Morphologic and clinical determinants of response to therapy in small cell carcinoma of the lung.

The authors reviewed a series of 29 cases of small cell carcinoma of the lung in order to determine the influence of histologic type and other prognostic factors on response to combination chemotherapy and survival. Comparing classical (lymphocyte-like and fusiform) versus nonclassical histologic types (polygonal and other), no significant difference could be found in response to therapy (CR + PR 11/16 versus 8/11), median survival (7 versus 6 months) or median survival of responders (9 versus 10 months). Furthermore, tumors with atypical histology ("other") behaved similar to the overall series. Of clinical factors investigated, only decreased performance status and presence of metastatic disease were significant prognostic indicators. The results suggest that tumor histologic type is not a useful prognostic indicator in small cell carcinoma, and that atypical tumors resembling small cell carcinoma appear to respond similarly to classical small cell carcinoma and should probably be treated as such.