Plathow C, Klopp M, Thieke C, Herth F, Thomas A, Schmaehl A, Zuna I, Kauczor HU.

Department of Nuclearmedicine, University of Freiburg, Hugstetter 55, 79106, Freiburg, Germany, christian.plathow@uniklinik-freiburg.de.

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 (κ=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 (κ=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.

Keywords: Mesothelioma – RECIST – MRI – Tumour volumetry – Validation

Ceresoli GL, Chiti A, Zucali PA, Cappuzzo F, De Vincenzo F, Cavina R, Rodari M, Poretti D, Lutman FR, Santoro A.

Department of Medical Oncology and Hematology, Istituto Clinico Humanitas IRCCS, Rozzano, Milan, Italy. giovanni_luca.ceresoli@humanitas.it

Abstract

Most patients with malignant pleural mesothelioma (MPM) are candidates for chemotherapy during the course of their disease. Assessment of the response with conventional criteria based on computed tomography (CT) measurements is challenging, due to the circumferential and axial pattern of growth of MPM. Such difficulties hinder an accurate evaluation of clinical study results and make the clinical management of patients critical. Several radiological response systems have been proposed, but neither WHO criteria nor the more recent RECIST unidimensional criteria nor hybrid uni- and bidimensional criteria seem to apply to tumor measurement in this disease. Recently, modified RECIST criteria for MPM have been published. Although they are already being used in current clinical trials, they have been criticized based on the high grade of inter-observer variability and on theoretical studies of mesothelioma growth according to non-spherical models. Computer-assisted techniques for CT measurement are being developed. The use of FDG-PET for prediction of response and, more importantly, of survival outcomes of MPM patients is promising and warrants validation in large prospective series. New serum markers such as osteopontin and mesothelin-related proteins are under evaluation and in the future might play a role in assessing the response of MPM to treatment.

Anna Wilkins^a, Sanjay Popat^a, Sarah Hughes^a and
Mary O’Brien^a
aDepartment of Medical Oncology, Royal Marsden Hospital, Sutton, SURREY SM2 5PT, United Kingdom
Received 18 July 2006; revised 1 February 2007; accepted 8 February 2007. Available online 2 April 2007.

Abstract

We report two cases of malignant pleural mesothelioma in first degree relatives arising within weeks of each other. The patients had a shared exposure to asbestos and age difference of over 20 years at time of presentation. In both cases, the anatomical pattern was similar and unusual for mesothelioma and initial histology was reported for both as non-small cell lung cancer. Both patients were treated with platinum-based combination chemotherapy.

Keywords: Malignant mesothelioma; Non-small cell lung cancer; Platinum-based combination chemotherapy

Abbreviations: CT, computed tomography; RECIST, response evaluation criteria in solid tumors; NF2, neurofibromatosis 2

Geoffrey R. Oxnard^a, Samuel G. Armato III^{b, d} and Hedy L. Kindler^{c, d}

^aDepartment of Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, United States
^bDepartment of Radiology, The University of Chicago, 5841 South Maryland Avenue, MC 2026, Chicago, IL 60637, United States
^cSection of Hematology/Oncology, Department of Medicine, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, United States
^dCancer Research Center, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, United States

Received 7 October 2005;  accepted 20 December 2005.  Available online 10 March 2006.

Abstract

Applicability of the Response Evaluation Criteria in Solid Tumors (RECIST) to the geometry of mesothelioma has been recently investigated. A “modified RECIST” measurement technique developed for mesothelioma proposes measurement of tumor thickness rather than maximum diameter. This study evaluated the volumetric consistency of the RECIST response criteria as applied to the modified RECIST measurement technique. Geometric models were developed to simulate mesothelioma growth, and measurements of these models were calculated. Relationships between change in model measurements and corresponding change in model volume were derived and evaluated. Application of the RECIST response criteria to the typical spherical tumor model results in partial response (PR) classification based on a 66% volume decrease and progressive disease (PD) based on a 73% volume increase; for mesothelioma model thickness measurements, the RECIST criteria result in PR classification based on a 30% volume decrease and PD based on a 20% volume increase. Alternative response criteria for mesothelioma thickness measurement (−66% for PR, +74% for PD) achieve volumetric equivalence with the RECIST criteria for spherical tumor measurement. Application of the RECIST response criteria to mesothelioma thickness measurements yields PR and PD classifications based on smaller volume changes than for spherical tumors.

Keywords: Mesothelioma; Response Evaluation Criteria in Solid Tumors (RECIST); Tumor measurement; Tumor response; Tumor volume

Schil PV.

Department of Thoracic and Vascular Surgery, University Hospital of Antwerp, Wilrijkstraat 10, B-2650 Edegem, Antwerp, Belgium. paul.van.schil@uza.be

Abstract

Malignant pleural mesothelioma has a very specific growth pattern invading the pleural surfaces and neighboring structures. For this reason precise estimation of tumor volume and description of local extension are particularly difficult. Different staging systems have been introduced, and the most widely used are discussed. Restaging of mesothelioma after induction therapy is even more complicated and still controversial. The recently described, modified response evaluation criteria in solid tumors (RECIST) criteria are presently the most accurate for response evaluation.