The Prostate Health Index (phi) Limits the Need for Additional Biopsies

A low-cost test, The Prostate Health Index (phi) that is used to detect prostate cancer can limit the number of repeat biopsies that Urologists recommend. It also reduces the risk of over diagnosis, saves money and cuts down on the risk of biopsy-induced infections. 

Jay White of Carolina Urology Partners, lead author of a study published in the Journal Prostate Cancer and Prostatic Diseases confirmed this finding.  The study included urologists from four large specialized practices across the US.   The study is the first one to consider the value of the index within a multi-center private practice setting.

The phi is designed to assist a doctor and patient in deciding the need for a biopsy.   This decision becomes especially tricky when a blood test shows that a man has an elevated level of prostate-specific antigen (PSA) but their digital rectal exam (DRE) shows nothing suspicious. 

Over two-thirds of such biopsies are typically found to be benign when the man’s PSA level ranges from 4 to 10 nanograms per milliliter (ng/mL). 

The phi test, a product of Beckman Coulter, was approved by the US Food and Drug Administration (FDA) in 2012.  Its approval is to aid in the diagnosis of prostate cancer for men presenting with total PSA levels from 4 to 10 ng/mL and non-suspicious DRE findings. 

It combines the results of three quantitative kallikrein immunoassays (total PSA, free PSA, and p2PSA) into a single numerical phi score. Other studies have also shown that elevated phi scores are associated with higher-grade prostate cancers.

In White’s multi-center study, White and his colleagues used a two-part questionnaire to find out whether phi scores influence a physician's decision to perform a biopsy or merely monitor their patients further. In a second part of the study, the biopsy procedures conducted on 506 men were compared to that of a similar group of 683 men who visited the practices before the test had been implemented. 

The study found that in 73 percent of the men, the phi scores were found to influence doctors' decisions about how to manage their patients. Only 36 percent of men received biopsies when phi testing was included in the assessment, compared to the 60 percent who had to undergo such procedures before the index was available. There was also an overall reduction in the percentage of low-grade prostate cancers detected.

"Physicians were less inclined to do a biopsy on patients receiving a low phi score, and more inclined to recommend biopsy for patients receiving an intermediate to high-risk phi score," explains White. "It also improved a physician's ability to communicate their recommendation to the patient, and helped alleviate patient anxiety in cases where the phi score was low."

"The appropriate use of the Prostate Health Index can significantly modify physician behavior patterns and improve their ability to diagnose and manage their patients," adds White.

Joel T. Nowak, MA, MSW wrote this Post.  Joel is the CEO/Executive Director of Cancer ABCs.  He is a Cancer Thriver diagnosed with five primary cancers - Thyroid, Metastatic Prostate, Renal, Melanoma, and the rare cancer Appendiceal cancer.