Importance of gender-specific calcitonin thresholds in screening for occult sporadic medullary thyroid cancer.
Men and women differ in thyroidal C-cell mass and calcitonin secretion. This difference may have implications for the definition of calcitonin thresholds to distinguish sporadic C-cell hyperplasia from occult medullary thyroid cancer. This retrospective study examined the hypothesis that gender-specific calcitonin thresholds predict occult medullary thyroid cancer more accurately among patients with increased basal calcitonin levels than unisex thresholds. A total of 100 consecutive patients were evaluated with occult sporadic C-cell disease no larger than 10 mm who were referred for increased basal calcitonin levels and underwent pentagastrin stimulation preoperatively at this institution. Altogether, gender-specific calcitonin thresholds predicted medullary thyroid cancer better than unisex thresholds. At lower (<or=50 pg/ml basally; <or=500 pg/ml after stimulation), but not higher, calcitonin serum levels, women revealed medullary thyroid cancer four to eight times more often than men. Most discriminatory between C-cell hyperplasia and medullary thyroid cancer was a basal calcitonin threshold of 15 pg/ml (corrected 20 pg/ml) for women and 80 pg/ml (corrected 100 pg/ml) for men, based on the greatest accuracy at the lowest possible calcitonin level. The respective gender-specific stimulated peak calcitonin thresholds were 80 pg/ml (corrected 100 pg/ml) and 500 pg/ml. Corresponding positive predictive values for medullary thyroid cancer at these calcitonin thresholds were 89 and 90% for women, as opposed to 100% for men. To increase the positive predictive value for women to 100%, the respective calcitonin thresholds would have to be raised to 40 pg/ml (corrected 50 pg/ml) and 250 pg/ml. These findings indicate that gender-specific calcitonin thresholds predict sporadic occult medullary thyroid cancer better than unisex thresholds.
Machens
Andreas
A
Department of General, Visceral and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany. andreasmachens@aol.com
Hoffmann
Florian
F
Sekulla
Carsten
C
Dralle
Henning
H
D002116:Calcitonin / Q000097:blood*; D018276:Carcinoma, Medullary / Q000097:blood* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006965:Hyperplasia / Q000175:diagnosis*; D008197:Lymph Node Excision; D008297:Male; D008875:Middle Aged; D010418:Pentagastrin; D012189:Retrospective Studies; D012737:Sex Factors; D013961:Thyroid Gland; D013964:Thyroid Neoplasms / Q000097:blood* / Q000473:pathology; D013965:Thyroidectomy
D002116:Calcitonin; D010418:Pentagastrin