A molecular signature predictive of indolent prostate cancer

New concepts concerning prostate cancer screening

Prostate Cancer (CaP) is rapidly becoming a worldwide health issue. While CaP mortality has decreased in recent years, coincident with the widespread use of Prostate-Specific Antigen (PSA) screening, it remains the most common solid tumor in men and is the second leading cause of cancer death in the United States. The frequency of CaP is growing not only in western cultures, but also its incidence is dramatically increasing in eastern nations. Recently, examination of data from long-term trials and follow up has cast a shadow on the effectiveness of employing PSA as a primary screening tool for CaP. In this review, we not only summarize opinions from this examination and synthesize recommendations from several groups that suggest strategies for utilizing PSA as a tool, but also call for research into biomarkers for CaP diagnosis and disease progression. We also describe our recent work that identified a smooth muscle contractile protein in prostate epithelia, namely smooth muscle gamma actin, and indicate the potential for this molecule as a new unique footprint and as a CaP marker.

The prognostic significance of Gleason scores in metastatic prostate cancer

PURPOSE

Although the majority of metastatic prostate cancer (mPCa) will arise from tumors with Gleason scores (GS) of 8 to 10 existing tumor grade analyses for mPCa have been almost uniformly limited to comparisons of ≤7 vs. ≥8. In this analysis, we comprehensively evaluate the GS as a prognostic factor for mPCa in the era of the updated Gleason grading system.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried for patients with mPCa, GS 6 to 10, diagnosed from 2006 to 2008. GS and primary-secondary Gleason pattern variations were analyzed for overall survival and prostate cancer-specific survival (PCSS).

RESULTS

A total of 4,654 patients were evaluable. At 4 years, the overall survival rates were 51%, 45%, 34%, 25%, and 15% and PCSS rates were 69%, 57%, 44%, 33%, and 21% for GS 6, 7, 8, 9, and 10, respectively. Survival differences for GS 7 vs. 8, 8 vs. 9, and 9 vs. 10 were highly significant on both univariate and multivariate analyses accounting for age, prostate-specific antigen level, and T stage (all P<0.001). Gleason pattern 5 was an independent prognostic factor, both overall for patients with GS 6 to 10 and on primary-secondary Gleason pattern comparisons within the GS 8 (4+4 vs. 3+5 and 5+3) and GS 9 (4+5 vs. 5+4) subgroups. No survival differences were observed between 3+4 vs. 4+3. Overall, lower prostate-specific antigen level, younger age, and lower GS were associated with improved survival, with GS being the strongest prognostic factor for PCSS.

CONCLUSIONS

In this large population-based cohort, stratified survival outcomes were observed for GS 6 to 10, with sequential comparisons of GS 7 to 10, and the presence and extent of Gleason pattern 5 representing independent prognostic factors in the metastatic setting.