Small cell lung cancer is a tumor that initially responds to chemotherapy and radiotherapy, however, it is associated with very poor prognosis since the initial response is nearly always followed by relapse and metastasis. The response to subsequent therapy is very limited as is the duration of response in these patients. Patients with SCLC have high rates of metastases at presentation suggesting that angiogenesis is particularly important in this cancer, furthermore studies have shown that microvessel density and VEGF expression in SCLC tumor samples correlate with development of metastases and poor prognosis. Furthermore VEGF expression was the only factor that retained a significant inverse correlation with survival when assessed in a multivariate analysis.