Radiation Oncology

70 Gy salvage prostate‑bed RT adds toxicity without benefit over 64 Gy

In SAKK 09/10, 350 men with biochemical recurrence after prostatectomy were randomized to 64 Gy versus 70 Gy prostate‑bed salvage RT without ADT. After 8.6 years’ median follow‑up, freedom from biochemical progression was identical at 8.7 years in both arms (HR 1.03, p=0.87). Clinical progression‑free survival, time to hormonal therapy, and overall survival were also similar between doses. Late genitourinary toxicity was comparable, but late grade ≥2 gastrointestinal toxicity was significantly higher with 70 Gy (p=0.015). 1

Ultrahypofractionated whole‑pelvis RT with HDR boost is well tolerated at 1 year

The HOPE phase 2 trial randomized 80 patients with unfavorable intermediate‑ to very high‑risk prostate cancer to conventional versus ultrahypofractionated whole‑pelvis RT, both with HDR brachytherapy boost. At 1 year, bowel function EPIC scores were noninferior with ultrahypofractionation versus conventional WPRT (90.6 vs 88.4; p=0.0016 for noninferiority). Bowel bother, overall bowel scores, and urinary EPIC subdomains did not significantly differ between arms. No late grade 3–5 GU/GI toxicities occurred with conventional WPRT, and only one late grade 3 GU event occurred with ultrahypofractionation. 2

Neoadjuvant nivolumab/ipilimumab before CRT primes locally advanced cervical cancer

In the COLIBRI phase II trial, 40 women with locally advanced cervical carcinoma received one cycle of nivolumab plus ipilimumab before standard chemoradiation, then nivolumab maintenance. Induction immunotherapy significantly increased the intratumoral CD8+/FOXP3+ ratio and proliferative CD8+ T‑cell density. The HOT 27‑gene immune activation score also rose significantly after combination immunotherapy. Objective response was 13% immediately post‑immunotherapy, increasing to 98% after chemoradiation, with 65% complete responses and 90% responses at treatment completion. 3

RT to oligoprogressive lesions on ICIs supports durable control in NSCLC

This multinational real‑world series included 103 NSCLC patients receiving RT to ≤5 oligoprogressive lesions while on immune checkpoint inhibitors. Median progression‑free survival after RT was 6.90 months and median overall survival was 23.46 months. Intermediate/high radiation doses and local response to RT were associated with improved local control and overall survival (p=0.005 and p=0.006–0.01). Visceral oligoprogressive sites treated with RT had better progression‑free survival (p=0.01). 4