Endocrine Abstracts

A rare and aggressive form of thyroid malignancy, medullary thyroid carcinoma (MTC) is virtually incurable except by complete surgical resection. Due to its insidious onset and extensive spread at diagnosis, its prognosis is often poor.

Aim: To evaluate treatment outcome and prognosis in patients diagnosed with MTC admitted to our department between 2004 and 2013.

Patients and methods: We identified 21 patients (eight men and 13 women) with enough clinical and laboratory data to allow analysis. The average age at diagnosis was 39.9±16.8 years; five patients belonged to MEN2A kindreds with documented RET codon 634 mutation, two to familial MTC kindreds (codon 804 mutation), and 14 patients had sporadic MTC. Evaluation was performed at 3–6 month-intervals in the first 2–3 years after surgery, and included clinical examination, imaging and serial calcitonin (CT).

Results: The onset of symptoms was 15.4±19.9 months before diagnosis, and treatment was further delayed in two asymptomatic MEN2A patients who initially refused surgery. CT at diagnosis was <400 pg/ml in 37.5 and 31.32% were >1000 pg/ml, showing advanced disease. Total thyroidectomy with neck dissection was performed in 67% of patients; 33% required multiple surgeries and only 35% of patients had no local residual/recurrent tumor. CT levels 3–6 months postop were <15 pg/ml in 33.33% and >400 pg/ml in 16.67% – suggesting metastatic spread. In five patients CT decreased after the immediate post-surgery moment (49.3±43.3 vs 36.9±40.3 pg/ml, P= NS), suggesting that the 3–6 month interval is more appropriate for testing. Two cases exhibited metastatic disease despite normal CT with rapid progression towards death, suggesting dedifferentiation. At the end of follow-up (82±123.9 months) only 25% of patients had CT <10 pg/ml suggesting cure.

Conclusion: Despite up-to-date diagnostic algorithms and proficient surgery performed in tertiary endocrine centers, the prognostic of MTC is still poor, mostly due to a delayed diagnosis. We advocate for CT measurements in any suspicious thyroid nodule.