At the time of preparation and printing of the seventh edition of this text, the staging system in effect for lung cancer was the one in the American Joint Commission on Cancer (AJCC) Cancer Staging Manual, sixth edition. In mid-2009, the next edition of the staging manual will be released and will have considerable changes both for tumor size and for nodal involvement. In addition, accommodations have been made for lesions within the same lobe and for malignant pleural effusions.