Natural course and survival of neuroendocrine tumors of thymus and lung in MEN1 patients

The natural course and survival of neuroendocrine tumors (NETs) of thymus (Th) and lung in multiple endocrine neoplasia type 1 (MEN1) patients are still unknown. Our objective was to assess prevalence, tumor growth, and survival of Th and lung NETs in an unselected MEN1 population with long-term follow-up. This was an observational study. A longitudinal study was performed using the Dutch national MEN1 database, including >90% of the Dutch MEN1 population >16 years of age. Patients under care of the Dutch University Medical Centers (1990-2011) (n = 323) were included. The prevalence and survival of Th and lung NETs were assessed. Linear mixed-models analysis was applied to assess tumor growth with age as a possible confounder and gender, genotype and baseline tumor size as possible effect modifiers. Th NETs occurred in 3.4% of patients, almost exclusively in males with a 10-year survival of 25% (95% confidence interval = 8%-80%). A thoracic computed tomography scan was available in 188 patients (58.2%). A lung NET was identified in 42 patients (13.0%) with a 10-year survival of 71.1% (95% confidence interval = 51%-100%). Tumor volume of lung NETs increased 17% per year (P < .001) (tumor doubling time 4.5 years). Tumor doubling time in males was 2.5 vs 5.5 years in females (P = .05). Lung NET growth was not associated with genotype or with baseline tumor size (