Quantifying the relationship between increasing life expectancy and non-prostate cancer mortality after radical prostatectomy

OBJECTIVE: To investigate the relationship between increasing life expectancy and non-prostate cancer (competing) mortality after radical prostatectomy. PATIENTS AND METHODS: We studied a single center sample of 6809 consecutive patients who underwent radical prostatectomy between 1992 and 2016 with a median age of 65 years and a median follow-up of 7.9 years. Multivariate competing risk analyses were performed with competing mortality as endpoint. Linear trends over the years of surgery for 5-year competing mortality rates and for mean ages were calculated using linear regression analyses. We estimated the number of live years gained over time using a heuristic model-based calculation: (hazard ratio year of surgery) (24 calendar years) * (hazard ratio age at surgery) (gained life years)=1. RESULTS: After controlling for age, non-prostate cancer mortality decreased significantly during the observation period. Accumulated over the 24 years, this decrease of mortality corresponded to the effect of 6.3 years of calendric age. Most of the decrease in non-prostate cancer mortality (predominantly attributable to non-cancer causes of death) was seen in patients aged 65 years or older (8.1 years gained), whereas there was only a marginal decrease in patients younger than 65 years (only one year gained). The decrease in non-prostate cancer mortality was accompanied by a slight increase of mean age at surgery (2.7 years) that did not nearly compensate the decreasing risk. CONCLUSION: Clinicians should be aware of the decreasing competing mortality risk in elderly candidates for radical prostatectomy in order to avoid undertreatment.