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 evaluation criteria for predicting the tumor progression-free survival (PFS) with that of RECIST 1.1 in non-small cell lung cancer (NSCLC) patients who were treated with bevacizumab.

MATERIALS AND METHODS: Sixteen patients (M:F = 11:5; median age, 57 years) treated with bevacizumab and combined cytotoxic chemotherapeutic agents were selected for a retrospective analysis. The tumor response was assessed by four different methods, namely, by using RECIST 1.1 (RECIST), RECIST but measuring only the solid component of tumor (RECISTsolid), the alternative method reflecting tumor cavitation (the alternative method) and the combined criteria (the combined criteria) that evaluated both the changes of tumor size and attenuation. To evaluate the capabilities of the different measurement methods to predict 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 different methods.

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) were 19%, 19%, 50% and 54%, respectively. Although statistically not significant, the alternative method showed the biggest difference for predicting PFS among the three response groups (PR, SD and PD) (p = 0.07). RECIST and the alternative method showed a significant difference for predicting the prognosis between the good (PR or SD) and poor overall responders (p = 0.02).

CONCLUSION: The response outcome evaluations using the three different CT response criteria that reflect tumor cavitation, the ground-glass opacity component and the attenuation changes in NSCLC patients treated with bevacizumab showed different results from that with using the traditional RECIST method.