Up2020 schreef op 19 april 2017 20:37:
Dr. Loeb, assistant professor of urology and population health at NYU School of Medicine, New York, said she considers the laboratory biomarkers that are used to refine initial biopsy decisions very helpful because they provide additional information and have higher specificity than total PSA.
Dr. Eggener, who is associate professor of surgery at the University of Chicago Medicine, concurred. “The introduction of PSA screening led to a dramatic reduction in the number of men dying from prostate cancer, but also a large number of men diagnosed with cancers unlikely to ever cause problems and unlikely to benefit from immediate treatment,” he said. “These new screening biomarkers outperform PSA as they capture all or nearly all cancers that are destined to cause problems while limiting the proportion of men who undergo biopsy.”
Dr. Eggener noted that biomarker testing has also been helpful for limiting unnecessary repeat biopsies.
Scott Eggener, MD
Dr. Eggener
“Whereas in the past, biopsy would be done routinely in a patient with a previous negative biopsy and ongoing clinical suspicion for prostate cancer, these newer biomarker tests provide risk stratification that can help determine if repeat biopsy is warranted,” he said.
Even though there is strong scientific rationale underlying all of the biomarker tests and solid clinical data to support their use, there are economic challenges for their integration into clinical practice, Dr. Eggener said.
“If the biomarker tests were cheap and easy, then they would be considered for nearly every patient. But such routine use does not seem appropriate because some of these tests are expensive and for many patients the results may not influence the decision one way or another,” he said. “Undoubtedly, there are situations when the biomarkers are so powerful that it makes the decision relatively simple and easy. However, a significant proportion of men are left with the same uncertainty they had before the biomarker results were available.”
Individual differences in risk tolerance help explain why the biomarker tests do not have a more definitive influence on management decisions, said Dr. Eggener, offering the following example to illustrate this point:
A healthy 60-year-old man with a normal prostate exam and no family history of prostate cancer has a PSA of 5.0 ng/mL. The patient is told the probability of finding prostate cancer on biopsy is probably 30% to 40%, and the likelihood of finding high-risk disease is significantly lower. The 4Kscore is ordered.
“If the result shows the man has a 1% chance of high-grade disease, he would probably be confident foregoing biopsy while he probably would not hesitate to choose biopsy if the 4Kscore indicated a 60% chance of finding high-grade cancer. However, the threshold at which an individual might choose or decline biopsy will vary,” Dr. Eggener said.
“When the 4Kscore shows there is a 7% chance of having high-grade prostate cancer, some men will definitely want a biopsy, some will be certain they do not need it, and others will still hem and haw.”