[Serum testosterone: a possible marker for colorectal cancer].

A reduction of circulating testosterone has been reported in lung, stomach and pancreatic carcinoma. In order to evaluate the concentration of this hormone in patients with colorectal cancer, we studied 58 men with histologically confirmed disease. Seric testosterone, estradiol and carcinoembryogenic antigen were simultaneously measured in 24 patients under pre-surgical evaluation (group I) and in 34 patients after surgical resection (group II). The results were compared with a control group carrying benign gastrointestinal pathologies. According to the Kruskal-Wallis test, the testosterone level in cancer groups was significantly lower than in the control group (p < 0.0001). We have also observed a statistical significance between subgroups I and II compared to the control group (p < 0.001), while no conspicuous differences were perceived in estradiol concentrations between benign and cancer groups. Decreased serum levels of testosterone were found in 69% of patients with colon or rectal carcinoma and 56.9% of them had raised levels of carcinoembryonic antigen. The combined determination of both biomarkers increase to 86.2% the sensitivity of tumor screening compared with a single detection. Our results suggest that the combination of testosterone and carcinoembryonic antigen enhances the efficiency of tumor screening. We conclude that the evaluation of circulating testosterone could be a new and more sensitive assay for diagnosis and follow-up of colorectal carcinoma in males, specially in patients with normal levels of carcinoembryonic antigen.