New Prognostic Frontiers for Lung Neuroendocrine Tumors

Purpose Well-differentiated lung neuroendocrine tumors (Lu-NET) are classified as typical (TC) and atypical (AC) carcinoids, based on mitotic counts and necrosis. However, prognostic factors, other than tumor node metastasis (TNM) stage and the histopathological diagnosis, are still lacking. The current study is aimed to identify potential prognostic factors to better stratify lung NET, thus, improving patients’ treatment strategy and follow-up. Methods A multicentric retrospective study, including 300 Lung NET, all surgically removed, from Italian and Spanish Institutions. Results Median age 61 years (13-86), 37.7% were males, 25.0% were AC, 42.0% were located in the lung left parenchyma, 80.3% presented a TNM stage I-II. Mitotic count was ≥2 per 10 high power field (HPF) in 24.7%, necrosis in 13.0%. Median overall survival (OS) was 46.1 months (0.6-323), median progression free survival (PFS) was 36.0 months (0.3-323). Female sex correlated with a more indolent disease (T1; N0; lower Ki67; lower mitotic count and the absence of necrosis). Left-sided primary tumors were associated with higher mitotic count and necrosis. At Cox multivariate regression model, age, left-sided tumors and nodal (N) positive status resulted independent negative prognostic factors for OS and PFS. Conclusions This study confirms the prognostic relevance of TNM stage and diagnosis to stratify LuNET. However, the current analysis suggests a wider spectrum of clinical and pathological prognostic factors, including age and primary tumor’s location. These parameters could help clinicians to personalize the management of Lu-NET.