Staging and response to therapy of malignant pleural mesothelioma

Pleural Neoplasms-What Could MRI Change?

The primary pleural neoplasms constitute around 10% of the pleural tumors. The currently recommended method for their imaging is CT which has been shown to have certain limitations. Strong development of the MRI within the last two decades has provided us with a number of sequences that could potentially be superior to CT when it comes to the pleural malignancies' detection and characterization. This literature review discusses the possible applications of the MRI as a diagnostic tool in patients with pleural neoplasms. Although selected MRI techniques have been shown to have a number of advantages over CT, further research is required in order to confirm the obtained results, broaden our knowledge on the topic, and pinpoint the sequences most optimal for pleural imaging, as well as the best methods for reading and analysis of the obtained data.

"The Less I Think About It, the Better I Feel": A Thematic Analysis of the Subjective Experience of Malignant Mesothelioma Patients and Their Caregivers

Aim: A cancer diagnosis-and in particular a Malignant Mesothelioma (MM) one-breaks the somatopsychic balance of the individual, compromising the quality of residual life and giving rise to many negative emotions difficult to integrate and to elaborate (such as depression, fears, anxieties, hopelessness, guilt, shame, and rage). Several national and international guidelines acknowledged the importance of evaluating psychological and socio-relational features in MM patients and their caregiver. However, only few studies have investigated the subjective experience of MM patients and even less research has focused on the caregivers' experience. Thus, the aim of the present study is to investigate the lived experience of both MM patients and their caregivers, providing an in-depth comprehension of the psychological sequelae of the disease. Materials and Methods: Within a psychoanalytically-informed conceptual framework, open-ended interviews were conducted with 10 MM patients and 9 caregivers. Thematic analysis was employed: interviews were audio-recorded, transcribed verbatim, and coded in order to identify the main recurring themes across the narratives. Results: We detected four different themes: (1) bodily symptoms and embodied emotions; (2) living in or near a National Priority Contaminated Site (NCPS); (3) "nothing is like it was" (that is, the impact of the diagnosis on everyday life, the changes it causes in the family relationships, the things that are still possible to do, the mourning process); (4) "what will become of us?" (that is, worries about the impact of the diagnosis on the beloved ones, death and legacy). Discussion: MM patients and caregivers seem to be stuck in a concrete mental functioning focused on symptoms and they find it difficult to openly think and talk about the affective and emotional consequences of the diagnosis. Alongside this, they express the need to find new and less conflictual ways to stay together and talk to each other during the period of active treatments for the illness (i.e., chemotherapy, radiotherapy, etc) and the end-of-life. The results of this study have important implications for the clinical management of MM and can help develop multi-professional specialist interventions addressed to both patients and caregivers.

Volumetric assessment in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a highly malignant pleural neoplasm with a dismal prognosis. Multimodality approach including surgery and chemotherapy are utilized to treat patients with resectable disease. Clinical staging allows for selection of patients for treatment strategies, but has not been found to be prognostic and is plagued by high interobserver variability. Tumor volume measurement on cross-sectional imaging has emerged as a potential quantitative tool with prognostic significance. This review focuses on volumetric assessment from cross-sectional imaging (CT, MRI, ¹⁸F-FDG PET/CT) and the potential prognostic benefit and applications.

Iron overload as a major targetable pathogenesis of asbestos-induced mesothelial carcinogenesis

Few people expected that asbestos, a fibrous mineral, would be carcinogenic to humans. In fact, asbestos is a definite carcinogen in humans, causing a rare but aggressive cancer called malignant mesothelioma (MM). Mesothelial cells line the three somatic cavities and thus do not face the outer surface, but reduce the friction among numerous moving organs. MM has several characteristics: extremely long incubation period of 30-40 years after asbestos exposure, difficulty in clinical diagnosis at an early stage, and poor prognosis even under the current multimodal therapies. In Japan, 'Kubota shock' attracted considerable social attention in 2005 for asbestos-induced mesothelioma and, thereafter, the government enacted a law to provide the people suffering from MM a financial allowance. Several lines of recent evidence suggest that the major pathology associated with asbestos-induced MM is local iron overload, associated with asbestos exposure. Preclinical studies to prevent MM after asbestos exposure with iron reduction are in progress. In addition, novel target genes in mesothelial carcinogenesis have been discovered with recently recognized mesothelioma-prone families. Development of an effective preventive strategy is eagerly anticipated because of the long incubation period for MM.

