Medullary Thyroid Cancer in Patients Older than 45—Epidemiologic Trends and Predictors of Survival

SIMPLE SUMMARY: Sporadic medullary thyroid cancer can occur anytime in life although they tend to present at a later age (≥45 years old) when the tumors are more easily discernible or become symptomatic. We present, in this study, a group of patients diagnosed with medullary thyroid cancer at or after 45 years of age when they are more likely to develop sporadic forms of medullary thyroid cancer with regard to their natural history and prognosis. In this study, we evaluated factors affecting survival in such patients. We found that the incidence of medullary thyroid cancer in patients ≥45 years of age is increasing. Our findings suggest that patients should be offered surgical resection at an early stage to improve their outcomes. ABSTRACT: Sporadic medullary thyroid cancer (MTC) can occur anytime in life although they tend to present at a later age (≥45 years old) when the tumors are more easily discernible or become symptomatic. We aimed to identify the factors affecting the survival in patients ≥45 years of age diagnosed with MTC. We analyzed the Surveillance, Epidemiology, and End Results (SEER) registry from 1973–2016 focusing on patients ≥45 years of age with MTC as an isolated primary. A total of 2533 patients aged ≥45 years with MTC were identified. There has been a statistically significant increase of 1.19% per year in the incidence of MTC for this group of patients. The disease was more common in females and the Caucasian population. Most patients had localized disease on presentation (47.6%). Increasing age and advanced stage of presentation were associated with worse survival with HR 1.05 (p < 0.001) and HR 3.68 (p < 0.001), respectively. Female sex and surgical resection were associated with improved survival with HR 0.74 (p < 0.001) and 0.36 (p < 0.001), respectively. In conclusion, the incidence of MTC in patients ≥45 years of age is increasing. Patients should be offered surgical resection at an early stage to improve their outcomes.