Molecularly targeted therapy using bevacizumab for non-small cell lung cancer: a pilot study for the new CT response criteria

Objective: We wanted to compare the efficacy of the new CT response evalua-tion criteria for predicting the tumor progression-free survival (PFS) with that ofRECIST 1.1 in non-small cell lung cancer (NSCLC) patients who were treatedwith bevacizumab. Materials and Methods: Sixteen patients (M:F = 11:5; median age, 57 years)treated with bevacizumab and combined cytotoxic chemotherapeutic agentswere selected for a retrospective analysis. The tumor response was assessed byfour different methods, namely, by using RECIST 1.1 (RECIST), RECIST butmeasuring only the solid component of tumor (RECISTsolid), the alternativemethod reflecting tumor cavitation (the alternative method) and the combined cri-teria (the combined criteria) that evaluated both the changes of tumor size andattenuation. To evaluate the capabilities of the different measurement methods topredict the patient prognosis, the PFS were compared, using the log rank test,among the responder groups (complete response [CR], partial response [PR],stable disease [SD] and progressive disease [PD]) in terms of the four differentmethods. Results: The overall (CR, PR or SD) response rates according to RECIST,RECISTsolid, the alternative method and the combined criteria were 81%, 88%,81% and 85%, respectively. The confirmed response rates (CR or PR) were19%, 19%, 50% and 54%, respectively. Although statistically not significant, thealternative method showed the biggest difference for predicting PFS among thethree response groups (PR, SD and PD) ( p = 0.07). RECIST and the alternativemethod showed a significant difference for predicting the prognosis between thegood (PR or SD) and poor overall responders ( p = 0.02). Conclusion: The response outcome evaluations using the three different CTresponse criteria that reflect tumor cavitation, the ground-glass opacity compo-nent and the attenuation changes in NSCLC patients treated with bevacizumabshowed different results from that with using the traditional RECIST method. ccurately assessing the changes of the tumor burden is important whenconducting cancer therapy, and so much effort has been directed towardthe development of standardized and reproducible methods for evaluat-ing the response of tumors. The Initial Response Evaluation Criteria in Solid Tumors(RECIST) published in 2000 (1) has been widely used in the scientific oncologycommunity. The revised RECIST guidelines (version 1.1) were developed for currentuse (2). However, a number of questions and issues (e.g., tumor size changes only, notconsidering various morphologic changes within the target lesions with treatment)have been raised about the use of the traditional tumor response criteria, including theHo Yun Lee, MD