Positive margin length and highest Gleason grade of tumor at the margin predict for biochemical recurrence after radical prostatectomy in patients with organ-confined prostate cancer.

BACKGROUND: To evaluate the pathologic features after radical prostatectomy to determine if the length of positive surgical margin (PSM) and the highest Gleason grade within the tumor at the PSM could risk stratify patients for biochemical recurrence (BCR). METHODS: We performed a retrospective, matched, cohort study to identify patients with pathologically organ-confined (pT2) tumors and negative nodes (pN0/Nx), receiving no adjuvant therapy. Specimens underwent single pathologist review. BCR-free survival was estimated using the Kaplan-Meier method and compared between subgroups using two-sided log-rank test. Using Classification and Regression Tree analysis (CART), we identified an optimal cutoff for the PSM length which differentiated risk for BCR. Cox proportional hazards regression models were fit to assess the association between variables and BCR-free survival. RESULTS: Two-hundred PSM patients were matched to 200 patients with negative surgical margins (NSM). Median follow-up was 64 months. 5 year BCR-free survival was 90% (95% CI 84-97%) in the NSM group and 70% (95% CI 63-79%) in the PSM group. There was an increased risk of BCR with any PSM. Multivariable analysis demonstrated an association with length of PSM ( > 1 mm vs. ≤ 1 mm, HR 2.29; 95% CI 1.2-4.5) and having a highest Gleason grade of the cancer focus at the margin ≥ 4 (HR 6.8; 95% CI 1.6-29). CONCLUSIONS: We demonstrated that patients with pathologic T2 tumors with PSM > 1 mm or a Gleason grade of tumor focus at the margin ≥ 4 are at elevated risk for BCR. However, this study suggests that patients with pT2 tumors with positive surgical margins have a relatively low risk of biochemical recurrence and adjuvant radiation may be over treating this sub population. The subsets at greatest risk for BCR may benefit from more frequent PSA monitoring to direct salvage therapies.

Prostate cancer cell-stromal cell crosstalk via FGFR1 mediates antitumor activity of dovitinib in bone metastases.

Bone is the most common site of prostate cancer (PCa) progression to a therapy-resistant, lethal phenotype. We found that blockade of fibroblast growth factor receptors (FGFRs) with the receptor tyrosine kinase inhibitor dovitinib has clinical activity in a subset of men with castration-resistant PCa and bone metastases. Our integrated analyses suggest that FGF signaling mediates a positive feedback loop between PCa cells and bone cells and that blockade of FGFR1 in osteoblasts partially mediates the antitumor activity of dovitinib by improving bone quality and by blocking PCa cell-bone cell interaction. These findings account for clinical observations such as reductions in lesion size and intensity on bone scans, lymph node size, and tumor-specific symptoms without proportional declines in serum prostate-specific antigen concentration. Our findings suggest that targeting FGFR has therapeutic activity in advanced PCa and provide direction for the development of therapies with FGFR inhibitors.