NEW ORLEANS, LA USA (UroToday.com) - Prostate cancer (PCa) continues to be the leading non-cutaneous cancer in men. Identifying those who have increased risk for bone metastasis (BM) or death from disease is essential. Alkaline phosphatase velocity (APV) has been shown previously to predict overall survival (OS) and bone metastasis-free survival (BMFS) in an equal access military cohort of castrate resistant prostate cancer (CRPC) patients. The authors examined a similar cohort of patients from a high volume cancer center to determine whether increased alkaline phosphatase (AP) kinetics were predictive of OS or BM.
CRPC patients treated at Memorial Sloan Kettering Cancer Center between 1989 and 2010 were included into the study. All patients received androgen deprivation therapy (ADT) primarily, or for an increasing PSA after surgery for PCa. CRPC was defined as one rising PSA value after PSA nadir ≤ 4ng/ml and confirmed by a second rising PSA value with simultaneous documented testosterone levels < 50 ng/dL. APV was calculated from the slope of the linear regression plot of all AP values (> 2 values per patient) against time.
Out of 89 patients with CRPC, 17 (19%) experienced BM and 26 (29%) died. Patients with faster APV had significantly worse 5-year outcomes, including earlier progression to BM and poorer OS compared to those with slower APV. The previous military patient cohort study showed that APV was an independent predictor of study outcomes. However, the authors found in their current study that there was a strong correlation between both PSA doubling time (PSADT) and APV. This observation prevented simultaneous evaluation of both factors in multivariate analysis. Unadjusted Kaplan Meier analysis also showed that PSADT was predictive of BM and OS.
In conclusion, the authors showed that APV and PSADT were predictors of BM and OS in patients with CRPC. However, their relatively small sample size limited multivariate confirmation. Future work will include prospective studies with larger cohorts to clarify these findings.
Presented by Adam Metwalli at the American Urological Association (AUA) Annual Meeting - May 15 - 19, 2015 - New Orleans, LA USA
National Institutes of Health, National Cancer Institute, Bethesda, MD USA
Reported by Richard Ho (University of California-Irvine), medical writer for UroToday.com