Urinary tract events after radical radiotherapy (RT) for prostate cancer according to pre-RT International Prostate...

To describe the risk of urinary tract events after radical radiotherapy (RT) according to pre-RT (IPSS) overall and within subgroups of prostate volume, type of RT, and use of neoadjuvant androgen-deprivation therapy (ADT), as men who undergo RT for prostate cancer have a risk of urinary tract events.

Men in the National Prostate Cancer Register of Sweden who underwent RT between 2018 and 2023 for whom IPSS was registered at diagnosis were included. The IPSS was stratified as: low, 0-7; moderate, 8-19; and severe, 20-35 points. Urinary tract events were defined as lower urinary tract symptoms, infections, and urological procedures after treatment and assessed based on International Classification of Diseases and Related Health Problems, 10th Revision codes and procedures in The Patient Register. Competing risk of cumulative incidence proportion of urinary tract events at 3 year after RT was computed according to the IPSS, prostate volume, type of RT, and use of neoadjuvant ADT.

Of the 4436 men included, 43% had mild, 44% moderate, and 13% severe pre-RT IPSS. Incidence of urinary tract events after RT was 19% at 3 years for men with mild IPSS, 28% for moderate IPSS, and 39% for severe IPSS. The association between IPSS and urinary tract events was observed within subgroups based on prostate volume, type of RT, and use of neoadjuvant ADT. A 5-unit increase in IPSS carried a 20% increased risk of having a urinary tract event within 3 years.

A higher pre-RT IPSS is an indicator of increased risk of urinary tract events after RT - both overall and within subgroups of prostate volume, type of RT, and use of neoadjuvant ADT.