High-dose radiotherapy boosts biochemical control in Gleason 9–10 prostate cancer

In patients with clinically localized Gleason 9–10 prostate cancer, dose-escalated radiotherapy confers better biochemical disease-free survival (bDFS) and prostate cancer-specific mortality (PCSM) than conventional doses, a recent study has found.

A total of 476 patients participated in the study. Of these, 127 (Conv group; median age 71 years) underwent conventional-dose external beam radiotherapy, while the remaining 349 (HDRT group; median age 71 years) high doses of radiotherapy. Aside from bDFS and PCSM, outcomes also included overall survival (OS) and distant metastasis-free survival (DMFS).

The overall 5-year bDFS rate was 81.1 percent, which was significantly higher in the HDRT vs Conv group (85.2 percent vs 71.1 percent; p<0.0001). Multivariate Cox regression analysis found that HDRT patients had significantly better biochemical control than Conv counterparts (hazard ratio [HR], 0.448, 95 percent CI, 0.283–0.7081; p=0.0006).

Similarly, PCSM was better in the HDRT group, which showed a 2.75-percent rate at both 5 and 10 years. In comparison, 5- and 10-year PCSM rates in the Conv group were 4.3 percent and 9.1 percent, respectively.

In contrast, overall survival rates in the HDRT (94.6 percent at 5 years, 89.9 percent at 10 years) and Conv (93.9 percent at 5 years, 82.4 percent at 10 years; p=0.15) were not significantly different. The same was true for DMFS (HDRT: 94.4 percent at 5 years, 89.1 percent at 10 years; Conv: 89.6 at 5 years, 83.2 percent at 10 years; p=0.0916).

“The retrospective nature of the study confers limitations related to follow-up time. Moreover, the small sample size cannot reflect the entire population of patients with prostate cancer, which may limit the application of our findings,” the researchers said.