Problems in Pathologic Staging of Lung Cancer

Abstract Context.—Tumor stage is the most important prognostic and predictive factor for patients with lung cancer, the most lethal neoplasm in the United States. It is used by thoracic surgeons, radiation therapists, and oncologists to determine whether patients with these neoplasms will be treated surgically with curative intent or with palliative radiation therapy and/or chemotherapy. Objective.—To review the variety of practical problems that can arise during the assessment of the pathologic stage and other prognostic/predictive factors included in the College of American Pathologist checklist for evaluation of resected lung neoplasms. Data Sources.—Potential practical difficulties that can arise during the pathologic staging of lung cancer patients include the distinction between pT1, pT2, and pT3 lesions based on their location and the presence of visceral pleura and/or parietal pleura invasion; the differential diagnosis between multiple synchronous or metachronous primary lung neoplasms (pT1m) and intrapulmonary metastasis of non-small cell carcinoma of the lung (pT4 or pM1 according to their location); and the role of the recent American Joint Committee on Cancer terminology for the classification of lymph nodes (isolated tumor cells, micrometastases, and metastases). Conclusions.—The variety of practical problems that can arise during the assessment of important prognostic and predictive features such as resection margin status and evaluation of lymphovascular invasion are reviewed. A brief discussion of the assessment of the effects of neoadjuvant therapy on resected lung neoplasms is also included.