Evaluation of routine basal serum calcitonin measurement for early diagnosis of medullary thyroid carcinoma in seven hundred seventy-three patients with nodular goiter

The aims of the study were to identify medullary thyroid cancer (MTC) in it s earliest stages by screening patients with basal calcitonin measurements and to determine whether basal serum calcitonin measurements should be a pa rt of the routine evaluation of a nodular goiter. Basal serum calcitonin le vels were obtained from 75 patients (female:male 57:18, mean age 42.8 years , range with 18-76 years) with nonnodular thyroid disease as controls. Thei r mean basal calcitonin level was 7,8 +/- 0.4 pg/mL with a range of 5-27 pg /mL. Seven hundred seventy-three patients with nodular goiter were included in the study (female:male 586:187) with the mean age of 46.1 years (range 17-78). Four patients had elevated basal serum calcitonin levels ranging be tween 150-1000 pg/mL. These 4 patients underwent surgery. MTC was confirmed by histopathology in all 4. One patient's mother and brother were also dia gnosed as MTC as a result of family screening. Basal serum calcitonin level s were higher than 150 pg/mL in these patients. Fine needle aspiration biop sy (FNAB) of 2 of 4 MTC patients were incorrectly diagnosed as papillary ca rcinoma; another had malignant cytology and the fourth had benign cytology. None were diagnosed as MTC on the basis of FNAB. In conclusion, calcitonin measurement is an effective method for the diagnosis of MTC. Measurement o f basal calcitonin levels in patients with malignant or suspicious FNAB may be a cost-effective approach to screen for MTC. High basal serum calcitoni n levels increase the chance of curative therapy by diagnosing MTC in the e arly stages. It is superior to FNAB for diagnosis of MTC.