The aims of the study were to identify
medullary thyroid cancer (MTC) in its earliest stages by screening patients with basal
calcitonin measurements and to determine whether basal serum
calcitonin measurements should be a part of the routine evaluation of a
nodular goiter. Basal serum
calcitonin levels 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. Their 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 between 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 diagnosed as MTC as a result of family screening. Basal serum
calcitonin levels were higher than 150 pg/mL in these patients. Fine needle aspiration biopsy (FNAB) of 2 of 4 MTC patients were incorrectly diagnosed as
papillary carcinoma; 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 of basal
calcitonin levels in patients with malignant or suspicious FNAB may be a cost-effective approach to screen for MTC. High basal serum
calcitonin levels increase the chance of curative
therapy by diagnosing MTC in the early stages. It is superior to FNAB for diagnosis of MTC.