Long-Term Results of Sequence of Hormonal Therapy Plus Whole-Pelvic or Prostate-Alone Radiotherapy in Prostate Cancer
In long-term follow-up of the phase III NRG/RTOG 9413 study reported in The Lancet Oncology by Roach et al, neoadjuvant hormonal therapy (NHT) plus whole-pelvic radiotherapy (WPRT) and prostate-only radiotherapy (PORT) plus adjuvant hormonal therapy (AHT) were associated with the highest rates of 10-year progression-free survival in patients with intermediate- or high-risk localized prostate cancer.
Initial results of the trial showed that NHT plus WPRT improved progression-free survival vs NHT plus PORT, WPRT plus AHT, and PORT plus AHT.
Study Details
In the 2 x 2 factorial trial, with hormonal sequencing and radiation field as the two stratification factors, 1,322 patients from 53 sites were randomly assigned 1:1:1:1 between April 1995 and June 1999 to receive either:
- NHT 2 months before and during WPRT, followed by a prostate boost to 70 Gy (NHT plus WPRT group),
- NHT 2 months before and during PORT to 70 Gy (NHT plus PORT group),
- WPRT followed by 4 months of AHT (WPRT plus AHT group),
- PORT followed by 4 months of AHT (PORT plus AHT group).
10-Year Progression-Free Survival
Median follow-up was 8.8 years for all patients and 14.8 years for surviving patients (n = 346). Progression-free survival differed significantly across all time points among the four treatment groups (P = .002). Estimated progression-free survival at 10 years was 28.4% in the NHT plus WPRT group, 23.5% in the NHT plus PORT group, 19.4% in the WPRT plus AHT group, and 30.2% in the PORT plus AHT group.
Late Toxicity
Bladder toxicity was the most common grade ≥ 3 late toxicity, occurring in 6% of the NHT plus WPRT group, 5% of the NHT plus PORT group, 7% of the WPRT plus AHT group, and (4%) of the PORT plus AHT group. Late grade ≥ 3 gastrointestinal adverse events occurred in 7% of the NHT plus WPRT group, 2% of the NHT plus PORT group, 3% of the WPRT plus AHT group, and 2% of the PORT plus AHT group.
The investigators concluded, “In this cohort of patients with intermediate-risk and high-risk localized prostate cancer, NHT plus WPRT improved progression-free survival compared with NHT plus PORT and WPRT plus AHT at long-term follow-up, albeit [with] increased risk of grade 3 or worse intestinal toxicity. Interactions between radiotherapy and hormonal therapy suggests that WPRT should be avoided without NHT.”
The study was funded by the National Cancer Institute.
Mack Roach III, MD, FACR, of the Department of Radiation Oncology, University of California San Francisco Helen Diller Family Comprehensive Cancer Center, is the corresponding author for The Lancet Oncology article.
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