Trends of prostate cancer treatment in Ehime Prefecture, Japan: analysis of a hospital-based cancer registry.

Background: We previously conducted a retrospective Japanese cohort study of patients who underwent radical prostatectomy (RP) between January 2010 and December 2020 in Ehime Prefecture. This study revealed an increase in the number of RP, but other treatment trends remained unclear. In the current study, we examined prostate cancer treatment in Ehime Prefecture using the hospital-based cancer registry of all designated cancer care hospitals and community cancer care hospitals belonging to the Council of Ehime Cancer Care Hospitals.

Methods: Trends of prostate cancer were compared by year according to stage and treatment using data from the hospital-based cancer registry between 2011 and 2020.

Results: The number of patients with stage 1 disease increased over time, but the proportion of patients with stage 1 disease among all patients decreased from 65.2% in 2012 to 56.9% in 2020. The number of patients with stage 2 disease also increased, but the proportion of such patients among all patients remained constant. Meanwhile, the proportions of patients with stage 3 or 4 disease increased significantly over time, while that of patients undergoing RP increased from 29.2% in 2011 to 45.7% in 2020 (P < 0.001). The proportion of patients receiving radiotherapy (RT) decreased from 25.8% in 2011 to 17.2% in 2020. The use of hormone therapy (HT) remained unchanged, and the proportion of patients undergoing observation fell from 11.0% in 2011 to 7.0% in 2020. A higher proportion of patients with stage 3 cancer received HT, and RT was more frequently used in stage 3 cancer than in stage 1-2 cancer. The use of HT increased with age.

Conclusions: The data highlighted differences in prostate cancer stages and treatment over time. This information could be shared with both urologists and radiologists to improve treatment.