Decade-long trends in prostate cancer biopsy grade groups and treatment within a population-based registry.

ABSTRACT

OBJECTIVE: To assess changes in diagnosis prostate cancer (PCa) grade, biopsy and treatment approach over a decade (2011-2020) at a population level within a clinical quality cancer registry. PATIENTS AND METHODS: Patients diagnosed by prostate biopsy between 2011 and 2020 were retrieved from the Victorian Prostate Cancer Outcomes Registry, a prospective, state-wide clinical quality registry in Australia. Distributions of each grade group (GG) proportion over time were modelled with restricted cubic splines, separately by biopsy technique, age group and subsequent treatment method. RESULTS: From 2011 to 2020, 24 308 men were diagnosed with PCa in the registry. The proportion of GG 1 disease declined from 36-23%, with commensurate rises in GG 2 (31-36%), GG 3 (14-17%) and GG 5 (9.3-14%) disease. This pattern was similar for men diagnosed by transrectal ultrasonography or transperineal biopsy. Patients aged <55 years had the largest absolute reduction in GG 1 PCa, from 56-35%, compared to patients aged 55-64 (41-31%), 65-74 (31-21%), and ≥75 years (12-10%). The proportion of prostatectomies performed for patients with GG 1 disease fell from 28% to 7.1% and, for primary radiation therapy, the proportion fell from 22% to 3.5%. CONCLUSION: From 2011 to 2020, there has been a substantial decrease in the proportion of GG 1 PCa diagnosed, particularly in younger men. The percentage of interventional management performed in GG 1 disease has fallen to very low levels. These results reflect the implementation of major changes to diagnostic and treatment guidelines and inform the future allocation of treatment methods.