(HealthDay News) — A targeted radiotherapy technique can substantially cut treatment time for prostate cancer without increasing gastrointestinal or genitourinary acute toxicity, according to a phase 3 study published online in The Lancet Oncology.

Douglas H. Brand, MD, from the Royal Marsden Hospital in the United Kingdom, and colleagues performed an acute toxicity substudy using data from an international, phase 3, open-label, randomized, noninferiority trial in which 874 men with low-risk or intermediate-risk prostate adenocarcinoma were randomly assigned to either conventionally fractionated or moderately hypofractionated radiotherapy (441 patients; 78 Gy in 39 fractions over 7.8 weeks and 62 Gy in 20 fractions over 4 weeks, respectively), or stereotactic body radiotherapy (433 patients; 36.25 Gy in 5 fractions over 1 to 2 weeks).

The researchers found that worst acute Radiation Therapy Oncology Group (RTOG) gastrointestinal toxic effect (at least grade 2 severe toxic events) occurred in 12% of the patients in the conventionally fractionated or moderately hypofractionated radiotherapy group and in 10% of the patients in the stereotactic body radiotherapy group (difference, −1.9 percentage points; 95% confidence interval, −6.2 to 2.4; P=0.38). Worst acute RTOG genitourinary toxicity occurred in 27% of patients in the conventionally fractionated or moderately hypofractionated radiotherapy group versus 23% of patients in the stereotactic body radiotherapy group (difference, −4.2 percentage points; 95% confidence interval, −10.0 to 1.7; P=0.16). No treatment-related deaths were reported.

“Our results suggest that substantially shortening treatment courses with stereotactic body radiotherapy does not increase either gastrointestinal or genitourinary acute toxicity,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

Reference

Brand DH, Tree AC, Ostler P, et al. Intensity-modulated fractionated radiotherapy versus stereotactic body radiotherapy for prostate cancer (PACE-B): acute toxicity findings from an international, randomised, open-label, phase 3, non-inferiority trial. Lancet Oncol.