Lag time to adverse events after radical prostatectomy and curative radiotherapy

49 Background: Men who are curatively treated with radiotherapy (RT) or radical prostatectomy (RP) for localized prostate cancer have long life expectancy but data on long term complications to treatment are scarce. Methods: In the nationwide, population-based Prostate Cancer data Base Sweden (PCBaSe), we identified men who underwent RT or RP between 1997 and 2012. Date of radiotherapy and dose of radiation were reassessed in an audit. For each case five controls from the background population, matched for age and county of residence, had been identified. The National Patient Register was used to identify diagnoses and surgical procedures indicating a complication to treatment, such as urinary incontinence, lower urinary tract symptoms and gastrointestinal symptoms, up to twelve years after treatment. The incidence rate ratio of complications for men who received RT and RP relative to their matched controls was calculated and relative risks (RR) were calculated for RT vs RP adjusted for treatment year, age, Charlson comorbidity index, educational level, PSA-level, clinical T stage and biopsy Gleason score. Results: In total, 37,420 men met the study criteria, of whom 12,534 had undergone RT and 24,886 had undergone RP. There were 186,624 matched controls. The risk of receiving any of the analyzed diagnoses or surgeries at 12 years after treatment was higher after RT; RT vs RP RR 1.20 (95%CI 1.08-1.34) and RT vs RP RR 1.49, (95% CI 1.36-1.64) for the diagnoses and surgical procedures respectively. At 3 years the risk of receiving any of the analyzed diagnoses was comparable between the treatments; RT vs RP RR 1.02 (95% CI 0.91-1.16) but the risk of undergoing any of the analyzed surgical procedures remained higher after RT during the entire study period. Men who underwent RP had a higher risk of being diagnosed or treated for urinary incontinence; RT vs RP RR 0.09 (95% CI 0.04-0.19) and RR 0.04 (95% CI 0.01-0.11) for the selected diagnoses and surgical procedures respectively. Conclusions: Complications after RP mostly occurred within the first 3 years after surgery whereas complications after RT were more frequent at a later date after treatment.