Neuroendocrine Neoplasms of the Lung: A Prognostic Spectrum

TLDR

Neuroendocrine lung tumors comprise typical carcinoid, atypical carcinoid, large‑cell NE carcinoma, and small‑cell lung carcinoma, yet their clinicopathologic profiles and relative malignancy grades were previously undefined, prompting a multicenter collection of 383 surgically resected cases. A consensus panel of six expert pathologists applied WHO criteria to classify the tumors and analyzed their clinicopathologic relationships, excluding 18 inadequate specimens from the 383‑case cohort. Among 366 resected NE tumors, 5‑year survival varied markedly by histology—96.2% for TC, 77.8% for AC, 40.3% for LCNEC, and 35.7% for SCLC—with histologic type, resection completeness, symptoms, nodal status, and age emerging as independent prognostic factors and high‑grade histology uniformly predicting poor outcome.

Abstract

Neuroendocrine (NE) tumors of the lung include typical carcinoid (TC), atypical carcinoid (AC), large-cell NE carcinoma (LCNEC), and small-cell lung carcinoma (SCLC). Their clinicopathologic profiles and relative grade of malignancy have not been defined.From 10 Japanese institutes, 383 surgically resected pulmonary NE tumors were collected. The histologic diagnosis was determined by the consensus of a pathology panel consisting of six expert pathologists as TC, AC, LCNEC, or SCLC on the basis of the WHO classification, and its relationship to clinicopathologic profiles was analyzed.Of the 383 tumors, 18 were excluded because of an improper specimen. The pathology panel reviewed the remaining 366 tumors, and a diagnosis of NE tumor was made in 318 patients (87.4%); 55 patients had TC, nine had AC, 141 had LCNEC, and 113 had SCLC. The 5-year survival rates of patients with all stages were as follows: 96.2% for TC, 77.8% for AC, 40.3% for LCNEC, and 35.7% for SCLC. There was significant prognostic difference between TC and AC as well as between AC and LCNEC+SCLC. However, there was no difference between LCNEC and SCLC, and their survival curves were superimposed. The multivariate analysis indicated that histologic type, completeness of resection, symptoms, nodal involvement, and age were significantly prognostic.The grade of malignancy of NE tumors was upgraded in the following order: TC, AC, LCNEC, and SCLC. No prognostic difference was noted between LCNEC and SCLC. The high-grade NE histology uniformly indicated poor prognosis regardless of its histologic type.