Prognostic nomogram and epidemiological analysis for lung atypical carcinoid: A SEER database and external validation study

Purpose: Our study aims to delineate the epidemiological distribution of pulmonary carcinoids, including atypical carcinoid (AC) and typical carcinoid (TC), identify independent prognostic factors, develop an integrative nomogram and examine the effects of various surgical modalities on atypical carcinoid-specific survival (ACSS).Methods: Joinpoint regression model and age-group distribution diagram were applied to determine the epidemiological trend of the pulmonary carcinoids. Univariate and least absolute shrinkage and selection operator (LASSO)-based Cox regression models were used to identify independent factors, and a nomogram and web-based predictor were developed to evaluate prognosis of AC patients individually. We performed Kaplan-Meier survival analyses to compare the scope of various surgical interventions, with and without G-computation adjustment, utilising restricted mean survival time (RMST) to assess survival disparities.Results: A total of 1132 patients were recruited from the Surveillance, Epidemiology, and End Results database (SEER) and a separate medical centre in China. The mean age of AC patients was 63.4 years and a smoking history was identified in 79.8% of AC patients. Joinpoint analysis shows rising annual rates of new AC and carcinoid cases among lung cancers. Both the proportion of pulmonary TC and AC within the total lung cancer population exhibits an L-shaped trend across successive age groups. The nomogram predicted 1, 3 and 5 years of AC with excellent accuracy and discrimination. Kaplan-Meier survival analyses, conducted both pre- and post-adjustment, demonstrated that sublobar resection's survival outcomes were not inferior to those of lobectomy in patients with stage I-II and stage III disease.Conclusion: This study is the first to reveal epidemiological trends in pulmonary carcinoids over the past decade and across various age cohorts. For patients with early-stage AC, sublobar resection may be a viable surgical recommendation. The established nomogram and web-based calculator demonstrated decent accuracy and practicality.