Aim: To evaluate the significance of plasma free serotonin (5-hydroxytryptamine) and Ca15.3 for the early detection of breast cancer recurrence.
Materials and methods: Free serotonin and Ca15.3 levels were measured by I-125-Serotonin RIA (DDV Diagnostica, Marburg, Germany) in plasma and an ELISA kit (Roche Diagnostic GmbH, Mannheim, Germany) in serum, respectively in women (N=29) who responded to primary treatment for breast cancer and who were followed-up for recurrence. For analysis, patients were sub-divided according to TNM staging into groups with localized (T1-2N0-M0) and advanced (T1-2N1-2M0-1) disease. The control group were healthy blood donors.
Results: Patients with advanced disease had a significantly higher plasma serotonin level than those with localized disease or controls, whereas Ca15.3 levels remained in normal range in all groups. At the time of serotonin measurement, radiological findings were negative for all patients in the localized-disease group, but positive in nine patients in the advanced-disease group.
Conclusion: Plasma free serotonin may be used for the early detection of recurrent/metastatic breast cancer disease, but validation on a larger number of patients is needed.
Keywords: Ca15.3; Plasma free serotonin; biomarker; breast cancer; recurrence.