Endocrine Abstracts

Introduction: Medullary thyroid cancer arises from the calcitonin-secreting parafollicular C cells and consists of a spectrum of disease that ranges from extremely indolent tumours, where patients may survive for many years with a large tumor burden, to aggressive types associated with a high mortality rate. The objective of our study is to evaluate the prognostic factors and outcomes of patients diagnosed with medullary thyroid cancer in a homogenous population, and to examine the tissue sample of patients diagnosed with MTC for mutations in the RET proto-oncogene from the same period.

Methods and design: A retrospective analysis of the National Cancer Registry in Ireland was undertaken, for patients with a diagnosis of medullary thyroid cancer between 1998 and 2007. The Kaplan–Meier method was used to determine overall survival and factors predictive of outcome were determined by univariate and multivariate analysis by Cox regression using STATA 13 Software.

Results: Forty-six patients were diagnosed with MTC, 55.8% were females and 44.2% were males. A median age of 52was found. The overall median survival was 6.32 years and the 1- and 5-year overall survival was 88.37 and 62.79% respectively, with a 10-year survival calculated at 48.63%. On univariate analysis age, stage and surgical intervention were statistically significant indicators of prognosis. T stage and age remained statistically significant indicators of prognosis on multivariate analysis. Two patients with no history of MEN syndromes or family history of MTC had RET proto-onocogene mutations.

Conclusions: Our patient cohort was substantially older than what is commonly seen in the literature. There was a very low pick up of RET mutations in sporadic MTC in our patient cohort, and along with relatively poor outcomes, this suggest that further studies of this population may allow us to identify aggressive variants of medullary thyroid cancer.