Expert opinions of the first italian consensus conference on the management of malignant pleural mesothelioma

Treatment patterns among patients with malignant pleural mesothelioma: An Italian, population-based nationwide study

Background

Malignant pleural mesothelioma (MPM) is a rare cancer with a poor prognosis. Centralization of rare cancer in dedicated centers is recommended to ensure expertise, multidisciplinarity and access to innovation. In Italy, expert centers for MPM have not been identified in all regions. We aimed to describe the treatment patterns among MPM patients across different Italian regions and to identify factors associated with the treatment patterns across the regions.

Methods

We performed an observational study on a random sample of 2026 MPM patients diagnosed in 2003–2008. We included 26 population‐based registries covering 70% of the Italian population. To identify factors associated with treatment patterns, across the different regions, we fitted a multinomial logistic regression model adjusted by age, sex, stage, histology and hospital with thoracic surgical department.

Results

MPM patients mostly received chemotherapy alone (41%) or no cancer‐directed therapy (36%) especially the older patients. The first course of treatment for MPM patients differed across regions. Patients from Piedmont, Liguria and Campania were more likely to receive no cancer‐directed therapy; those living in Tuscany and Sicily were more likely to get surgery; patients from Marche and Lazio were more likely to receive chemotherapy. These differences were not explained by age, sex, stage, histology and availability of a thoracic surgery department.

Conclusions

There is limited expertise available and lack of a network able to maximize the expertise available may contribute to explaining the results of our study. Our findings support the need to ensure the appropriate care of all MPM patients in reorganizing the health care services.

Key points

A review of the cohorts with environmental and occupational mineral fiber exposure

The aim of the study was to examine factors associated with Malignant Mesothelioma (MM) incidence rate of the groups with occupational asbestos and environmental asbestos or erionite exposure in rural area. In this ecological study, a total of 21 cohort datasets (8 environmental and 13 occupational) were evaluated. Data were analyzed using a multiple linear regression analysis model. In environmental cohorts, the risk of MM incidence was higher in women and people exposed to erionite. In this cohort, the incidence rate of MM increased as the median exposure time increased, while the incidence decreased as the median cumulative exposure dose increased. In occupational cohorts, the incidence rate of MM was positively correlated with the median cumulative exposure dose. The risk of mesothelioma was lower in those exposed to tremolite than others. Environmental asbestos exposure is as important as occupational exposure to develop MM, and it has its own unique exposure features on the risk of MM.

Effects of Combined Therapies on the Survival of Pleural Mesothelioma Patients Treated in Brescia, 1982–2006

Aims and background

During the 1990's, the traditional unimodal treatments (surgery, radiotherapy, chemotherapy, immunotherapy) for malignant pleural mesothelioma started to be combined in bimodal or multimodal strategies. However, recent population-based analyses of the survival of patients with malignant pleural mesothelioma indicate that even these treatments have not led to significant improvements in prognosis, which remains very poor. The present study assessed the survival of patients given combined treatments and multimodal therapies in a specialized hospital department.

Methods

The study population comprised 530 patients diagnosed with malignant pleural mesothelioma from 1982 to 2006: 343 of them were residents in the province of Brescia (Lombardy, Northern Italy) and 187 were residents outside the province, with a follow-up to 31 December 2009. Kaplan-Meier survival analyses and Cox proportional risks model were used to test sex, age at diagnosis, histological type and treatments, as prognostic factors.

Results

The estimated median survival for the whole group of patients was 317 days (257 for residents and 398 for non-residents), and respectively 310 and 340 days in the groups diagnosed in the periods 1982–2000 and 2001–2006. Multivariate analysis confirmed that the prognosis was better for younger patients and cases of epithelioid type malignant pleural mesothelioma, whereas for patients receiving any single treatment the prognosis was not significantly better than for those given palliative care alone. However, patients receiving combined treatments or the multimodality approach had significantly longer median survival and the relative risk of death was respectively 0.57 and 0.61 compared to untreated patients (or those only given symptomatic therapy).

Conclusions

This is the first study in Italy to assess the effectiveness of different treatment approaches in a significant number of patients treated in one hospital. Further studies are needed to confirm the improvement in prognosis – even if modest – on larger numbers of patients and taking into account the different stages of the disease.

