doiSerbia

Medullary thyroid carcinoma: Genetic screening and prophylactic thyroidectomies

Bergant Damijan M. (Institute of Onkology, Ljubljana)
Hočevar Marko (Institute of Onkology, Ljubljana)

Medullary thyroid carcinoma (MTC) occurs sporadically or is inherited as a characteristic component of MEN 2A, MEN 2B and familial MTC. Germ/line point mutations in RET proto/onkogene are responsible for tumor arise and inheritance. Genetic screening provides information of these RET mutations in family members even before pathologic changes of C-cells progress to MTC. The aim of our study was to identify carriers of RET gene mutations in our patients with MTC and their kindred. Surgical therapy was based on genetic testing results and clinical features. Prophylactic thyroid surgery was the subject of interest. From 1969-2002 105 patients with MTC (88 families), were treated and/or diagnosed at the institute of Oncology Ljubljana, Slovenia. Genetic testing was so performed in 58/88 MTC index patients (24 males (16 - 93y) and 34 females (23 -77y)) and their 50 kindred, aged 8 - 67y. Twentyfive/50 kindred were from affected families. Germline mutations of RET proto-onkogene were found in 12/58 (20, 6%) MTC index patients - 2 males (16 and 65 y) and 10 females (23-55y, median 36y) and in 14/25 kindred from 12 affected families - 5 males aged 18-57 years (median 21) and 9 females aged 12-54 years (median 41) but were absent in 11/25 kindred. Genetic screening results indicate thyroid surgery in all 14 kindred; also MTC was clinically suspected or diagnosed in 11/14 patients and 3/14 were candidates for prophylactic thyroidectomy. Total thyroidectomy with central neck dissection was the minimal surgical procedure. Prophylactic thyroidectomy based on genetic testing results allows earlier diagnosis and treatment of patients, even before pathologic changes of C-cells occur. Patient’s age and codon mutation influence the timing of surgery and even it’s extend.

Keywords: medullary thiroid carcinoma, genetic