ORLANDO — For the first time since the advent of widespread prostate-specific antigen screening, identification of early-stage prostate cancers has begun to level off, Dr. Eric A. Klein said at a symposium on prostate cancer sponsored by the American Society of Clinical Oncology.
An analysis of prostate cancer detection trends among 3,364 men treated with prostatectomy at the Cleveland Clinic between 1987 and 2005 showed that the percentage of tumors that had spread beyond the prostate at the time of surgery decreased from 79% to 25%. However, this trend has now plateaued, said Dr. Klein, professor of surgery and head of urologic oncology at the Cleveland Clinic's Glickman Urological Institute. Since 1998, the percentage of tumors found to have spread beyond the prostate ranged from 25% to 36%.
Before prostate-specific antigen (PSA) testing, half of men initially diagnosed with prostate cancer had stage C or D disease—incurable cancer outside the prostate. Just 5 years after PSA screening was introduced, 95% of newly diagnosed prostate cancer was being picked up at a curable stage, Dr. Klein said at the symposium, cosponsored by the Society of Urologic Oncology and the American Society for Therapeutic Radiology and Oncology.
“The increase in prostate cancer survival rates that we have seen over the past 20 years is no doubt due to widespread PSA testing that has allowed us to detect cancers in their early, more curable stage,” he said. But now, the rise in rates of cure because of the likelihood of having an organ-confined disease has ended.
“We're not going to see gains in cure rates beyond what we've already achieved simply based on PSA screening. Additional increments in cure to 100% will require [truly] new therapeutic advances both in surgery and radiation therapy, and, I believe, in molecular agents,” Dr. Klein said.