Positron emission tomography-CT evaluation of therapeutic effect on lung cancer: a comparative study / 中华放射学杂志

ABSTRACT

Objective To compare the PET response criteria in solid tumors (PERCIST) and response evaluation criteria in solid tumors (RECIST) in the evaluation of therapeutic response in 49 non-small-cell lung cancer(NSCLC) patients.Methods Forty-nine NSCLC patients who received chemotherapy but no surgery were studied.Therapeutic responses were evaluated using 18 F-FDG PET and CT according to the RECIST and PERCIST methods.The PET-CT scans were obtained before chemotherapy and about 2 or 6 weeks after completion of chemotherapy.Firstly the reduction rates of tumor diameter and reduction rates of tumor standardized uptake value were compared with paired t-test.Then the response was classed into 4 levels according to RECIST and PERCISTPD and PMD =1,SD and SMD =2,PR and PMR =3,CR and CMR =4.Pearson and Chi-square test was used to compare the proportion of four levels in RECIST and PERCIST.Finally one target lesion and two target lesions were compared for RECIST therapeutic evaluation in 33 cases with two target lesions.Results The diameter was (3.52 ± 1.65) cm before the therapy and (2.39 ± 1.43)cm after the therapy.The standardized uptake value was 8.78 ±4.18 vs.5.06 ±3.62 before and after therapy for the first target lesions in 49 patients.The differences of reduction rates between tumor diameter and standardized uptake value were not significant because of selection bias (0.32 ± 0.27 vs.0.28 ±0.64,t =0.176,P ＞0.05).However,there was a significant difference when the reduction rate was compared only in 39 patients in which the standardized uptake values were reduced after therapy (0.39 ± 0.29 vs.0.52 ±0.28,t =-4.08,P ＜0.01).The results of classification were 1/13 for CR/CMR,25/16 for PR/PMR,22/15 for SD/SMD,1/5 for PD/PMD,and 33 cases had no consistent results from RECIST and PERCIST.There was a significant difference in response classification between RECIST and PERCIST (x2 =16.252,P ＜ 0.01).No significant difference was found between one target lesion and two target lesions for RECIST evaluation results in 33 cases (x2 =1.171,P ＞ 0.05),but results of response classification were changed in 5 cases.Conclusions PERCIST criteria may be more sensitive in NSCLC therapeutic evaluation comparing to RECIST criteria.There is a higher proportion with CMR and PMD in PERCIST,but its effect on the prognosis is not yet clear.The number of target lesions may affect the results of therapeutic evaluation with RECIST criteria.