Definitive radiotherapy for prostate cancer in norway 2006-2015: Temporal trends, performance and survival.

BACKGROUND More studies are needed to document nation-wide use and effectiveness of curative definitive radiotherapy (Def-RT) in the treatment of prostate cancer (PCa). PATIENTS AND METHODS For 38,960 men diagnosed with PCa without distant metastases from 2006 to 2015 data from the Norwegian Prostate Cancer Registry and a national radiotherapy database (NoRadBase) was analyzed. Overall survival and PCa-specific mortality were described comparing EQD-2 <74 Gy ("low-dose") with EQD-2 ≥74Gy ("escalated dose"). RESULTS Use of Def-RT decreased (27% to 24%) whereas the proportion of radical prostatectomies (RPs) increased (31% to 38%). In high-risk patients the use of RP doubled (18% to 36%), while the proportion of Def-RT remained stable (about 35%). Before 2010, almost a quarter of patients received low-dose Def-RT with gradual increase of escalated Def-RT thereafter. Escalated Def-RT was associated with significantly more favorable 10-year PCa-specific mortality (4.4% [95% CI: 2.7%-10.7%]) than observed after low- dose Def- RT (8.8% [95% CI: 6.2%-9.8%), with the most beneficial effects in high-risk patients. Our analyses indicated the need to expand the NoRadBase by consensus-based quality measures. CONCLUSION In this nationwide cohort, the overall use of Def-RT decreased slightly. In high-risk patients the provision of Def-RT remained stable and was accompanied by doubling of patients with RP and reduction of a "no curative treatment" strategy. Escalated dose Def-RT significantly reduced 10-year PCa-specific mortality compared to low-dose Def-RT. Aiming for cancer care equity national radiotherapy registries for PCa should regularly monitor data based on consensus-based quality measures enabling feedback to the responsible hospitals.