External Validation of a Prognostic Score for Survival in Lung Carcinoids

SIMPLE SUMMARY: Incidence of lung carcinoids is rapidly increasing, but the correct management of these patients is still debated. Although their clinical behaviour differs from Non-Small Cell Lung Cancer, the same staging system is used for these tumors, even if it presents limitations in prognosis prediction and overlapping curves especially regarding sub-stages. For these reasons, in recent years, ad hoc scores have been constructed aiming to better stratify prognosis and indicate appropriate treatment options. In particular, a score including the node ration as nodal factor was proposed, although external validation was not possible. The aim of this study is to validate this score, for the possibility of identifying a specific class of patients that may benefit from specific follow-up schedules or post-operative treatments. ABSTRACT: Background: A prognostic score including T-dimension, age, histology and lymph node ratio was previously proposed in absence of an external validation dataset. The aim of the current study was to validate the proposed prognostic score using an independent dataset. Methods: Data of patients with lung carcinoids, who underwent surgical resection and lymphadenectomy in five institutions from 1 January 2005 to 31 December 2019, were retrospectively analyzed. Two risk groups were created based on the following data: age, histology, node ratio and pT for disease-free survival (DFS); age, sex, node ratio and pT for overall survival (OS). The previously proposed score was validated, identifying two groups of patients: a high risk (HRG) and low risk (LRG) group. Results: The final analysis was conducted on 283 patients. Regarding DFS, 230 (81.3%) patients were assigned to the LRG and 53 (18.7%) to the HRG. Considering OS, 268 (94.7%) were allocated in the LRG and 15 (5.3%) in the HRG. The 5-year DFS was 92.7% in the LRG vs. 67% in the HRG (p < 0.001) while the 5-year OS was 93.6% in the LRG vs. 86.2% in the HRG (p = 0.29) with clear curve separation. Conclusion: Our analysis confirmed the validity of the composite score for DFS in lung carcinoids. Regarding OS, statistical significance was not reached because of a low number of deaths and patients in the HRG.