Isolated pleural effusion in small cell lung carcinoma: Favorable prognosis. A review of the Southwest Oncology Group experience

The currently accepted staging system for small cell lung cancer considers patients who present with a pleural effusion as having extensive disease, but no series of such patients had been reported. Between 1974 and 1980, 56 patients with ipsilateral pleural effusion as the only evidence of metastatic spread beyond the primary tumor and regional nodes were placed on three consecutive Southwest Oncology Group studies of chemotherapy and radiation therapy for small cell lung cancer. Effusions were cytology-positive in 24: response rates and survival were not different whether cytology was positive or negative. The overall response rate was 77 percent, with 36 percent who achieved complete response, a result comparable to that for patients with limited disease. The survival of effusion 'only' patients did not differ significantly among the studies. Median survival of 54 weeks and survival curve for the effusion 'only' group as a whole was identical to that of all patients classed as having limited disease by the usual criteria. Long-term disease-free survival was observed just as commonly: 2/17 patients from the first study have disease-free survival at greater than five years, and overall disease-free survival at greater than two years is 22 percent. Performance status does not explain the favorable survival in this subgroup, since only 55 percent of effusion patients were fully ambulatory (comparable to extensive disease patients as a group) and even fully ambulatory patients with extensive disease rarely had disease-free survival greater than two years. Patients with ipsilateral pleural effusion as their only evidence of metastasis should be staged as having limited disease.