Proton Therapy for Malignant Pleural Mesothelioma: A Three Case Series Describing the Clinical and Dosimetric Advantages of Proton-Based Therapy

Malignant pleural mesothelioma (MPM) is a malignancy of the pleural cavity that typically presents at an advanced stage. Due to its large, circumferential clinical target volume (CTV) and proximity to major structures, including the heart and contralateral lung, delivering hemithoracic intensity-modulated radiotherapy (IMRT) with photon therapy to achieve loco-regional control following macroscopic complete resection is challenging. Intensity-modulated proton therapy (IMPT) has been shown to be a method for achieving higher therapeutic doses while limiting exposure to organs at risk (OARs), but patient outcomes after treatment have yet to be reported. We present three patients who received IMPT to 54 Gy after extrapleural pneumonectomy (EPP), with two patients receiving boosts to 66 and 60 Gy. All three tolerated treatment well and received doses to OARs markedly lower than those seen in comparison volumetric-modulated arc therapy (VMAT) IMRT photon plans. Radiation pneumonitis, a highly morbid and potentially fatal toxicity in patients receiving thoracic radiotherapy, was not observed even with boost treatments. In practice, IMPT appears to match dosimetric predictions as a feasible and safer alternative to photon IMRT-based radiotherapy. 

Pathology reporting of malignant pleural mesothelioma first diagnosis: A population-based approach

Accurate pathologic diagnosis and reporting in malignant pleural mesothelioma are essential for clinical care, and cancer registration. Practical guidelines for pathologists are provided in publications and textbooks but it is unclear how these recommendations are applied in routine practice. We investigated the characteristics of pathology reports, and the extent to which they meet guideline standards. We reviewed 819 pathology reports relating to a first diagnosis of malignant pleural mesothelioma. Data sources were a regional section of the Italian network of the Mesothelioma Registry (2001-2014) and a pathology archive (1990-2000). We evaluated tumor characteristics, the diagnosis field including terminology and immunohistochemistry (IHC) workup, and report completeness (the proportion of items recorded). We investigated also two IHC panels identified by the most used markers in current practical guidelines, one best suited for epithelioid mesotheliomas (combinations of at least 2 positive and at least 2 negative mesothelioma markers) and the other best suited for sarcomatoid mesotheliomas (positive mesothelioma markers plus cytokeratins). Reports (753 histology, 66 cytology, IHC-confirmed 86%) were 74% complete and always narrative. Missing data were related to clinical history (76%), tumor laterality (61%), specimen size (38%), and histological subtype (23%). The proportion of cases with IHC was higher for epithelioid (90%) than sarcomatoid mesothelioma (87%). Compliance to IHC recommendations was higher for epithelioid (59%) than sarcomatoid mesothelioma (11%). The mean number of stains was significantly higher for sarcomatoid than epithelioid mesothelioma (p<0.000; Kruskal-Wallis test). Our findings show that although guidelines are designed to improve actual reporting practices, there is ample room for improvement in their application to standardize the diagnosis of mesothelioma. Synoptic pathology reporting needs to be implemented to better utilize pathology information.

The Third Italian Consensus Conference for Malignant Pleural Mesothelioma: State of the art and recommendations

Malignant Pleural Mesothelioma (MPM) remains a relevant public health issue, and asbestos exposure is the most relevant risk factor. The incidence has considerably and constantly increased over the past two decades in the industrialized countries and is expected to peak in 2020-2025. In Italy, a standardized-rate incidence in 2011 among men was 3.5 and 1.25 per 100,000 in men and women, respectively, and wide differences are noted among different geographic areas. The disease remains challenging in terms of diagnosis, staging and treatment and an optimal strategy has not yet been clearly defined. The Third Italian Multidisciplinary Consensus Conference on Malignant Pleural Mesothelioma was held in Bari (Italy) in January 30-31, 2015. This Consensus has provided updated recommendations on the MPM management for health institutions, clinicians and patients.

