Elevated level of serum carbohydrate antigen 19.9 as predictor of mortality in patients with advanced medullary thyroid cancer

BACKGROUND: Medullary thyroid cancer (MTC) is capable of secreting several proteins, such as calcitonin (Ct), carcinoembryonic antigen (CEA), chromogranin and others. Recently, we observed an aggressive MTC with high levels of serum carbohydrate antigen 19.9 (Ca 19.9) and a rapid evolution to death. OBJECTIVE: The aim of this study was to evaluate whether high levels of serum Ca 19.9 could be a prognostic factor of death in patients with advanced MTC. PATIENTS AND METHODS: We measured Ca 19.9, CEA and Ct in 100 advanced structural recurrent/persistent MTC patients and in 100 cured or biochemically affected MTC patients. Clinical and pathological data were also collected. RESULTS: Sixteen percent of the patients with advanced MTC had high levels of Ca 19.9. The group with abnormal Ca 19.9 levels had significantly higher levels of CEA and Ct compared with the group with normal values of Ca 19.9 (P<0.0001 for both Ct and CEA). At variance, all 100 patients in the MTC control group showed normal levels of Ca 19.9. Moreover, among the advanced cases, the Ca 19.9-positive group showed a higher mortality rate than the group with normal levels. A logistic regression analysis demonstrated that an elevated level of Ca 19.9 is a predictor of mortality (OR=3.78, P=0.04), independent from Ct doubling time. CONCLUSIONS: These results demonstrated that an elevated value of serum Ca 19.9 appears to be a predictive factor of poor prognosis in advanced MTC patients and identifies those cases with a higher risk of mortality in the short term.