Rationale for the use of chemotherapy in non-small cell lung cancer

The vast majority of patients have disseminated non-small cell lung cancer (NSCLC) at the time of diagnosis. Data from numerous studies clearly indicate that the disease is metastatic in asymptomatic patients who appear to have clinically resectable tumors. Adenocarcinoma is the histologic subtype that is most frequently metastatic, and its incidence appears to be increasing in a manner relative to other tumors. Of all of the prognostic factors, performance status appears to be most directly related to response rates. In other words, the higher the performance status, the higher the response rates. Tumor burden has been found to have an effect not only on performance status, but also on response to chemotherapy. Therefore systemic chemotherapy is urged as adjuvant treatment early in the course of NSCLC when performance status is highest and tumor burden lowest.