Neuroendocrine lung tumors represent approximately 20% of all lung tumors. They range from low-grade well-differentiated NETs and well-differentiated neuroendocrine carcinomas (typical and atypical carcinoids) to aggressive poorly differentiated small-cell and large-cell neuroendocrine carcinomas. They can develop different clinical syndromes due to ectopic hormone secretion.
We analyzed 178 patients with neuroendocrine tumors (age range: 1779 years, 51.4 mean) treated at our department in last 5 years. The diagnosis was based on histological and immunohistochemical examinations and they were classified according to the WHO classification. Neuroendocrine lung tumors occurred in 35 (19.7%) patients (age range 2479, 51.4 mean). Among those, 14 (40%) patients had well-differentiated neuroendocrine tumor, 16 (45.7%) had well-differentiated neuroendocrine carcinoma, SCLC was found in 4 (11.4%) cases, and one patient (2.8%) had mixed endocrine/adenocarcinoma of the lung. Two patients (8.6%) with well-differentiated NETs had ectopic secretion of ACTH. Four patients had clinical presentation of MEN1 syndrome while no mutations in MEN-1 gene were found. Eight patients (22.8%) had carcinoid syndrome. At the time of diagnosis in 12 (34.3%) patients distant metastases were evident: 9 with well-differentiated neuroendocrine carcinoma, 2 with SCLC, and 1 with mixed carcinoma. Primary tumor was operated in 21 (60%) patients. In 4 of them (11.4%) locally recidivant tumor occurred (occurrence range: 8120 months, mean 37.5), 2 with atypical and 2 with typical carcinoid tumors. Four patients with atypical tumors (11.4%) developed distant metastases after surgery (occurrence range: 48120 months, mean 96.0). They mostly metastasized in the liver (55.5%), bones (33.3%) and adrenal glands (33.3%). Twelve patients (34.3%) with metastatic disease died durring this period, 7 with atypical carcinoids and 3 with poorly differentiated carcinomas; 2 patients died due to non-tumor related causes.
Our data are in concordance with literature, local recurrences and distant metastases are more frequent in aggressive tumors. Tumor biology as defined by WHO classification is most relevant prognostic factor.