Since 1985, Mayo Clinic has been collecting and storing clinical, pathological and follow-up data on men who have undergone radical prostatectomies at its campus in Rochester, Minn.
Because Mayo Clinic is such a high-volume urologic surgery center — on average over the past five years, urologic surgeons at its three campuses have performed an annual total of more than 1,600 prostatectomies — it's possible to estimate morbidity and mortality associated with prostatectomy, monitor long-term outcomes, and investigate the best predictors of outcome.
Today, Mayo Clinic's radical prostatectomy registry includes more than 20,000 patients, making it one of the largest registries of its kind in the world. More than 18,000 of these patients were seen from 1987 and onward — the period during which PSA screening has been standard practice at Mayo. The other several thousand patients were seen at Mayo between 1966 and 1986; their data were retrospectively added to the registry when it was established. Abstractors prospectively maintain the registry by following up annually with patients after surgery.
In addition to these data, tissue samples also are collected at the time of surgery, enabling researchers to study potential biomarkers and associate them with clinical outcomes.
Contributing to this research are not only Mayo urologic surgeons but also Mayo investigators with expertise in molecular biology, bioinformatics, pathology and epidemiology. A diverse team of biostatisticians, postdoctoral fellows and many others also support this research and its translation into clinical applications.
Since the introduction of PSA screening, Mayo has seen fewer cases of lymph node-positive prostate cancer. Prostate cancer screening practices, which include the use of the PSA test when appropriate, enable detection of early-stage, treatable prostate cancer. Without judicious use of the PSA test, it's possible that clinically localized prostate cancer would not have been detected until it had metastasized; such cases are rarely considered curable.
After radical prostatectomy, prostate cancer recurs in only a small percentage of men. The vast majority of men tracked in the registry remain cancer-free. An analysis of 12,000 cases of radical prostatectomy from 1987 through 2004 shows systemic recurrence rates of 5.6 percent after 10 years and 8.2 percent after 15 years, with prostate cancer death rates of 2.9 percent after 10 years and 5.3 percent after 15 years. These outcomes are markedly better than the cure rates seen before PSA screening, supporting the sensible use of the PSA test.
Long-term side effects after surgery are rare. Multiple studies have demonstrated that high-volume centers have improved outcomes after radical prostatectomy. Mayo data from 1987 through 2004 show that few patients have severe urinary incontinence after surgery; less than 0.2 percent have gone on to have additional surgery for problematic leakage within one year. Furthermore, when preservation of nerve bundles is possible, most men are capable of erectile function after surgery with or without assistance.
Using patient tissue samples linked to data from the radical prostatectomy registry, Mayo clinicians and researchers are investigating new diagnostic and prognostic molecular markers for prostate cancer. Such research is likely to lead to more-reliable diagnostic tools and a better ability to personalize therapy.
The best screening and diagnostic tools available today — a combination of the PSA test, digital rectal examinations and core needle biopsies — miss some clinically significant cancers. "Further biomarker research will hopefully enable the development of a highly sensitive, highly specific, potentially noninvasive diagnostic test that can more reliably and effectively detect significant prostate cancer," says R. Jeffrey Karnes, M.D., a urologic surgeon at Mayo Clinic's campus in Rochester.
Separating cases of indolent cancer and aggressive cancer remains a clinical challenge. At Mayo Clinic, research based on data from the radical prostatectomy registry has already led to the identification of several promising biomarkers that are likely to prove useful in identifying patients with life-threatening prostate cancer. More aggressive treatment may be indicated for patients with high-risk cancers, while active surveillance may be sufficient for those with insignificant cancers.