[Usefulness of 18F-FDG PET-CT in the presurgical assessment of malignant pleural mesothelioma treated with neoadjuvant chemotherapy]

Malignant pleural mesothelioma is a relatively rare, but highly aggressive, tumor, associated to exposure to asbestos, with a life expectancy between 9 and 17 months. Chest pain and dyspnea are the most frequent symptoms. The most commonly used therapy is surgery accompanied by chemotherapy. Preoperative assessment, after chemotherapy, has been done using magnetic resonance imaging and computed tomography (CT). However, these techniques cannot predict early response to therapy, because of the slow structural change of the tumor. The aim of this case report is to review and learn about the growing use of PET-CT imaging with (18)F-FDG in the preoperative staging of malignant pleural mesothelioma and its influence in selecting the most appropriate type of surgery.

Computerized segmentation and measurement of malignant pleural mesothelioma

PURPOSE

The current linear method to track tumor progression and evaluate treatment efficacy is insufficient for malignant pleural mesothelioma (MPM). A volumetric method for tumor measurement could improve the evaluation of novel treatments, but a fully manual implementation of volume measurement is too tedious and time-consuming. This manuscript presents a computerized method for the three-dimensional segmentation and volumetric analysis of MPM.

METHODS

The computerized MPM segmentation method segments the lung parenchyma and hemithoracic cavities to define the pleural space. Nonlinear diffusion and a k-means classifier are then implemented to identify MPM in the pleural space. A database of 31 computed tomography scans from 31 patients with pathologically confirmed MPM was retrospectively collected. Three observers independently outlined five randomly selected sections in each scan. The Jaccard similarity coefficient (J) between each of the observers and between the observer-defined and computer-defined segmentations was calculated. The computer-defined and the observer-defined segmentation areas (averaged over all observers) were both calculated for each axial section and compared using Bland-Altman plots.

RESULTS

The median J value among observers averaged over all sections was 0.517. The median J between the computer-defined and manual segmentations was 0.484. The difference between these values was not statistically significant. The area delineated by the computerized method demonstrated variability and bias comparable to the tumor area calculated from manual delineations.

CONCLUSIONS

A computerized method for segmentation and measurement of MPM was developed. This method requires minimal initialization by the user and demonstrated good agreement with manually drawn outlines and area measurements. This method will allow volumetric tracking of tumor progression and may improve the evaluation of novel MPM treatments.

Surgical assessment of malignant pleural mesothelioma: have we reached a critical stage?

OBJECTIVE

The International Mesothelioma Interest Group (IMIG) classification is the most widely used staging system but is based on post-resectional parameters. We aimed to test the association between clinical and pathological staging and to identify possible discrepancies.

METHODS

We identified 164 consecutive patients (144 males and 20 females, with mean age 58 years) who underwent radical surgery (114 extrapleural pneumonectomy; 50 radical pleurectomy/decortication) for malignant pleural mesothelioma (MPM). The patients were clinically staged with CT + or - MRI (CT, computed tomography; MRI, magnetic resonance imaging).

