Interrater Agreement and Reliability of PERCIST and Visual Assessment When Using 18F-FDG-PET/CT for Response Monitoring of Metastatic Breast Cancer

Abstract

Response evaluation at regular intervals is indicated for treatment of metastatic breast cancer (MBC). FDG-PET/CT has the potential to monitor treatment response accurately. Our purpose was to: (a) compare the interrater agreement and reliability of the semi-quantitative PERCIST criteria to qualitative visual assessment in response evaluation of MBC and (b) investigate the intrarater agreement when comparing visual assessment of each rater to their respective PERCIST assessment. We performed a retrospective study on FDG-PET/CT in women who received treatment for MBC. Three specialists in nuclear medicine categorized response evaluation by qualitative assessment and standardized one-lesion PERCIST assessment. The scans were categorized into complete metabolic response, partial metabolic response, stable metabolic disease, and progressive metabolic disease. 37 patients with 179 scans were included. Visual assessment categorization yielded moderate agreement with an overall proportion of agreement (PoA) between raters of 0.52 (95% CI 0.44–0.66) and a Fleiss kappa estimate of 0.54 (95% CI 0.46–0.62). PERCIST response categorization yielded substantial agreement with an overall PoA of 0.65 (95% CI 0.57–0.73) and a Fleiss kappa estimate of 0.68 (95% CI 0.60–0.75). The difference in PoA between overall estimates for PERCIST and visual assessment was 0.13 (95% CI 0.06–0.21; p = 0.001), that of kappa was 0.14 (95% CI 0.06–0.21; p < 0.001). The overall intrarater PoA was 0.80 (95% CI 0.75–0.84) with substantial agreement by a Fleiss kappa of 0.74 (95% CI 0.69–0.79). Semi-quantitative PERCIST assessment achieved significantly higher level of overall agreement and reliability compared with qualitative assessment among three raters. The achieved high levels of intrarater agreement indicated no obvious conflicting elements between the two methods. PERCIST assessment may, therefore, give more consistent interpretations between raters when using FDG-PET/CT for response evaluation in MBC.

Clinical Impact of FDG-PET/CT Compared with CE-CT in Response Monitoring of Metastatic Breast Cancer

“…Since our results were part of the clinical routine, a standardized set of response criteria such as PERCIST was not applied for FDG-PET/CT. However, we showed in previous studies that the clinical application of PERCIST is feasible [29] and has the potential to increase the level of inter-observer agreement and reliability when compared with qualitative visual assessment [30].…”

Comparison of Image Quality and Quantification Parameters between Q.Clear and OSEM Reconstruction Methods on FDG-PET/CT Images in Patients with Metastatic Breast Cancer

“…It has also been reported that PERCIST has high applicability [ 16 ], has a higher level of overall interrater agreement and reliability compared with a qualitative assessment [ 35 , 36 ], and is superior in the detection of new lesions or unequivocal progression in nontarget lesions [ 37 ]. Therefore, clinical implementation of the PERCIST assessment may improve the prognostic stratification [ 15 , 37 , 38 ] and provide a standardized approach independent of interpreters and reconstruction methods.…”

2-[18F]FDG-PET/CT is a better predictor of survival than conventional CT: a prospective study of response monitoring in metastatic breast cancer

“…Standardized response evaluation criteria were applied for both modalities. For 2-[ 18 F]FDG-PET/CT, PERCIST was considered an established semiquantitative assessment with a significantly higher interrater agreement and reliability than qualitative assessment 11 , 12 , 22 , 23 .…”