Radiotherapies Plus Androgen Deprivation After Surgery for High-Risk Prostate Cancer
Posted: Friday, June 12, 2020
Combining prostate-bed radiotherapy and pelvic lymph node radiotherapy with long-term androgen-deprivation therapy (ADT), following radical prostatectomy for prostate cancer, was shown to be a well-tolerated regimen in the single-arm, phase II McGill 0913 study. It was reportedly the first study to prospectively test this combination’s efficacy, said Tamim Niazi, MD, of Jewish General Hospital, Montreal, Québec, and colleagues in Frontiers in Oncology.
“At a median follow-up of 5.2 years, there were no deaths or clinical progression,” the investigators noted. At 5 years, progression-free survival—the study’s primary endpoint—was 78%.
From 2010 to 2016, 43 patients at high risk for relapse after prostatectomy (pathologic Gleason 8+ or T3 disease) were treated per protocol, explained the team. Their median prostate-specific antigen level was 0.30 μg/L; postsurgery pathology indicated that 51% had positive margins, 40% had Gleason 8+ disease, 42% had involvement of the seminal vesicle, and 19% had involvement of the lymph nodes. They received long-term ADT for 24 months and prostate-bed and lymph node radiotherapies (44 Gy in 22 fractions) followed by a prostate-bed radiotherapy boost (22 Gy in 11 fractions).
“No comparison between the average or minimum self-reported quality of life at baseline, during ADT, nor after ADT, demonstrated a statistically significant difference,” said Dr. Niazi and co-investigators. However, “long-term hypogonadism was a substantial risk,” occurring in 24% of the study population. Smaller percentages experienced endocrine toxicity (while on ADT), long-term gynecomastia, and grade 2 acute and late urinary toxicities.
The study included patients at particularly high risk for subsequent disease progression, including those with pathologically involved lymph nodes. However, few treatment failures (22%) were observed at a median follow-up of more than 5 years. Further study is necessary to assess the benefit of this combination in this patient population.
Disclosure: The study authors’ disclosure information can be found at frontiersin.org.
