Top Line: What are the differences in acute and late toxicity between moderate hypofractionation and standard hypofractionation specifically for high risk prostate cancer?
Trials comparing moderate hypofractionation and conventional fractionation for prostate cancer included mostly low and intermediate risk patients, and they usually treated the prostate. The randomized, phase 3 Prostate Cancer Study-5 trial focused exclusively on high risk disease. 329 patients with high risk prostate cancer were randomized to standard fractionation or moderate hypofractionation. Everyone received neoadjuvant, concurrent, and long-term adjuvant ADT. In the SF arm, they received 46 Gy in 23 fractions to the prostate and pelvic nodes with a sequential boost to a total of 76 Gy in 38 fractions. In the HF arm, they simultaneously received 68 Gy to the prostate and 45 Gy to the pelvic nodes all in 25 fractions. This study reports the toxicity outcomes from Prostate Cancer Study-5. The rate of acute grade 2+ GI toxicity was higher in the HF arm (25% v 15%). However, the rate of acute grade 2+ GU toxicity was similar (37% v 32%). There were very few grade 3 events in either arm. Differences in toxicity between arms dissipated over time and at 24 months, there was no difference in the rates of grade 2+ GI or GU toxicity.
TBL: Toxicity outcomes from the Prostate Cancer Study-5 trial show a slightly higher rate of acute toxicity with HF that fades shortly after treatment and no differences in late toxicity when compared to SF. | Niazi, Int J Radiat Oncol 2023
Trials comparing moderate hypofractionation and conventional fractionation for prostate cancer included mostly low and intermediate risk patients, and they usually treated the prostate. The randomized, phase 3 Prostate Cancer Study-5 trial focused exclusively on high risk disease. 329 patients with high risk prostate cancer were randomized to standard fractionation or moderate hypofractionation. Everyone received neoadjuvant, concurrent, and long-term adjuvant ADT. In the SF arm, they received 46 Gy in 23 fractions to the prostate and pelvic nodes with a sequential boost to a total of 76 Gy in 38 fractions. In the HF arm, they simultaneously received 68 Gy to the prostate and 45 Gy to the pelvic nodes all in 25 fractions. This study reports the toxicity outcomes from Prostate Cancer Study-5. The rate of acute grade 2+ GI toxicity was higher in the HF arm (25% v 15%). However, the rate of acute grade 2+ GU toxicity was similar (37% v 32%). There were very few grade 3 events in either arm. Differences in toxicity between arms dissipated over time and at 24 months, there was no difference in the rates of grade 2+ GI or GU toxicity.
TBL: Toxicity outcomes from the Prostate Cancer Study-5 trial show a slightly higher rate of acute toxicity with HF that fades shortly after treatment and no differences in late toxicity when compared to SF. | Niazi, Int J Radiat Oncol 2023