Pre-operative Prostate Health Index (PHI) levels may predict early biochemical recurrence (BCR) in prostate cancer patients, according to a new study.
For the study, investigators led by Giovanni Lughezzani, MD, of Humanitas University in Milan, Italy, examined the value of the Beckman Coulter PHI, a blood test that measures total, free, and [-2]proPSA, to predict BCR. A total of 313 patients had the pre-operative test and subsequently underwent robot-assisted radical prostatectomy for clinically localized prostate cancer (PCa). Patients receiving neoadjuvant or adjuvant therapy were excluded. On biopsy, Gleason score was 6 in 55% of patients, 7 in 39%, and 8 or higher in 6%.
At final pathology, just 228 patients (73%) were observed to have organ-defined disease; 59 had extracapsular extension, 24 seminal vesicle invasion, and 11 lymph node invasion. The 2-year biochemical-free survival rates were 93% overall and 97% among patients with organ-confined cancer, according to findings published online ahead of print in Urologic Oncology. BCR was defined broadly as a rising total PSA of 0.2 ng/mL or more.
The researchers determined that the most significant PHI cutoff value to discriminate between patients with and without BCR was 82. The 2-year biochemical-free survival rate was 98% in patients with a pre-operative PHI level of less than 82 compared with 70% among patients with a PHI level of 82 or above.
“According to our findings, PHI level emerged as an independent predictor of BCR and was significantly more accurate than the currently used predictors of BCR, such as tPSA level, clinical/pathological category, and Gleason score, in both the pre-operative and the post-operative settings,” the investigators stated. They suggest PHI levels may be useful in evaluating the need for early adjuvant radiotherapy and determining follow-up schedules post-prostatectomy.
As a next step, the researchers urge further validation of the PHI in studies with larger, more diverse populations, other treatment modalities, and with follow-up longer than 2 years.