Separation of small-cell from non-small-cell lung cancer. The Southeastern Cancer Study Group pathologists' experience.

We reviewed the pathology materials from 691 patients with lung cancer who participated in therapy protocols with the Southeastern Cancer Study Group. We found good agreement (94%) between pathologists over the separation of small-cell carcinomas from non-small-cell carcinomas. Thus, oncologists and cooperative groups should rely on their local pathologists' diagnoses for the major choices of therapies in lung cancer and realize that there remain a small number of overlapping tumors that are not uniformly diagnosed by routine light microscopy and that require more sophisticated techniques if their diagnosis is to be accurate.