The diffusion of robotic surgery technology has coincided with a rapid period of growth in surgical treatment of prostate cancer, and this has raised questions of whether technology adoption is driving overtreatment of prostate cancer. I study the relationship between regional robotic surgery adoption and the rates of treatments for prostate cancer patients using cancer registries from 2000-2008. Robotic surgery adoption accounts for 37-73 percent of increased age-adjusted surgery rates, and this is largely substitution away from radiation therapy. However, robotic surgery adoption explains only 12-24 percent of the increased total surgical volume. I show that, instead, two population trends account for 58-74 percent of the growth in surgery volume: (1) the demographic shift due to the aging of the baby boomer generation and (2) the earlier diagnosis of prostate cancer in younger patients, who are generally better candidates for surgery. In related work based on data on hospital prostatectomy volume, showed how diffusion of robotic surgery is correlated with strong growth in the market share of adopters, exit of small volume hospitals from the procedure market, and market consolidation among large-volume providers, whose collective market share nearly doubled from 2003 to 2009. Based on procedure-specific Herfindahl indices, prostatectomy markets, which once more closely resembled hysterectomy markets, now more closely approximate the concentration of cardiac surgery markets.