Anal Cancer: IMRT Less Toxic Than Conventional RT

"Our primary end point was not met," said Dr. Kachnic, who reported having no conflicts of interest related to the trial. That is, the rate of grade 2 or higher acute gastrointestinal and genitourinary toxicities combined was essentially the same with IMRT and conventional radiation, at about 77% in each group.

The IMRT group did have significantly lower rates of grade 3 or higher acute gastrointestinal and genitourinary toxicities combined (P = .005), gastrointestinal toxicity alone (P = .008), and skin toxicity (P less than .0001), as well as a lower rate of grade 2 or higher acute hematologic toxicity (P = .03).

The IMRT and conventional radiation therapy patients had similar 2-year rates of efficacy outcomes, with overlapping 95% confidence intervals for locoregional failure (19% and 19%), colostomy failure (8% and 11%), colostomy-free survival (84% and 83%), disease-free survival (77% and 75%), and overall survival (86% and 91%).

"After short-term follow-up, IMRT appears to be as effective as conventional radiation in the treatment of anal cancer but with decreased side effects," commented Dr. Jennifer C. Obel, moderator of the presscast and a medical oncologist with the NorthShore University HealthSystem in Evanston, Ill. "By limiting treatment of nearby tissues, a patient’s quality of life is improved during treatment."

"While larger studies will need to be performed and longer follow-up is required, IMRT may emerge as a key treatment modality for anal cancers," noted Dr. Obel, who did not report any conflicts of interest.