Endocrine Abstracts

Introduction: Occurring sporadically or as part of a familial syndrome, medullary thyroid carcinoma (MTC) is insidious in onset, aggressive in behavior and invariably a challenge to the clinician and surgeon.

Objective: To define the relationship between biochemical parameters, disease progression, and treatment outcome in patients with MTC.

Patient and methods: We studied 35 patients (11 men, 24 women) aged 50.9±14.8 years, admitted to the National Institute of Endocrinology between 2004 and 2012 and diagnosed with MTC: six with MEN2A syndrome, three with familial MTC with documented RET mutation and 26 patients with sporadic MTC. Most patients presented with a thyroid lump or for screening if from a MEN2A kindred, seven with chronic diarrhea and 2-paraneoplastic Cushing syndrome.

Results: Calcitonin at diagnosis was 1586±1924 pg/ml (25 of 35 patients with available data); 36% were >2000 pg/ml, the upper limit of the assay. TNM classification at diagnosis shows 56.67% of patients in stage IV, 33.33% stage III, 3.33% stage II, and 6.67% stage I – highlighting the aggressiveness. The onset of symptoms was 22.5±29.8 months before diagnosis, delayed in two cases by false negative FNAB. Most patients underwent total thyroidectomy with (60%) or without neck dissection (11.4%), in 22.9% partial thyroidectomy was performed and in two patients (5.7%) oncologic evaluation without surgery was recommended because of wide metastatic spread; 39.4% required multiple surgeries. Calcitonin decreased to 764±2103 pg/ml at 3–6 months postop while the carcinoembrionic antigen decreased from 147.3±283.9 to 5.35±7.04 ng/ml. Only eight patients showed biochemical remission at 3–6 months postop: two patients were TNM stage I at diagnosis, six were stage III. In patients with persistent disease, adjuvant therapies were tried: chemotherapy, external radiotherapy, internal radiotherapy, somatostatin analogues, radioiodine and IFN.

Conclusion: Despite the potential for cure of MTC with timely intervention, optimal results are still achieved in a minority of cases, mostly due to the delayed diagnosis. After the ‘surgical’ window has passed, even a sustained multidisciplinary effort leads to poor results.