Outcomes of Gleason Score ≤ 8 among high risk prostate cancer treated with 125I low dose rate brachytherapy based multimodal therapy

Purpose: To investigate the role of low dose rate (LDR) brachytherapy-based multimodal therapy in high-risk prostate cancer (PCa) and analyze its optimal indications.

Materials and methods: We reviewed the records of 50 high-risk PCa patients [clinical stage ≥ T2c, prostate-specific antigen (PSA) >20 ng/mL, or biopsy Gleason score ≥ 8] who had undergone 125I LDR brachytherapy since April 2007. We excluded those with a follow-up period <3 years. Biochemical recurrence (BCR) followed the Phoenix definition. BCR-free survival rates were compared between the patients with Gleason score ≥ 9 and Gleason score ≤ 8.

Results: The mean initial PSA was 22.1 ng/mL, and mean D90 was 244.3 Gy. During a median follow- up of 39.2 months, biochemical control was obtained in 72% (36/50) of the total patients; The estimated 3-year BCR-free survival was 92% for the patients with biopsy Gleason scores ≤ 8, and 40% for those with Gleason scores ≥ 9 (p<0.001). In Cox multivariate analysis, only Gleason score ≥ 9 was observed to be significantly associated with BCR (p=0.021). Acute and late grade ≥ 3 toxicities were observed in 20% (10/50) and 36% (18/50) patients, respectively.

Conclusion: Our results showed that 125I LDR brachytherapy-based multimodal therapy in high-risk PCa produced encouraging relatively long-term results among the Asian population, especially in patients with Gleason score ≤ 8. Despite small number of subjects, biopsy Gleason score ≥ 9 was a significant predictor of BCR among high risk PCa patients after brachytherapy.