73: Segmentectomy for Primary Lung Cancer

Introduction

Segmentectomy was initially described by Churchill and Belsey¹ in 1939 for the treatment of bronchiectasis. Although the operation is still used to treat suppurative and other nonmalignant processes (e.g., aspergilloma, pulmonary sequestration), other pulmonary infections, pulmonary abscesses, and benign tumors of the lung (hamartomas, papillomas), this chapter concerns its controversial use in early-stage lung cancer.² Until 1950, pneumonectomy was the standard of care for lung cancer. However, increasing awareness of the diminution of respiratory function caused by pneumonectomy soon led to interest in lobectomy and other lesser resections for tumors of amenable size and location. In 1973, Jensik et al.³ reported the first series of segmentectomies for early-stage lung cancer. Since then, limited resection for lung cancer has been a topic of much debate, and the controversy has been plagued by conflicting results between studies comparing segmentectomy and standard lobectomy or pneumonectomy.

General Principles

Segmentectomy is an anatomic sublobar resection that involves the removal of functionally discrete units of the bronchovascular anatomy. The bronchovascular architecture is composed of a series of individual segments. Each segment has a pyramidal structure with its apex at the hilum and its base on the surface of the lung. Individually, the segments are supplied solely, with few collateral connections, by the following structures: (1) a segmental bronchus as a tertiary branch of the bronchial tree; (2) a segmental branch of the pulmonary artery (as well as the bronchial artery); and (3) a segmental (± intersegmental) branch of the pulmonary vein together with lymphatics. Each segment behaves as a discrete anatomical and functional unit that can be removed by segmental resection without affecting the functionality of the remaining lobe or adjoining bronchial segment. In properly selected patients with early-stage non–small-cell lung cancer (NSCLC), segmentectomy can achieve outcomes that are equivalent in overall survival to pneumonectomy and lobectomy.

A thorough knowledge of the human lung anatomy is mandatory for any surgeon undertaking this resection. There are 10 segments in the right lung (3 in upper lobe, 2 in middle lobe, and 5 in lower lobe) and 8 to 10 segments in the left lung (4–5 in upper lobe and 4–5 in lower lobe) (Fig. 73-1).