Predictors of survival following relapse or progression of small cell lung cancer. Southwest Oncology Group Study 8605 report and analysis of recurrent disease data base.

BACKGROUND: Survival after relapse or progression of small cell lung cancer (SCLC) is poor. The Southwest Oncology Group (SWOG) initiated a study of modulation of cyclophosphamide (Cy) resistance in this population. At study closure, the value of testing new regimens in previously treated patients was being debated nationally: Is there an independent impact of treatment over favorable prognostic factors? Thus, the authors analyzed the SWOG recurrent SCLC data base.

METHODS: A 12-hour infusion of cytosine arabinoside (ara-C) was used as a potential repair inhibitor of Cy-induced DNA damage in patients with relapsed SCLC. A data base of successive SWOG studies in recurrent SCLC was formed. The independent contribution to survival of prognostic factors, type of prior chemotherapy (CT), time from diagnosis, and type of CT on relapse were then assessed.

RESULTS: There were 3 partial responses observed in 67 patients, with substantial myelotoxicity. The median survival was 2.5 months, and 16% lived beyond 6 months. The multivariate analysis of the recurrent SCLC data base found that a normal lactate dehydrogenase (LDH) and second-line treatment with etoposide plus cisplatin (EP), if not initially treated with either alternating or complex multidrug regimens, were the only independent predictors of improved survival. The 2-year survival of this subset was 20%.

CONCLUSIONS: The Cy/ara-C program cannot be recommended for patients with recurrent SCLC. However, EP independently contributed to improved survival in patients without complex prior CT and a normal LDH. This finding supports future trials of new approaches in certain subsets of SCLC patients with limited prior treatment.