Prostate health index (PHI) is an improved analysis that outperforms traditional PSA screenings in predicting clinically significant prostate cancer.
PHI also outperforms free/total prostate specific antigen percentage test to predict the probability of prostate cancer diagnosis.
The phi combines measurements of %fPSA(percent of protein-attached and protein-free PSA circulating in the bloodstream) and a subcategory of free PSA called pro-PSA, and is estimated to be 2.5 times more specific in detecting prostate cancer in patients than a PSA screening.
A specific phi benchmark level may help identify biopsy candidates and reduce over-detection of indolent prostate cancer.
In a study of 658 men who were 50 years of age or older with a biopsy-confirmed prostate cancer diagnosis, a final PSA between 4-10 ng/mL and a benign rectal examination: investigators evaluated prediction of clinically significant cancer aggressive histopathology based on pre-biopsy measures of pro-PSA, total PSA, fPSA, %fPSA and phi-phi outperformed PSA and %fPSA in predicting the presence of clinically significant prostate cancer and for improving prostate cancer detection.
In the above study a phi level of 27 for selecting men for prostate cancer biopsy, when total PSA is 4 to 10 ng/mL, can decrease unnecessary biopsies and reduce over-detection of indolent prostate cancer.
Using a phi level of 27, the 90 percent sensitivity cut-point, 18.8 percent of men could have been spared from undergoing prostate biopsy or over-diagnosis of non-aggressive disease.