Medullary thyroid carcinoma in Northern Ireland, 1967-1997.

Background: The experience of managing medullary thyroid carcinoma (MTC) in a specialist endocrine surgery unit was reviewed. Methods: The case records of 38 patients (19 male, 19 female) treated over a 30 year period were studied. Results: There were 23 (60.5%) patients with sporadic MTC while the remainder had familial MTC - 12 multiple endocrine neoplasia (MEN) type 2A, two MEN type 2B, one non-MEN familial medullary thyroid carcinoma (FMTC). Sporadic MTC patients were significantly older at presentation (median 56 years, interquartile range 41.5-61.3 years) compared to MEN 2A patients (median 26 years interquartile range 17.5-34 years) and had more advanced stage of disease. Survival of MTC patients was significantly worse in sporadic disease than in those with MEN 2A (P < 0.0001). All familial cases had bilateral multifocal tumour whereas in sporadic patients only unilateral disease was seen. The availability of genetic testing now allows early identification of affected members of familial MTC kindreds. This has led to total thyroidectomy being performed on the basis of positive genetic screening alone in three patients (two MEN 2A, one FMTC), in all of whom widespread C-cell hyperplasia and microscopic multifocal invasive MTC were identified histologically. Conclusions: The management of MTC has changed during the study period with total thyroidectomy recommended as the primary procedure of choice for all patients. In the familial setting, positive genetic testing now allows thyroidectomy to be performed at an early pre-clinical stage, with the hope of permanent cure.