An uncommon, but very aggressive form of prostate cancer is known as Neuroendocrine prostate cancer (NEPC). It is generally accepted that Circulating Tumor Cell (CTC) counts as measured by CellSearch (a method to catch and count these cells in the blood) are prognostic for most men with metastatic prostate cancer (mPC), but are not well understood in NEPC.

A group of researchers retrospectively identified men with metastatic PC and available CTC enumeration (CellSearch methodology) and compared counts/7.5 mL blood and overall survival (OS), measured from the first recorded CTC count until death or last follow up.

Entry criteria for clinical trials were used to define which men had NEPC, including histology (small cell/neuroendocrine carcinoma or adenocarcinoma with more than 50% NE staining), serum chromogranin greater than 5x ULN and/or neuron specific enolase greater than 2x ULN, and/or predominant liver/