In regard to therapy and prognosis of urological tumors, specific tumor markers are lacking especially in renal and urinary bladder carcinoma. Our study examines the relevance of serum serotonin levels to urinary bladder, prostate, renal, and testicular carcinoma when it comes to prognosis and occurrence of these oncological conditions.

Serotonin levels were obtained in 109 patients presenting with urothelial carcinoma to the urinary bladder, adenocarcinoma of the prostate and renal cell carcinoma, as well as presenting with seminomatous and non-seminomatous testicular tumors. All of these conditions varied in grades and metastases. Serum levels were drawn between 7 and 8 a.m. exclusively in order to avoid circadian changes.

Serotonin levels in urothelial carcinoma appeared within pathological range in correlation with tumor stage, life expectancy, and statistical significant with distant metastases. In prostate carcinoma, serotonin levels showed a tendency with organ exceeding growth, Grading/Gleason Score, PSA values >100 ng/ml, and the presence of distant metastases. In renal cell carcinoma, serotonin levels were decreased in patients with lymph node and distant metastases; there was no significant correlation with extent of infiltration. In regard to testicular carcinoma, decreased serotonin levels were merely noted in mixed tumors and the one extragonadal seminoma. Otherwise there was no correlation observed with stage and grade as well as with common tumor markers (AFP/βHCG).

Serotonin levels are suitable for prognostic evaluation of urothelial carcinoma in the urinary bladder, adenocarcinoma of the prostate, and renal cell carcinoma, especially taking into account the lab cost of 25€ per test.