Presence of biopsy Gleason pattern 5 + 3 is associated with higher mortality after radical prostatectomy but not after external beam radiotherapy compared to other Gleason Grade Group IV patterns

Background We hypothesized that Gleason Grade Group (GGG) IV patients treated with radical prostatectomy (RP) or external beam radiotherapy (EBRT) exhibit different cancer‐specific mortality (CSM) rates according to underlying Gleason patterns (GP): 4 + 4 versus 3 + 5 versus 5 + 3. Materials and Methods We identified all GGG IV patients treated with either RP or EBRT within the Surveillance, Epidemiology, and End Results 2004–2016 database. The effect of biopsy GP on CSM (3 + 5 vs. 4 + 4 vs. 5 + 3) was tested in Kaplan–Meier and multivariable competing risks regression models (adjusted for PSA, age at diagnosis, cT‐, and cN‐stage). Results Of 26,458 GGG IV patients, 14,203 (53.7%) were treated with EBRT and 12,255 (46.3%) with RP. Of RP patients, 15.3 versus 81.2 versus 3.4% exhibited biopsy GP 3 + 5 versus 4 + 4 versus 5 + 3 and respective 10‐year CSM rates were 6.5 versus 6.2 versus 12.6% (p