Estimating the individual benefit of immediate treatment or active surveillance for prostate cancer after screen-detection in older (65+) men

A significant proportion of screen-detected men with prostate cancer is likely to be overtreated, especially in older age groups. We aim to find which groups of screen-detected older men (65+) benefit the most from Immediate Radical Treatment or Active Surveillance (AS) for prostate cancer, depending on age, screening history, health status and prostate cancer stage at detection. We used a microsimulation model (MISCAN) of the natural history of prostate cancer based on ERSPC data. Individual life histories are simulated with US comorbidity lifetables based on a random sample of MEDICARE data. Different screening histories are simulated and we count outcomes for men screen-detected from ages 66 to 72. For immediately treated men with low-risk disease ( T2a, Gleason 6) the probability of overtreatment ranges from 61% to 86% decreasing to between 37 and 46%, if they are assigned to AS. For intermediate risk men (T2, Gleason 3+4) overtreatment ranges from 23 to 60%, which reduces to between 16 and 31% for AS. For high risk men (T3, orGleason 4+3), overtreatment ranges from 11 to 51%. The disease stage at screen-detection is a critical risk factor for overtreatment. For low risk men, AS seems to significantly reduce overtreatment at a modest cost. For intermediate risk men, the decision between immediate treatment or AS depends on age and comorbidity status. Men screen-detected in a high risk disease stage may benefit from immediate treatment even beyond age 69. What's new? How can clinicians strike a balance between overtreatment and undertreatment? Large scale screening programs inevitably lead to overdiagnosis, and treatment of cancers that would never develop into life-threatening disease. These authors created a computer simulation of prostate cancer that considered age, screening history, cancer stage, and general health to calculate individualized risk of overtreatment. Unlike previous studies, this model included active surveillance as an option, in addition to immediate treatment. For low-risk men, active surveillance can reduce overtreatment, while for intermediate-risk men, personal factors such as age and comorbidity will determine whether treatment or surveillance is the preferred course.