Medullary Thyroid Cancer: Epidemiology and Characteristics According to Data From the Marne-Ardennes Register 1975-2018.

Context: Medullary thyroid cancer (MTC) is a rare disease.

Objective: The main objective of our study was to analyze the incidence evolution of MTC with a follow-up of more than 40 years. Further, a descriptive and survival analysis was performed according to the Kaplan-Meier analysis.

Design setting and patients: This is a retrospective epidemiological study using data from the Marne-Ardennes registry from 1975 to 2018. Two hundred sixty patients with MTC were included.

Main outcome measures: The incidence was calculated in the territory of the register (Marne and Ardennes departments of France) and standardized on the demographic structure of France. Patient and tumor characteristics were described. An analysis in a subgroup comparing hereditary and sporadic forms was performed. An analysis of survival was performed.

Results: The standardized incidence shows an increasing trend over time. The incidence increased significantly from 0.41 to 0.57/100 000 person-years between 1986 and 1996 and 2008 and 2018. The MTC was hereditary in 21.2% of cases. The sex ratio (males:females) was 0.73. The average age at diagnosis was 53 years. Ninety-seven patients (37.3%) were N1, 26 (10%) were M1, and 56 (21.5%) developed metastases during the follow-up. Complete remission was obtained in 58.5% of patients. The disease was refractory for 18.1% of patients. The 5-year survival rate was 88.4%. Sporadic cases had a poorer prognosis than hereditary MTC.

Conclusion: Our study demonstrates a moderate increase in the incidence of MTC between 1975 and 2018. The prognosis remains worse for sporadic MTC than for hereditary MTC.