Published in the Red Journal, this study from the Mayo Clinic reported outcomes of 56 patients with high-risk or unfavorable intermediate-risk treated with moderately hypofractionated IMPT. The prostate/seminal vesicles and pelvic lymph nodes were treated simultaneously with 67.5 Gy and 45 Gy, in 25 daily fractions. Median follow-up was 62 months.

This study reported that at 5-year, the late grade ≥ 2 and 3 GI adverse events were 16% and 4%; late grade ≥ 2 and 3 GU AEs were 41% and 0%; no grade ≥ 4 late AE; recurrence-free rate and disease-free survival were 90% and 89%, respectively.

The authors concluded that these results were encouraging, and a phase III study is needed to assess any therapeutic gain of IMPT compared with photon-based radiotherapy.