MedicalResearch.com Interview with:
R. Jeffrey Karnes MD
Department of Urology, Mayo Clinic,
Rochester, MN 55905
MedicalResearch: What is the background for this study? What are the main findings?
Dr. Karnes: Cancer recurrence following radical prostatectomy is a concern for men undergoing definitive surgical treatment for prostate cancer. Approximately 20-35% of patients develop a rising prostate specific antigen following radical prostatectomy for clinically localized prostate cancer. PSA monitoring is an important tool for cancer surveillance; however, a standard PSA cutpoint to indicate biochemical recurrence has yet to be established. Over 60 different definitions have been described in literature. This variation creates confusion for the patients and clinicians. By studying a large group of patients who underwent radical prostatectomy at Mayo Clinic, we found that a PSA cutpoint of 0.4 ng/mL is the optimal definition for biochemical recurrence.
MedicalResearch: What should clinicians and patients take away from your report?
Dr. Karnes: In this study we attempted to find the optimal PSA cutpoint that would capture the patients most at risk of continued PSA rise and subsequent systemic progression. We found that 75% of the patients who met the cutpoint of 0.4 ng/mL continue to have a durable rise in PSA at 5 years. We also evaluated several other common definitions including those recommended by large urologic organizations. Cutpoints lower than our threshold may select patients who have an elevated PSA due to causes other than prostate cancer recurrence; thus would result in overdiagnosis and overtreatment. On the other hand, higher cutpoints or confirmatory cutpoints may in fact be more specific in choosing patients with cancer recurrence but would delay timely treatment. Cutpoint of 0.4 ng/mL achieves the ability to capture patients at risk of recurrence without risking overdiagnosis.
This is crucial as our healthcare transitions to a more value-based system. Conditions such as prostate cancer may transition under the care of primary care physicians. The heterogeneity that currently exists in the landscape of biochemical recurrence can be confusing. Using a single cutpoint would translate into the simplest definition, allowing timely referral to specialists.
MedicalResearch: What recommendations do you have for future research as a result of this study?
Dr. Karnes: There is no “one size fits all” model for something as complex as prostate cancer. We recognize that many factors affect the recurrence and progression of prostate cancer. There are ongoing research endeavors to characterize prostate cancer beyond the microscopic level. Epigenetic mapping and molecular analysis of these cancer cells can yield a world of information about their behavior. Currently, PSA testing is ubiquitous across the nation and the world; therefore, current definitions are based mainly on this parameter. With advances in technology, a combination of parameters including biochemical, pathologic, and molecular patterns may yield the most accurate definition of biochemical recurrence.
Published online: December 22, 2015
R. Jeffrey Karnes MD (2016). Study Identifies PSA Level Most Likely To Predict Prostate Cancer Recurrence