Hypofractionated radiotherapy schedule (H-RT) is a treatment schedule that delivers a total dose of radiotherapy in a shorter time and should be considered as a new practice standard for men with low-risk prostate cancer. It is as better as the conventional radiotherapy schedule (C-RT) in maintaining bowel, sexual and general quality of life (QOL) and also improves anxiety and depression in men.
NRG-RTOG 0415, a phase III non-inferiority trial compared two fractionation schedules for men with low risk prostate cancer. A total of 1,092 men from the United States, Canada, and Switzerland were randomly assigned to one out of two treatment schedules. Men on the first treatment arm received C-RT at 73.8 Gy in 41 fractions over the course of 8.2 weeks. Men on the second treatment arm received H-RT at 70 Gy in 28 fractions over the course of 5.6 weeks. 962 patients consented to participating in the QOL study.
Patients on both arms were assessed at baseline, 6, 12, 24, and 60 months through the Expanded Prostate Index Composite (EPIC) for bowel, urinary, sexual and hormone domains, the Hopkins Symptom Checklist (HSCL) measuring anxiety and depression, and the Eq5D measuring QOL. There were no statistically significant differences in arms at any point for HSCL and Eq5D as well as no differences in physician reported grade three or greater gastrointestinal or genitourinary adverse events (AEs). There were no statistically significant differences in change score between arms with respect to the EPIC domain scores, except at 12 months with the H-RT arm exhibiting a larger decline in the bowel domain. However, this decline did not meet the a priori threshold of an effect size of 0.5 for clinical significance.
EPIC compliance rates ranged from 89.7% at baseline, 66.0% at 1 year, 60.8% at 2 years, to 55.5% at 5 years and these rates were similar for the HSCL-25 and Eq5D.
Outcomes from NRG-RTOG 0415 support the evidence that H-RT should be considered standard of care and negates the argument that reduced treatment duration equates to clinically meaningful increased AEs and decreased QOL.