Analysis of a pathology review of patients with lung tumors.

The rates of agreement and patterns of disagreement in the classification of lung tumors were evaluated for a pathology panel review of 476 patients with lung cancer. The panel review consisted of three independent diagnoses made in accordance with the criteria of the Working Party for Therapy of Lung Cancer. At least two of the three pathologists agreed as to the major cell classification in 94% of the patients. In 67% of the evaluations, there was agreement among the three pathologists. Small-cell carcinoma and epidermoid carcinoma were the most consistently evaluated classes, followed by adenocarcinoma and large-cell carcinoma. The poorly differentiated categories provided the greatest source of difficulty in discriminating among major histologic classes. For an initial diagnosis of large-cell carcinoma, 14% of the second classifications were poorly differentiated epidermoid carcinoma, and 20% were poorly differentiated adenocarcinoma. For an initial diagnosis of small-cell carcinoma, 11% of the second independent evaluations classified the carcinoma as other than small-cell. The most likely alternative diagnosis was large-cell carcinoma (5%).