Physicians Perform Fewer Prostate Biopsies Post-Phi Testing

Prostate cancer is the third-leading cause of cancer death in men, with one in seven receiving a diagnosis during his lifetime. In 2017, approximately 161,360 new cases of prostate cancer were identified, with 60% of those occurring in men 65 years of age or older.

Common methods for detecting prostate cancer include digital rectal exam (DRE) and the serum total prostate-specific antigen (PSA), followed by biopsy and transrectal ultrasound for final diagnosis. In recent years, however, the use of PSA screening for prostate cancer has come under scrutiny, with concerns that an increasing number of false-positives were leading to unnecessary invasive procedures.

Scientists collaborating with Carolina Urology Partners (Huntersville, NC, USA) carried out a prospective, observational study to determine if the use of Prostate Health Index (phi) testing changes physician behavior patterns when comparing their biopsy recommendations to a historical control group of similar patients seen by the same physicians. Patients for whom a participating urologist requested a phi test were recruited at the time of blood draw for the prospective (observational) study group. Inclusion criteria: men ≥50 years of age with total serum PSA between 4–10 ng/mL and non-suspicious DRE findings.

The Prostate Health Index (phi) (Beckman Coulter, Brea, CA, USA) is a calculation that uses a combination of three blood tests to produce a "phi score." This score provides more information about what elevated PSA levels might mean and the probability of finding prostate cancer on biopsy. The psi test comprises of three tests, PSA, free PSA, and p2PS.

The team reported that men receiving a phi test showed nearly a 24% reduction in biopsy procedures performed compared to the historical control group (36.4% versus 60.3%). Furthermore, physicians reported that the phi score significantly impacted their patient management plan in over 73% of cases, including biopsy deferrals when the phi score was low, and decisions to perform biopsies when the phi score indicated an intermediate or high probability of prostate cancer (phi≥36).

Michael Samoszuk, MD., chief medical officer, Beckman Coulter Diagnostics, said, “The phi test provides more information about the probability that a patient may have prostate cancer, giving both the patient and doctor additional insight to guide a decision as to whether a prostate biopsy is needed.” The study was published on November 20, 2017, in the journal Prostate Cancer and Prostatic Diseases.