Screening Continues to Evolve in Prostate Cancer

Marc A. Bjurlin, DO

Optimal screening in prostate cancer remains a work in progress, notes Marc A. Bjurlin, DO, particularly with the utilization of active surveillance and prostate-specific antigen (PSA) testing shifting due to updated collaborative guidelines from ASCO, AUA, ASTRO, and SUO released in 2017.

Investigators are also beginning to conduct biomarker-driven studies to better risk-stratify patients who may or may not need active treatment for their disease.

“Biomarkers are coming down the pipeline,” said Bjurlin. “It is important to understand what the indications and limitations are and who are the appropriate patients to employ them. It is also important for physicians to understand what these biomarkers are, what stage in clinical care we can employ them, who is an appropriate candidate to avoid a biopsy, and who can undergo a biopsy.”

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In an interview during the 2018 OncLive^® State of the Science Summit^TM on Genitourinary Cancers, Bjurlin, a clinical assistant professor in the Department of Urology, NYU Langone’s Perlmutter Cancer Center, discussed ongoing efforts to optimize prostate cancer screening.Bjurlin: The way that we screen and detect prostate cancer has changed significantly over the last several years. Traditionally, we have screened men with PSA serum blood tests and have found that there is quite a low specificity for detecting prostate cancer. As a result, we had an overdiagnosis and overtreatment of low-grade prostate cancer that [may] never hurt a patient or affect their longevity.

Recently, there have been many emerging biomarkers that allow us to better risk-stratify men who may be at risk for prostate cancer. That allows us to counsel men on who would be appropriate to undergo a prostate biopsy because their risk of cancer may be significant. At the same time, it may allow us to educate men on who should avoid undergoing a prostate biopsy.

What are some ongoing clinical trials that are exploring biomarkers?

In the future, will PSA testing continue to have a role in the diagnosis of prostate cancer?

What patient characteristics warrant active surveillance versus active treatment?

What is the role of MRI-guided biopsy and how will that technology advance the field?

These new markers are serum-based or urine-based and allow us to look at the overall cancer detection rate. Other markers help define which men have risk of clinically significant disease and will ultimately benefit from treatment. There are many multi-institutional trials validating upcoming biomarkers. Some of them are in the development phase but there are several that have been completed and have been recently published. This shows promising results to help risk-stratify men who may be at risk for prostate cancer.Currently, a PSA test is a guideline-recommended first-line screening option for men who may be at risk for prostate cancer. Initially, these emerging biomarkers were indicated for men who have already had a negative biopsy and may be at risk for developing prostate cancer. Now, it has moved into the patient who has an elevated PSA. In the future, we will have a new test that is more specific than PSA to replace it.The updated guidelines suggest that men should be appropriately risk-stratified. Based on the aggressiveness of the prostate cancer, traditionally defined by a Gleason score, it is recommended that low-risk patients receive active surveillance. Those men who are at intermediate risk would benefit from treatment; however, the patient’s overall comorbidity status, their longevity, and patient preferences play a large role in what treatment option they may or may not undertake. It remains that men with high-risk prostate cancer benefit from treatment, given the appropriate longevity. The whole advent of MRI ultrasound fusion-targeted biopsy has changed the way we do our biopsy and the way we risk-stratify patients. Prior to the advent of MRI with transrectal ultrasound, we could not see prostate cancer. As a result, we did a random systematic biopsy of the prostate. We would take 6 biopsies from the left and right side of the prostate, giving us good distribution of biopsies to detect the cancer if it was there.

Over the time, we discovered that we missed a number of cancers, particularly high-grade cancers that should have been detected earlier. MRI has allowed us to visualize areas that are suspicious in the prostate. There is a grading system called the Prostate Imaging Reporting and Data System (PI-RADS) based on a 1 to 5 scoring system—1 being a normal prostate and 5 being the highest-risk lesion. A radiologist will interpret the MRI, assign it a PI-RAD score, and then use the MRI ultrasound fusion technology to see the abnormal area on a fusion overlay. Then, we could put needles specifically into the abnormal areas seen on the MRI, which has shown that we now increased the rate of detecting clinically significant disease and avoid the rate of missed biopsy on initial biopsy.