The impact of tumor size change after target therapy on survival: analysis of patients enrolled onto three clinical trials of advanced NSCLC from one institution.

PURPOSE: To explore whether changes in tumor size impact survival in advanced non-small-cell lung cancer (NSCLC) after target therapy, especially in patients with evaluation of stable disease (SD), and to review the applicability of the Response Evaluation Criteria in Solid Tumors (RECIST) criteria in target therapy.

PATIENTS AND METHODS: Data from 88 NSCLC patients receiving gefitinib (250 mg, daily [qd]), erlotinib (150 mg, qd), and ZD6474 (100 mg, qd) in three clinical trials (IRESSA registration clinical trial, TRUST study, ZD6474 study) during November 2003 to June 2005 were retrospectively analyzed. The treatment effect (complete response, partial response, stable disease [SD], or progressive disease) was evaluated with radiologic assessment according to the RECIST criteria. SD patients were divided into two groups: SD-/0, in which the sum of the longest diameter of target lesions decreased by less than 30% or did not change; and SD+, in which the sum of the longest diameter of target lesions increased by less than 20%. The differences of progression-free survival (PFS) and overall survival (OS) between these groups were analyzed.

RESULTS: In the whole group, 27 patients achieved complete response or partial response as best response, 40 achieved SD, and 22 had progressive disease. The median PFS and OS were 4 months and 11.1 months, respectively. In SD patients, 27 were SD-/0 and 13 patients were SD+. The PFS and OS of SD+ patients was shorter than that of SD-/0 patients (5.65 months vs 2.03 days, P < 0.001 and 12.2 months vs 7.1 months, P < 0.001).

CONCLUSION: The applicability of RECIST criteria was called into question in the evaluation of target therapy. Change in tumor size might predict survival in advanced NSCLC patients with target therapy and may be a surrogate endpoint for efficacy in target therapy.