ASCO has become a little more interesting for prostate cancer.

Today’s item is about a mega-analysis that confirms that the site of metastatic tumors will  powerfully predict overall survival (OS) among men with metastatic castration resistant prostate cancer (mCRPC).

Older and smaller studies had previously suggested that the metastatic site is prognostic for OS.  This meta-analysis pooled data from five phase 3 trials which included  3,993 chemotherapy-naïve men with mCRPC.

“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.

In all five phase 3 studies the subject men received docetaxel (chemotherapy) with or without one or more investigational agent (prednisone, bevacizumab, atrasentan, zibotentan, or estramustine).

The men were categorized as having visceral (lung, liver) or non-visceral metastasis (lymph nodes or bone metastasis, with or without nodal involvement). Men with adrenal or brain metastases represented 1% of men and were excluded from the meta-analysis.

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