Endocrine Abstracts

Introduction: Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor that represents the most aggressive form of thyroid carcinoma, usually diagnosed at advanced stages. Serum calcitonin (CT) is the sensitive and specific marker of sporadic and hereditary CMT. It is a diagnostic, prognostic and follow-up marker.

Purpose of the study: To investigate the correlation between the risk of metastasis and CT levels at the time of diagnosis of MTC.

Materials and methods: Retrospective study including patients followed for MTC in the endocrinology and diabetology department of the CHU Ibn ROCHD in Casablanca from 2007 to 2022. The statistical analysis was carried out by the SPSS 25.0 software.

Results: We recruited 25 patients followed for CMT; the average age was 46.9 years, with a female predominance (72%). All patients underwent total thyroidectomy, bilateral lymph node dissection was performed in sixteen patients and unilateral in three patients. The MTC was in the context of MEN in six patients (24%), the genetic study of mutations of the RET proto-oncogene was positive in three patients. Fifteen of the cases presented a metastatic form (60%), the lymph node localization of which was present in all patients and at a distance in ten patients (66.7%). The CT level at the time of diagnosis in patients with a metastatic form was > 500 pg/ml (mean value 3855.6 pg/ml) in 66.6% of patients (P<0.01), while the CT level was < 100 pg/ml in patients without metastases. Most had undergone a first incomplete thyroid surgery. Moreover, the tumors were larger, multifocal (P<0.05) and with capsular invasion (P<0.02). Among these patients, three benefited from chemotherapy sessions, radiotherapy was performed in two patients, one patient was put on targeted therapy with vandetanib and two patients are scheduled for treatment with sorafenib.

Conclusion: CT is a very sensitive biochemical marker. The absence of its preoperative assay leads to a delayed diagnosis of MTC and the initial surgery is often incomplete. Indeed, preoperative CT levels are strongly correlated with disease progression, which requires adequate management with close monitoring of the disease.