Prolactin and colorectal cancer: Is there a connection?

The purpose of this study was to confirm the reported incidence of hyperpro lactinemia in colorectal cancer and to find further evidence for an ectopic prolactin production by the tumor. Material and method Thirty two consecutive patients with an adenocarcinoma of the colon (n = 17) or the rectum (n = 15) were included. Preoperative se rum prolactin concentrations were determined and correlated with CEA concen trations and tumor stages. To exclude an ectopic production by the colon ca ncer, prolactin concentrations were determined during the operation, in the peripheral blood and in the efferent venous drainage area of the tumor. Af ter resection, immunohistochemical staining for prolactin was made in all r esected tumors. Results. In all except two patients with a rectal cancer, preoperative plas ma prolactin concentrations were normal. Peroperative serum concentrations of prolactin were high in all patients. No significant gradient was found b etween the peripheral venous concentration and the local venous concentrati on in the drainage area of the tumor. Immunohistochemical staining for prol actin was positive in only one rectal cancer. Finally, no correlation was f ound between plasma prolactin concentrations and tumor stages or CEA concen trations. Conclusion. Our results do not support the hypothesis of an ectopic prolact in production by colon adenocarcinoma. Only in a subgroup of rectal cancers , an ectopic prolactin production remains probable. At present, prolactin cannot be recommended as a tumor marker in colorectal cancer.