Investigation of risk factors for prostate cancer patients with bone metastasis based on clinical data.

It has not yet been determined whether certain types of prostate cancer with bone metastasis (M1b PC) are associated with a poor outcome. The present study retrospectively assessed the potential significance of various clinical data in predicting the outcome of M1b PC. The subjects were 104 patients who attended our hospital and received a diagnosis of M1b PC between January 1998 and December 2006. The age of the subjects ranged from 51 to 91 years (median 74). The observation period ranged from 4 to 122 months (median 43). The parameters investigated were T classification, N classification, Gleason score (GS), pre-treatment prostate-specific antigen (PSA) level, extent of disease (EOD) grade, alkaline phosphatase (ALP), lactate dehydrogenase (LDH), calcium and hemoglobin (Hb) levels and platelet count. The 5-year cause-specific survival rate was 56.6% and the 10-year cause-specific survival rate was 34.9%. Log-rank test and Cox univariate analysis identified the following factors with statistically significant differences: pre-treatment PSA level ≥192, N1, GS ≥8, EOD grade 3+4, high LDH, high ALP and low Hb. Multivariate Cox proportional hazard analysis identified the factors GS ≥8 and high LDH with significant differences. The hazard ratio was 4.967 and 2.728, respectively, and the probability value (P) was 0.029 and 0.004, respectively. When the subjects with GS ≥8 and high LDH were classified as the high-risk group, the 5-year cause-specific survival rate was 24.6%. The outcome was significantly poorer in this group (P<0.0001) than in the other group, which had a 5-year cause-specific survival rate of 67.7%. The present study showed that patients with M1b PC with GS ≥8 and high LDH have a very poor outcome and thus should be treated as a high-risk group requiring close follow-up.