TUESDAY, Nov. 1, 2022 (HealthDay News) – A shortened course of radiation therapy is safe and effective for patients with high-risk prostate cancer, according to a study presented at the annual meeting of the American Society for Radiation Oncology, held from Oct. 23 to 26 in San Antonio.
Tamim M. Niazi, M.D., from McGill University in Montreal, and colleagues conducted a multicenter, phase 3 trial in which 329 patients were randomly assigned (1:1) to receive either conventionally fractionated radiation therapy (76 Gy in 2 Gy per fraction to the prostate and 46 Gy delivered to the pelvic lymph nodes in 38 daily sessions) or hypofractionated radiation treatment (concomitant dose escalation of 68 Gy in 2.72 Gy per fraction to the prostate and 45 Gy in 1.8 Gy per fraction to the pelvic lymph nodes in 25 daily sessions). All patients received neoadjuvant, concurrent, and adjuvant androgen suppression (median duration, 24 months).
There were no significant differences in survival between the two radiation groups for any outcomes at seven years, including overall mortality (81.7 versus 82 percent; hazard ratio [HR], 0.92; 95 percent confidence interval [CI], 0.56 to 1.53; P = 0.76), prostate cancer-specific mortality (94.9 versus 96.4 percent; HR, 1.31; 95 percent CI, 0.46 to 3.78; P = 0.61), biochemical recurrence (87.4 versus 85.1 percent; HR, 0.89; 95 percent CI, 0.49 to 1.60; P = 0.69), distant metastatic recurrence (91.5 versus 91.8 percent; HR, 0.89; 95 percent CI, 0.41 to 1.90; P = 0.76), or disease-free survival (86.5 versus 83.4 percent; HR, 0.82; 95 percent CI, 0.47 to 1.46; P = 0.50).
Further, there were no significant differences in grade 3 or higher acute or delayed genitourinary and gastrointestinal toxicities at two years, and no new toxicities emerged. Neither arm had grade 4 toxicities.
“The long-term results confirm that high-risk prostate cancer patients can safely and effectively be treated with moderate hypofractionated radiation therapy,” Niazi told Elsevier’s PracticeUpdate. “Given that our study has seven years of follow-up, and we used the contemporary radiation fields and long-term androgen deprivation therapy, I don’t think there is a need for validating these results. I believe our results should establish 68 Gy in 25 fractions as a new standard approach.”