Biomarkers Help Distinguish Prostate Cancer from Prostatitis
The biomarkers PHI and PCA3 demonstrated high diagnostic accuracy in discriminating prostate cancer from prostatitis in re-biopsy candidates.
The prostate health index (PHI) and prostate cancer antigen gene 3 (PCA3) score helped differentiate prostate cancer from prostatitis in patients considered for re-biopsy, according to a new study. The results support a previous study by the researchers that found the same biomarkers beneficial at first biopsy.
Investigators led by Stefano De Luca, MD, of the University of Torino in Italy, assessed 252 patients scheduled for re-biopsy (following high PSA levels and negative digital rectal examination) with urinary PCA3 score, serum PHI, and percentage of free PSA (% fPSA). Just 8.7% of the men had a history of chronic prostatitis. Each patient then underwent transrectal ultrasound-guided re-biopsy in which at least 18 cores were taken.
According to results published online ahead of print in Urologic Oncology, 17.1% of the men were diagnosed with prostate cancer. Each biomarker yielded different results for negative versus positive biopsies, but only PCA3 and PHI showed a moderate benefit after analysis; %fPSA was not deemed helpful. The results even held for patients in the gray zone of PSA (4–10 ng/mL).
The investigators also examined the ability of each biomarker to distinguish other non-neoplastic lesions. PHI helped differentiate prostatitis and benign prostatic hyperplasia. None of the biomarkers, however, could distinguish prostate inflammation from high-grade prostate intraepithelial neoplasia.
Other tools are still needed to prevent unnecessary biopsies, according to the investigators. Considering the high incidence of histologic prostatitis, not only more specific biomarkers but also new radiologic techniques (such as multiparametric magnetic resonance imaging) are needed, they said.
Limitations of the study include its observational design and an unbalanced number of patients by histological pattern of inflammation.