title: Serum calcitonin levels with calcium loading tests before and after total thyroidectomy in patients with thyroid diseases other than medullary thyroid carcinoma.
abstract: Calcitonin is a very sensitive tumor marker of medullary thyroid carcinoma (MTC). Patients with MTC have usually very high levels of serum calcitonin that can be used to diagnose the disease. In order to improve diagnostic sensitivity in family members with small MTCs or to evaluate postoperative biochemical cure status, measurement of calcitonin stimulated with combined intravenous calcium gluconate and pentagastrin has been widely adopted; however, gastrin has become unavailable. Currently, a provocative test using only calcium gluconate is performed; however, the standard values for this test have not been reported. We therefore conducted calcium gluconate stimulation tests in 20 patients before and after total thyroidectomy for thyroid diseases other than MTC. Preoperatively, the mean basal calcitonin level was 24.1 pg/mL and increased to 46.9pg/mL after calcium infusion. The ratio of the peak calcitonin level to the basal value ranged from 1- to 5.23-fold, with a mean of 1.94. The ratio was higher than 3-fold in 3 patients. In 2 patients, peak calcitonin levels exceeded 100 pg/mL. Postoperatively, the mean basal level slightly decreased to 21.15pg/mL and the response to calcium stimulation markedly decreased, with the mean ratio decreasing to 1.1-fold (range, 0.86- to 1.73-fold, maximum peak level, 33 pg/mL). Thus, some subjects without MTC show response to the calcium stimulation test up to 5.24 times the ratio and a peak value of 160 pg/mL, suggesting the requirement for judicious judgment for the early diagnosis of MTC in family members; however, after total thyroidectomy, none of the subjects showed an increase of more than 2-fold or a peak value of 33pg/mL, suggesting that responses greater than 2-fold after MTC surgery might be abnormal, indicating the presence of residual tumor.
authors.affiliation: Kuma Hospital, Kobe, Japan. kudo@kuma-h.or.jp
authors.forename: Takumi
authors.initials: T
authors.lastname: Kudo
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Tomonori
authors.initials: T
authors.lastname: Yabuta
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.forename: Takuya
authors.initials: T
authors.lastname: Higashiyama
authors.forename: Chisato
authors.initials: C
authors.lastname: Tomoda
authors.forename: Mitsuhide
authors.initials: M
authors.lastname: Hirokawa
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Amino
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood; D002116:Calcitonin / Q000097:blood*; D002125:Calcium Gluconate / Q000494:pharmacology*; D018276:Carcinoma, Medullary / Q000097:blood / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual; D013959:Thyroid Diseases / Q000097:blood* / Q000601:surgery*; D013961:Thyroid Gland / Q000601:surgery; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis; D013965:Thyroidectomy
chemical_list: D014408:Biomarkers, Tumor; D002116:Calcitonin; D002125:Calcium Gluconate