Plasma serotonin level is a predictor for recurrence and poor prognosis in colorectal cancer patients.

AIM: To investigate the prognostic value of plasma serotonin levels in colorectal cancer (CRC).

PATIENTS AND METHODS: Preoperative plasma serotonin levels of 150 healthy control (HC) cases, 150 benign colorectal polyp (BCP) cases, and 176 CRC cases were determined using radioimmunoassay assay. Serotonin levels were compared between HC, BCP, and CRC cases, and those in CRC patients were related to 5-year outcome.

RESULTS: Plasma serotonin levels were markedly higher in CRC patients than in either HCs or BCP cases. An elevated serotonin level was significantly associated with advanced tumor node metastasis. Receiver operating characteristic curve analysis showed that the level of serotonin had a high predictive value for disease recurrence and mortality. Multivariate analysis revealed that high serotonin level was significantly associated with poor recurrence-free survival and overall survival.

CONCLUSION: Our results suggest that a high peri-operative plasma serotonin level is useful as a prognostic biomarker for CRC recurrence and poor survival.