Role of new radiation techniques in the treatment of pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive neoplasm arising from the surface serosal cells of the pleural cavity. Surgery remains the main therapeutic standard in the treatment of MPM with the goal of complete gross cytoreduction of the tumor. Because MPM is a diffuse disease affecting the entire mesothelial lining of the hemithorax, surgery alone can rarely achieve adequate tumor-free resection margins. The surgical choices are pleurectomy/decortication (P/D) or extrapleural pneumonectomy (EPP). Radiotherapy (RT) is usually applied postoperatively with the aim to improve local control. However, the efficacy of RT is limited by the large volume of the target to be irradiated (tumor and pleural cavity) and the radiosensitivity of the nearby organs (heart, liver, lung, spinal cord, and esophagus). These factors have historically limited the effective radiation doses that can be given to the patient. There is no role for radical RT alone, but the role of RT as part of multimodality therapy is discussed. After EPP adjuvant RT to the entire hemithorax can reduce the recurrence rate and is well tolerated if strict limits to the dose to contralateral lung are applied: the V20 and V5 (the percent volume of the lung receiving more than 20Gy and 5Gy of radiation) correlate with increased lung toxicity. The use of modern sophisticated techniques allows good target coverage, more conformal high dose delivery, and clinically relevant normal tissue sparing.

Adjuvant intensity-modulated proton therapy in malignant pleural mesothelioma. A comparison with intensity-modulated radiotherapy and a spot size variation assessment

PURPOSE

Intensity-modulated radiation therapy (IMRT) is the state-of-the-art treatment for patients with malignant pleural mesothelioma (MPM). The goal of this work was to assess whether intensity-modulated proton therapy (IMPT) could further improve the dosimetric results allowed by IMRT.

PATIENTS AND METHODS

We re-planned 7 MPM cases using both photons and protons, by carrying out IMRT and IMPT plans. For both techniques, conventional dose comparisons and normal tissue complication probability (NTCP) analysis were performed. In 3 cases, additional IMPT plans were generated with different beam dimensions.

RESULTS

IMPT allowed a slight improvement in target coverage and clear advantages in dose conformity (p < 0.001) and dose homogeneity (p = 0.01). Better organ at risk (OAR) sparing was obtained with IMPT, in particular for the liver (D(mean) reduction of 9.5 Gy, p = 0.001) and ipsilateral kidney (V(20) reduction of 58%, p = 0.001), together with a very large reduction of mean dose for the contralateral lung (0.2 Gy vs 6.1 Gy, p = 0.0001). NTCP values for the liver showed a systematic superiority of IMPT with respect to IMRT for both the esophagus (average NTCP 14% vs. 30.5%) and the ipsilateral kidney (p = 0.001). Concerning plans obtained with different spot dimensions, a slight loss of target coverage was observed along with sigma increase, while maintaining OAR irradiation always under planning constraints.

CONCLUSION

Results suggest that IMPT allows better OAR sparing with respect to IMRT, mainly for the liver, ipsilateral kidney, and contralateral lung. The use of a spot dimension larger than 3 × 3 mm (up to 9 × 9 mm) does not compromise dosimetric results and allows a shorter delivery time.

Adjuvant radiotherapy after extrapleural pneumonectomy for mesothelioma. Prospective analysis of a multi-institutional series

BACKGROUND AND PURPOSE

To evaluate survival, locoregional control and toxicity in a series of 56 mesothelioma patients treated from May 2005 to May 2010 with post-operative radiotherapy after extrapleural pneumonectomy (EPP) in three Italian Institutions (Brescia, Florence, and Modena).

MATERIAL AND METHODS

Fifty-six patients treated with adjuvant radiotherapy (RT) after EPP were analyzed. Four patients were treated with 3DCRT, 50 with IMRT and two with helical tomotherapy. Forty-five to 50 Gy in 25 fractions were given to the affected hemithorax and to ipsilateral mediastinum, with a simultaneous integrated boost to the sites of microscopically involved margins up to 60 Gy in 20/56 cases.

RESULTS

Three year locoregional control (LRC), distant metastasis free (DMF), disease free (DF), disease specific (DSS) and overall survival (OS) rates are 90%, 66%, 57%, 62%, and 60%, respectively.

CONCLUSION

Postoperative RT with modern techniques is an effective method to obtain excellent local control and cure rates in mesothelioma patients submitted to EPP.