Metastatic tumor sites predict OS in castration resistant prostate cancer

CHICAGO, IL—The site of metastatic tumors powerfully predicts overall survival (OS) among men with metastatic castration resistant prostate cancer (mCRPC), confirms a meta-analysis presented at the 2014 American Society of Clinical Oncology (ASCO) Annual Meeting.

Although smaller studies had previously suggested that metastatic site is prognostic for OS, the new meta-analysis pooled data from five phase 3 trials, representing 3,993 chemotherapy-naïve patients with mCRPC. The authors identified another four similar trials, from which they are still collecting data.

“These data confirm that patients with mCRPC with lung and liver metastasis treated with docetaxel represent intermediate and poor prognostic subgroups, respectively,” reported lead study author Susan Halabi, PhD, and coauthors from the Duke University Medical Center in Durham, NC. “As anticipated, [patients with] CRPC with liver metastases had the worst OS (12.1 months).”

“While patients with lung mets had better OS (17 months) compared to [patients with] liver metastasis (12 months; P < 0.001), they had significantly worse survival than patients with non-visceral bone metastasis (20 months; P < 0.001),” she added.

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Patients in all five phase 3 studies received docetaxel with or without one or more investigational agent (prednisone, bevacizumab, atrasentan, zibotentan, or estramustine).

Patients were categorized as having visceral (lung, liver) or nonvisceral metastasis (lymph nodes or bone metastasis, with or without nodal involvement). Patients with adrenal or brain metastases represented 1% of patients and were excluded from the meta-analysis, Dr. Halabi said.

Pooled hazard ratios for lung metastasis compared with liver metastasis was 1.4 (95% CI: 1.2-1.7; P < 0.001).

Median OS was 27 months (range, 25-32 months; n = 187 [5%]) for lymph node-only metastasis; 20 months (range, 19-21 months) for bone metastasis with or without lymph node involvement; 16.5 months for lung metastasis with or without bone metastasis (14.8-18.4 months); and 12 months for liver metastasis (10-14 months).

“Sites of metastasis are independent and significant correlates of overall survival,” Dr. Halabi concluded. “These data may help in treatment decisions and in the design of future clinical trials in [patients with] mCRPC.”

Reference

1. Halabi S, Kelly WK, Zhou H et al. Abstract 5002. Presented at: 2014 American Society of Clinical Oncology (ASCO) Annual Meeting; May 30-June 3, 2014; Chicago, IL.

This article originally appeared on Cancer Therapy Advisor