Introduction

Lung cancer remains the leading cause of cancer-related death in North America and Europe, and more people die of lung cancer than colon, breast, and prostate cancer combined. During 2000, there were predicted to be about 164 100 new cases of lung cancer, 89 500 men and 74 600 women. The increase in death rate is slowing, but has not begun to drop.

More than 80% of lung cancer deaths are attributable to smoking, and only asbestos exposure and family history enhance risk substantially. Fundamentally, lung cancer occurs as a result of deregulation of normal gene expression. Molecular changes that have been demonstrated in lung cancer include activation of oncogenes such as ras, myc, bcl-2, and c-erbB-2; loss of tumor suppressor genes such as p53, RB, and p16; and alterations in angiogenesis such as vascular endothelial growth factor (VEGF) overexpression in primary lung tumors. All represent potential therapy targets.

Categories/staging

The diagnosis is established by examination of either cytology or surgical pathology specimens. Lung cancer is rarely if ever treated without a specific tissue diagnosis. The most widely accepted histologic classification for lung tumors is that proposed by the World Health Organization (WHO) and revised in 1999. It includes four major types: squamous cell, adenocarcinoma, small cell, and large cell.

Small cell lung cancer (SCLC) is the more aggressively spreading tumor with neuroendocrine features and accounts for 20% of all lung cancers.