Therapy response in malignant pleural mesothelioma-role of MRI using RECIST, modified RECIST and volumetric approaches in comparison with CT

Abstract

To evaluate and compare early therapy response according to RECIST (response evaluation criteria in solid tumours) and modified RECIST criteria using MRI techniques in patients with malignant pleural mesothelioma (MPM) in comparison with CT. Fifty patients with MPM (32 male/18 female) were included in this study. Early therapy response was evaluated after 9 weeks [three of six chemotherapy (CHT)] cycles. Additionally patients were examined before chemotherapy, 4 weeks after early therapy response evaluation and after six cycles to evaluate diagnostic follow-up. RECIST and modified RECIST criteria were applied using CT and MRI (HASTE, VIBE, T2-TSE sequences). In MRI additionally a volumetric approach measuring tumour weight (overall segmented tumour volume) was applied. Additionally vital capacity (VC) was measured for correlation. Image interpretation was performed by three independent readers independently and in consensus. The 'gold standard' was follow-up examination. Twenty-eight patients showed partial response, 12 patients stable disease and 10 patients progressive disease at early therapy response evaluation. In the follow-up these results remained. For MRI, in 46 cases patients were identically classified using RECIST and modified RECIST criteria. Modified RECIST criteria were identically classified as gold standards in all cases, whereas using RECIST criteria in four cases there was a mismatch (partial response vs. stable disease). Modified RECIST kappa values showed better interobserver variability compared with RECIST criteria (kappa=0.9-1.0 vs. 0.7-1.0). For CT, in 44 cases patients were identically classified using RECIST and modified RECIST criteria. Modified RECIST criteria were identically classified as in gold standards in 48 out of 50 patients, whereas using RECIST criteria in 6 cases there was a mismatch (partial response vs. stable disease). Modified RECIST kappa values showed better interobserver variability compared with RECIST criteria (kappa=0.9-1.0 vs. 0.6-1.0). Modified RECIST criteria especially in combination with high-resolution MRI is a very accurate and reproducible technique to correctly evaluate early therapy response in MPM.

Comparison of diffusion‐weighted MRI and MR volumetry in the evaluation of early treatment outcomes after preoperative chemoradiotherapy for locally advanced rectal cancer

“…The patients with tumoral downstaging were classified as the responder group. Second, according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST) and World Health Organization (WHO) criteria for imaging-based treatment response evaluation, a partial response (PR) was defined as a 65% decrease in lesion volume (10,17). Therefore, patients with a late tumor volume reduction rate of >65% were classified as responders.…”

“…Although tumor volumetry is an operator-dependent and time-consuming semiautomatic technique, the volumetric evaluation may have better accuracy and reproducibility than the classic approach of tumor diameter measurement (10). The accurate assessment of tumor volume reduction and downstaging might enable of a local excision or a nonsurgical approach to be considered in patients who have a good probability of anal sphincter preservation or a good tumor response after preoperative CRT (11,12).…”

Staged Surgical Treatment in an Infant with Huge Aortopulmonary Window Presenting with Severe Pulmonary Hypertension and Recurrent Pulmonary Infection

“…In order to stage MPM and decide on treatment options, imaging modalities such as MSCT, MRI, and positron emission tomography-computed tomography (PET-CT) are employed (8,9). Due to the diffusion of water molecules in tissues, DWI can reveal tissue characteristics.…”

Volumetric assessment in malignant pleural mesothelioma

“…Therefore, there is a greater emphasis on determining resectability rather than an attempt at clinical staging in these patients. If deemed unresectable, serial imaging with CT or PETCT to determine response to therapy by comparing differences in uptake and tumor measurements is often done (21)(22)(23)(24)(25).…”

“…Tumor volume measurements from cross sectional imaging have been compared to other quantitative methods of therapy response measurement in MPM. Plathow et al measured MPM tumor volume on 50 patients and compared it to RECIST and modified RECIST in patients undergoing chemotherapy, finding that tumor volume measured on MRI is a good prognostic indicator and metric of treatment response or failure (24). Tumor volume measurement on CT has similarly been found to be useful in assessing treatment response.…”