rate between the study arms (15% for 7-week group vs. 17.4% for 11-week group, P = .5983), reported Jeremie Lefevre, MD, of Hopital Saint-Antoine, Paris, and his associates (J Clin Oncol. 2016 July. doi: 10.1200/JCO.2016.67.6049).
Overall morbidity was significantly increased in the 11-week group (44.5% v 32%; P = .04), primarily explained by an increase in medical complications (32.8% vs. 19.2%; P = .01), the investigators wrote.
The French Ministry of Health funded the study. Dr. Lefevre and seven of his associates reported serving in advisory roles, receiving financial compensation, or participating in the speakers bureau for multiple companies.
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