Changes in risk factors and Tumor Node Metastasis stage of sporadic medullary thyroid carcinoma over 41 years, before and after the routine measurements of serum calcitonin

Abstract

The measurement of serum calcitonin (CT) in all thyroid nodules for the detection of medullary thyroid carcinoma (MTC) is controversial. We compare several prognostic factors, Tumor Node Metastasis (TNM) stage, and survival in sporadic MTC patients operated on before and after the use of routine measurements of serum CT in combination with thyroid ultrasonography (US). Thirty-seven patients had been operated on between 1969 and 1989 (group I), before the use of routine measurements of serum CT and the routine use of thyroid US, and 39 (group II) had been operated on between 1990 and 2009, after the introduction of routine use of serum CT and thyroid US. There were no between-group differences concerning age and sex. Group I had larger tumors at the time of operation (P < .001) and higher postoperative serum CT levels (P < .001). Cervical lymph node and distant metastases were found more frequently in group I in comparison with group II. The cases with TNM stage I were significantly higher in group II than in group I, in contrast with the cases with TNM stage IV that were significantly higher in group I. Univariate analysis revealed a significantly higher 15-year survival rate in group II than in group I (P = .002). The postoperative CT levels were positively correlated with tumor size (P < .001). During the last 2 decades, the diagnosis of sporadic MTC at an earlier stage has been made possible by the routine use of serum CT in combination with thyroid US. The significant increase of the 15-year survival rate shows better outcome in these patients.