Linking patient data to gain new insights
They matched participants with Medicare claims data and found 75 percent of the PCPT participants were in the Medicare system. The researchers, who included Dr. Ian Thompson Jr. of CHRISTUS Santa Rosa Hospital, Dr. Dawn Hershman of Columbia University Medical Center, and Drs. Scott Ramsey and Catherine Tangen of Fred Hutch, then created an algorithm to flag PCPT participants on Medicare who’d been diagnosed with and/or treated for prostate cancer.
A total of 3,244 PCPT participants developed the disease in the 16 years since the initiation of the original trial: 1,805 of those received placebo and 1,439 had taken finasteride. Overall, researchers found men who’d taken finasteride had a 21 percent decreased risk of getting prostate cancer over the course of 16 years compared to those who took placebo.
“These findings raise the intriguing possibility that seven years of finasteride can reduce prostate cancer diagnoses over a much longer period than was previously shown,” Unger said. “It’s a low-cost generic drug, with minimal side effects, that can have a benefit that lasts long after men stop taking it.”
Side effects of finasteride include decreased libido, impotence, and decreased ejaculate volume. Potential side effects of prostate cancer treatment, according to Fred Hutch’s clinical care partner Seattle Cancer Care Alliance, include infertility, incontinence, reduced libido, decreased ejaculate volume, and impotence.
The innovative design of this newly published, NCI-funded study was also notable, Unger said. By tapping Medicare claims data, the researchers could examine outcomes for trial participants many years after the original clinical trial had ended to answer new questions regarding reduction of cancer risk.
“These secondary data sources are emerging as a new paradigm for long-term follow up for cancer clinical trials,” he said. “It’s an exciting new avenue of research.”