Influence of histologic subtype of small cell carcinoma of the lung on clinical presentation, response to therapy, and survival.

Patients with small cell carcinoma of the lung (SCCL) were histologically subtyped according to the Working Party for Therapy of Lung Cancer classification and were treated with combination chemotherapy. Of the 103 patients studied, 54 had the lymphocyte-like (oat cell) subtype, 41 had the intermediate cell subtype, and 8 had a mixture of the two. No significant difference in initial performance status, extent of disease, chemotherapeutic response rate, or survival (median, 10.2 mo) was noted among the histologic subtypes. When the histologic subtype of the primary biopsy tissue was compared with the subtype of other pathology specimens from the same patient, concordance of subtype was present in 74% of the patients. In the remaining 26%, two or three histologic subtypes were present. This study demonstrates no clinically significant differences among the various histologic subtypes of SCCL in patients extensively staged and treated with aggressive cytotoxic therapy. Because of this and because concurrent biopsy tissues from multiple sites in the same patient may vary in subtype, we conclude that prognostic or therapeutic decisions should not be based on SCCL subtype.