Tumor size, response rate, and prognosis in small cell carcinoma of the bronchus treated by combination chemotherapy.

Ninety-eight patients with small cell carcinoma of the bronchus (SCCB) were treated with a combination of cyclophosphamide, methotrexate with calcium leucovorin rescue, and lomustine (CCNU). VP-16-213 was given on relapse. Response rate and survival were analyzed according to extent of tumor, presence of the syndrome of inappropriate antidiuretic hormone production (SIADH), and, in 38 patients, size of intrathoracic tumor as measured by computerized tomographic (CT) scanning. The median survival of the entire group was 34.6 weeks. In patients with limited disease the median survival was 46 weeks compared to 29 weeks for those with extensive disease. This difference in survival between patients with limited and extensive disease was most marked in those showing a partial response (median survival, 45.9 and 28 weeks, respectively). Patients with ectopic antidiuretic hormone production had a poor prognosis even if they had achieved a complete response. Only one partial response to VP-16-213 occurred. There was a strong correlation between initial intrathoracic tumor size as assessed by total cross-sectional area on CT scan and response and survival. When the total area exceeded 30 cm2 there were no complete responders, but there were complete responses in eight of 21 patients when the area was less than 30 cm2. The relationship between intrathoracic tumor size and response rate was present when analyzed according to disease extent, age, sex, and performance status. A clear relationship between total tumor area and survival was also found. When SCCB is treated with chemotherapy alone, the prognosis is better for those patients who present with limited disease, without SIADH, and with small intrathoracic tumor. In this group it is possible that further intensification of therapy may result in prolonged survival.