Endocrine Abstracts

Background: The recommended method of initial testing for MEN2A is either a single or multi-tiered analysis to detect RET mutations in exon 8, 10, 11, 13, 14, 15, and 16.

The aim of the study was to determine the relationship between the aggressiveness of the clinical course of MTC and identified mutations.

Materials and methods: The research is carried out of the program ‘To develop and implement effective technologies for the diagnostic detection and observation of patients with MEN2A.’ 32 patients with established medullary thyroid cancer (MTC), who underwent genetic testing, with the presence of pathogenic mutations of the RET proto-oncogene, were selected. The patients were divided into 3 groups depending on whether the mutation of the RET gene belongs to the highest, high, and medium risk levels.

Results: The number of carriers of the mutation of the highest risk level (16 exon M918T) was 2 people, which is 6.25% of the total. The median age at diagnosis is 18 years. At the time of diagnosis, the metastatic form of the disease was not detected in this group of patients. After the treatment, no recurrence of the disease was recorded in patients. In 1 of 2 patients, the presence of pheochromocytoma was established. The number of carriers of high-risk mutations was 11 people, which is 34.38%. All mutations are localized in exon 11. The average age of diagnosis is 28.7 years. At the time of diagnosis, the metastatic form of the disease was detected in 1 patient, which is 9.1%. After the treatment, remote recurrence of the disease was registered in 1 patient (9.1%), and local recurrence - in 2 patients, which is 18.2%. In 4 people (36.4%) pheochromocytoma was found. In 19 people, pathogenic mutations of the RET gene were identified, which are related to the level of moderate risk, which accounted for 59.37% of the total. Mutations in these patients are localized in exon 10 In this group of patients, MTC was diagnosed on average at the age of 41.1 years. The metastatic form of the disease at the time of diagnosis was not detected in this group. Local recurrence after the treatment was registered in 4 patients (21.05%), remote relapses in this group of patients were not registered. Pheochromocytoma was not detected in this group.

Conclusions: High-risk mutations are characterized by the earliest onset of the disease, as well as the most frequent presence of pheochromocytoma.