49 Background: This study aimed to evaluate long-term outcomes of intensity-modulated radiation therapy (IMRT) combined with neoadjuvant (NA) hormonal therapy (HT) in Japanese patients with non-metastatic prostate cancer (NMPC). Methods: We retrospectively analyzed the data of 485 patients with T1-T4N0M0 adenocarcinoma of the prostate treated with IMRT combined with NA-HT. Of these patients, 32, 113, 250, and 90 patients were categorized into the low-, intermediate-, high-, and very high-risk groups, respectively, according to the NCCN risk classification. NA-HT was administered over a median duration of 6 months. In principle, 74 or 78 Gy in 2 Gy per-fraction were delivered to the prostate and seminal vesicles according to the risk. We did not administer adjuvant HT (A-HT) for any patient following the completion of IMRT. Salvage HT (S-HT) commenced when prostate-specific antigen (PSA) values exceeded 4 ng/mL. Results: The median follow-up period was 103.4 months, and the median PSA value at the initiation of S-HT was 5.1 ng/mL. In the low-risk group, the 8-year biochemical relapse-free survival, prostate cancer-specific survival, overall survival, and S-HT-free (SHTF) rates were 89.7%, 100.0%, 100.0%, and 96.7%, respectively. Those were 83.7%, 100.0%, 96.0%, and 94.3% for the intermediate-risk group, 64.5%, 97.8%, 87.0%, and 79.4% for the high-risk group, and 47.7%, 96.6%, 89.7%, and 53.3% for the very high-risk group, respectively. The estimated 8-year cumulative incidence rates of late gastrointestinal and genitourinary (grades 2–3) toxicity were 7.2% and 21.8%, respectively. We observed no grade 4 or higher toxicity. Conclusions: High-dose IMRT, combined with NA-HT and without A-HT under the early S-HT policy, achieved excellent survival outcomes with acceptable morbidities for a Japanese cohort with NMPC. Moreover, especially for high, and very high-risk patients, this approach could be a viable alternative to the uniform provision of long-term A-HT because more than the half of the patients maintained SHTF status over a period of 8-year after IMRT. Prospective trials are warranted to validate the findings of this study.
Favorable outcome of intraoperative radiotherapy to primary site in patients with metastatic prostate cancer suggests benefits of local therapy: Retrospective study of long-term outcomes in a single Japanese center
