Prognostic Significance of Laboratory Parameters Measured at Diagnosis in Small Cell Carcinoma of the Lung

An analysis of prognostic factors in small cell lung cancer has been carried out using data from 371 patients treated with identical chemotherapy in the context of a large prospectively randomized clinical trial. Prognosis was shown to be strongly correlated with initial performance status, disease extent, and routine biochemical tests at the time of diagnosis. Plasma albumin, plasma sodium, alkaline phosphatase, and gamma-glutamyl transpeptidase were all predictive of survival. An initial hemoglobin of less than 11 g/dl was also predictive, but age, sex, and initial WBC count were not. A multiple regression analysis identified performance status, plasma alkaline phosphatase, plasma sodium, disease extent, and plasma albumin as contributing independently to survival. Using these parameters, three prognostic groupings could be defined. The combination of performance status and the biochemical values more closely predicted survival than categorization on the basis of disease extent defined by clinical, radiological, and scanning criteria. Response to chemotherapy was strongly correlated with these prognostic groupings. A much higher response rate occurred in patients in the best prognostic category in whom the tumor mass is assumed to be smaller. These results provide a simple basis for predicting prognosis in small cell lung cancer and indicate that the better prognosis in chemotherapy responders is not solely due to the treatment.