Post-therapy serum prostate-specific antigen level and survival in patients with androgen-independent prostate cancer.

Scher, Howard I.; Kelly, W. M. Kevin; Zhang, Zuo-Feng; Ouyang, Peter; Sun, Min; Schwartz, Morton; Ding, Cliff; Wang, Weiping; Horak, Ivan D.; Kremer, Alton B.; Scher, H I; Kelly, W M; Zhang, Z F; Ouyang, P; Sun, M; Schwartz, M; Ding, C; Wang, W; Horak, I D; Kremer, A B

<bold>Background: </bold>With an hypothesis that post-chemotherapy changes in serum prostate-specific antigen (PSA) levels might serve as a surrogate marker for assessing prostate cancer outcome (i.e., survival), we studied the relationship between pretherapy and post-therapy prognostic factors and survival in patients with androgen-independent prostate cancer.<bold>Methods: </bold>A prognostic model for survival based on pretherapy and post-therapy parameters was developed from the clinical data on 254 patients with androgen-independent prostate cancer treated with 11 different protocol therapies at Memorial Sloan-Kettering Cancer Center. The model was validated by use of an independent dataset of 541 patients enrolled in two randomized phase III trials.<bold>Results: </bold>In multivariate analysis, a post-therapy decline in PSA levels of 50% achieved in 12 weeks was a statistically significant factor associated with survival (two-sided P = .0012). A similar outcome was obtained with the use of an 8-week time frame. Elevated pretherapy level of serum lactate dehydrogenase (two-sided P = .0001), lower pretherapy level of hemoglobin (P = .0001), and younger age (two-sided P = .0430) had a statistically significant negative impact on outcome. Median survival times were 23, 17, and 9 months for low-, intermediate-, and high-risk groups of patients defined by the prognostic model, respectively.<bold>Conclusion: </bold>This study confirms the prognostic value of a post-therapy decline in PSA of 50% or greater from baseline in relation to survival in patients with androgen-independent prostate cancer treated with a variety of therapies. Two consecutive determinations at 4-week intervals can be used as an end point for efficacy in phase II trials of therapies in this disease.

PROGNOSIS; PROSTATE cancer patients; ANDROGENS

JNCI: Journal of the National Cancer Institute, 1999, Vol 91, Issue 3, p244

0027-8874

Academic Journal

10.1093/jnci/91.3.244