RESULTS

Clinical T (cT) stage proved to be the same as pathological T (pT) stage in 44%; understaged in 46% and overstaged in 10%. Clinical N (cN) stage proved to be the same as pathological N (pN) stage in 56%; understaged in 31% and overstaged in 13%. Disease-free interval (DFI) was associated with cT stage (median DFI 29 months, SE 13, 95% CI 3-54 months for cT1; median 5, SE 3, 95% CI 3-6 months for cT4, p=0.02) but not clinical N stage (median DFI 12 months, SE 1, 95% CI 9-15 months for cN0; median DFI 11 months, SE 0.3, 95% CI 10-12 months for cN2, p=0.5) and was associated with both pT (median DFI 31 months, SE 17, 95% CI 0-64 months for pT1; median DFI 8 months, SE1, 95% CI 6-11 months for pT4, p=0.03) and pN stage (median DFI 14 months, SE 3, 95% CI 9-20 months for pN0; median DFI 10 months, SE 1, 95% CI 8-13 months for pN2, p=0.02). Overall survival was associated with cT stage (median survival 25 months, SE 3, 95% CI 20-30 months for cT1; median survival 11 months, SE 3, 95% CI 10-11 months for cT4, p=0.01) but not cN stage (median survival 15 months, SE 2, 95% CI 11-19 months for cN0; median survival 15 months, SE 2, 95% CI 12-19 months for cN2, p=0.49) and pN stage (median survival 22 months, SE 3, 95% CI 19-27 months for pN0; median survival 14 months, SE 1, 95% CI 12-17 months for pN2, p=0.01) but not pT stage (median survival 27 months, SE 4, 95% CI 19-35 months for pT1; median survival 12 months, SE 2, 95% CI 9-15 months for pT4, p=0.06). Pathological IMIG stage was associated with DFI and overall survival; however, preoperative IMIG stage was less useful.

CONCLUSIONS

There are deficiencies in the current staging system for MPM and discrepancies between clinical and pathological systems. Future improvements are needed in clinical descriptors of nodal status and pathological descriptors of T stage. Subsequent IMIG stage grouping also needs revision.

Making the case for molecular staging of malignant pleural mesothelioma

Malignant pleural mesothelioma is an aggressive malignancy for which surgical treatment is an option for a subset of patients. A gene ratio test based on the relative expression levels of four genes has been validated in clinical trials to predict which patients will benefit from surgical therapy. A description of the test properties and the independent predictors for outcome are provided.

RECIST revisited: a review of validation studies on tumour assessment

The response evaluation criteria in solid tumours (RECIST) was developed in the late 1990s to replace the WHO criteria for response evaluation. The new criteria included important changes such as unidimensional tumour measurement, selection of target lesions with a minimum size, details concerning imaging modalities and a new threshold for assignment of objective progression. RECIST was published in February 2000 and very quickly came into operation first in clinical trials performed under the auspices of EORTC, US NCI or NCI Canada Clinical Trials Group but was adopted quickly thereafter by the entire cancer clinical research community. As several key features of RECIST were based on analysis of retrospective clinical data, it was felt important to carefully monitor the implementation of the guidelines and stimulate prospective validation studies. This paper reviews the literature that has been published on RECIST from 2000 up to November 2005. In total 60 papers and ASCO, abstracts directly refer to research studies or reviews related to RECIST and its implementation. Amongst the 60 references identified for this review, 11 papers refer to validation studies (seven prospective and four retrospective), six papers refer to the comparison of unidimensional measurements versus bi or tri-dimensional measurements, 12 papers address issues raised with the implementation of RECIST in Mesothelioma and Gastro-Intestinal Stromal Tumours and four papers report on an adaptation of RECIST for specific tumour types. In general, RECIST has been well received by the scientific community and most validation studies fully support the implementation of the new criteria. As expected, however, some issues have been identified. In keeping with the mathematical differences in definition of progression, RECIST delays the identification of progression as compared to WHO criteria in some instances. RECIST criteria are not easily applicable in some types of trials such as those in paediatric tumours and in mesothelioma. Furthermore, anatomical changes in the tumour as described by RECIST may be detected later than functional changes in some circumstances, as for example in Gastro-Intestinal Stromal Tumours treated with Imatinib. However, there is no other universal method of tumour assessment as yet and functional imaging methods have not been validated and will not be widely available for some time. The findings of this review, together with experience acquired thus far and the results of some ongoing research projects, have paved the way for RECIST 2.0 to be hopefully announced later this year.