Low Grade Neuroendocrine Tumors of the Lung

Abstract

The lung is the second most common site of neuroendocrine tumors (NETs). Typical and atypical carcinoids are low-grade NETs of the lung. They present a favorable prognosis comported to the more common high-grade NETs. The low- and high-grade NETs require different treatment strategies; effective management of these tumors is essential to prolong survival and to manage the symptoms in patients with secretory or functional tumors. These rare tumors have received little attention and education is needed for treating physicians. This mini-review will concentrate mainly on advanced low-grade lung NETs. The article describes the classification of lung NETs and the diagnostic work-up. Different treatment methods including somatostatin analogs, peptide receptor radioligand therapy, and biologic systemic therapy are discussed. Promising results from recent trials are presented and discussed in the context of the lung primary site.

Keywords: Atypical carcinoid; Carcinoid; everolimus; lung; neuroendocrine tumors; octeotride.

Figure 1

Photomicrographs of typical and atypical pulmonary carcinoid tumors. (A) Low power photomicrograph of a typical pulmonary tumor. (B) Low power photomicrograph of an atypical pulmonary carcinoid tumor with central necrosis. Reproduced with permission from: Tazelaar HD. Pathology of lung malignancies. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on November 2, 2016.) Copyright © 2016 UpToDate, Inc. For more information visit www.uptodate.com.

Figure 2

Progression-free survival curve from Radiant 4 trial. PFS curve from the RADIANT 4 trial. Reprinted from Yao et al. (36), Copyright 2016, with permission from Elsevier.