OBJECTIVE: Validation in clinical practice, after first-line chemotherapy (CT) of metastatic castration-resistant prostate cancer (PC), of prostate-specific antigen growth rate constant logarithm (PSA-G), calculated by a formula developed by Stein et al. in comparison with PSA decrease (PSA-D), calculated as recommended by PCWG2.
PATIENTS AND METHODS: This study is a retrospective monoinstitutional assessment of PSA-G and PSA-D after 12 weeks from the beginning of first-line cytotoxic CT in 49 patients with metastatic castration-resistant PC treated from 2006 to 2011, and whose pre-CT PSA and post-CT PSA determinations have been measured at specific time points. The 12-week PSA was measured at 80 to 91 days from the beginning of CT.
RESULTS: PSA-G exhibited a significant correlation with overall survival by Mann-Whitney U test and by linear regression, whereas PSA-D did only at the first test. After multivariate analysis, PSA-G was the only posttreatment measure to predict overall survival.
CONCLUSION: PSA-G appears a reliable surrogate end point after first-line cytotoxic CT outside of clinical trials. A cutoff value of PSA-G post-CT higher than-2.4 could be considered suggestive for moving to another treatment.
Written by:
Colloca G, Venturino A, Addamo G, Ratti R, Coccorullo Z, Caltabiano G, Viale G, Guarneri D. Are you the author?
Division of Medical Oncology, "G. Borea" Hospital, Sanremo, Italy.
Reference: Urol Oncol. 2013 Nov 13. pii: S1078-1439(13)00202-0.
doi: 10.1016/j.urolonc.2013.05.002
PubMed Abstract
PMID: 24239469
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