How to interpret serum CA 125 levels in patients with serosal involvement? A clinical dilemma

The clinical utility of tumor markers is limited due to their low specificity. CA 125, an ovarian tumor marker, is a sensitive but nonspecific tumor marker used especially in the follow-up of ovarian cancer for monitoring the efficacy of therapy and for early detection of recurrence. The use of the CA 125 serum assay as a single diagnostic tool is restricted by the fact that the antigen to CA 125 is also produced by normal epithelia (peritoneum, pleura, and pericardium). Since an elevated serum CA 125 level is a marker of ovarian cancer, a laparotomy is the final tool of the physician to clarify the etiology. However, unnecessary operations have been reported in the literature revealing no ovarian pathology (e.g. cirrhosis, tuberculous peritonitis or pancreatic cancer) in such patients. Elevated serum CA 125 levels require a cautious operative planning in patients without a notable tumor mass. A secondary interpretation is needed in case of elevated CA 125 levels whenever serosal (peritoneal, pleural, or pericardial) fluid is present.