Prognostic factors of recurrence and disease-free survival in radically resected pulmonary carcinoids: a real-world analysis

Background: Pulmonary carcinoids (PCs) are rare neuroendocrine lung tumors which may recur, thus worsening their otherwise favorable overall prognosis. Aiming to identify patients at risk for recurrence, we examined parameters affecting disease-free survival (DFS). Methods: A retrospective single-center analysis of 82 consecutive patients undergoing curative intent resection for primary PC tumors between 2010 and 2019 was carried out. Kaplan-Meier method was utilized for survival analysis. Independent prognostic factors were determined using multivariable Cox and logistic regression. Results: During the observation period 82 patients, 48 females (58.5%) and 34 males (41.5%) were operated, representing 84 cases of PCs, 56 typical (TCs) (66.7%) and 28 atypical (ACs) (33.3%) carcinoids. Five-year overall survival was 87.5% and 84.7%, 5-year DFS 97.5% and 74.9% (P=0.012) for TCs and ACs, respectively. Recurrences occurred in one patient (1.8%) with TCs and five patients (17.9%) with ACs (P=0.014). Using multivariable Cox regression, tumor size (cm) remained as an independent prognostic factor for reduced DFS (P=0.018). In logistic regression, nodal involvement (P=0.043) and tumor size (cm) (P=0.023) were independently associated with higher risk of recurrence. Age, sex, smoking, location, and Ki-67 index were not independently associated with recurrence or DFS. Conclusions: Recurrence in PCs after complete resection is relatively rare. However, DFS is reduced in ACs compared to TCs. Tumor size (cm) and nodal involvement appear as the most important prognostic factors associated with recurrence in PCs, independent of histologic type.