ABSTRACT
BACKGROUND: The criterion of two target lesions per organ in the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 is an arbitrary one, being supported by no objective evidence. The optimal number of target lesions per organ still needs to be investigated. We compared tumor responses using the RECIST 1.1 (measuring two target lesions per organ) and modified RECIST 1.1 (measuring the single largest lesion in each organ) in patients with small cell lung cancer (SCLC). METHODS: We reviewed medical records of patients with SCLC who received first-line treatment between January 2004 and December 2014 and compared tumor responses according to the two criteria using computed tomography. RESULTS: There were a total of 34 patients who had at least two target lesions in any organ according to the RECIST 1.1 during the study period. The differences in the percentage changes of the sum of tumor measurements between RECIST 1.1 and modified RECIST 1.1 were all within 13%. Seven patients showed complete response and fourteen showed partial response according to the RECIST 1.1. The overall response rate was 61.8%. When assessing with the modified RECIST 1.1 instead of the RECIST 1.1, tumor responses showed perfect concordance between the two criteria (k=1.0). CONCLUSIONS: The modified RECIST 1.1 showed perfect agreement with the original RECIST 1.1 in the assessment of tumor response of SCLC. Our result suggests that it may be enough to measure the single largest target lesion per organ for evaluating tumor response.
ABSTRACT
UNLABELLED: Background : The impact of the RECIST 1.1 on the selection of target lesions and assessment of tumor response was not evaluated in patients with advanced NSCLC who received cytotoxic chemotherapy. METHODS: We reviewed medical records of patients with advanced NSCLC who received first-line chemotherapy between January 2004 and December 2013 and compared the selection of target lesions and tumor responses using the two RECIST versions. RESULTS: A total of 88 patients who had at least one target lesion according to the RECIST 1.0 were included in the study. The number of target lesions by the RECIST 1.1 was significantly lower than that by the RECIST 1.0. When adopting the RECIST 1.1 instead of the RECIST 1.0, 40 patients (45.4%) showed a decrease in the number of target lesions. Three patients no longer had target lesion because of the new lymph node (LN) criteria of the RECIST 1.1. Tumor responses showed a high level of concordance between the RECIST 1.0 and RECIST 1.1, with a kappa value of 0.912. Four patients (4.5%) showed disagreement of tumor responses between the two criteria, which were all due to the change of the LN criteria. CONCLUSION: The RECIST 1.1 showed a high level of concordance with the RECIST 1.0 in the assessment of tumor response in advanced NSCLC patients treated with cytotoxic chemotherapy. The new LN criteria were the major cause of the reduction of target lesions and reclassification of the tumor response.
