Clinical outcomes of stereotactic body radiation therapy for malignant pleural mesothelioma

BACKGROUND

The objective of this study is to determine the outcomes and toxicities of patients with malignant pleural mesothelioma (MPM) treated with stereotactic body radiotherapy (SBRT).

MATERIALS AND METHODS

Data were extracted from an institutional tumor registry for patients diagnosed with mesothelioma and treated with SBRT. Kaplan-Meier and Cox regression analyses were employed to determine local control (LC) and overall survival (OS).

RESULTS

Forty-four patients with 59 total treated tumors from December 2006 to April 2022 were identified. Fifty-one (86.4 %) cases had oligoprogressive disease (five sites or less). The median prescription dose delivered was 3000 cGy in 5 fractions (range: 2700-6000 cGy in 3-8 fractions). Fifty-one (86.4 %) tumors were in the pleura, 4 (6.8 %) spine, 2 (3.4 %) bone, 1 (1.7 %) brain, and 1 (1.7 %) pancreas. The median follow-up from SBRT completion for those alive at last follow-up was 28 months (range: 14-52 months). The most common toxicities were fatigue (50.8 %), nausea (22.0 %), pain flare (15.3 %), esophagitis (6.8 %), dermatitis (6.8 %), and pneumonitis (5.1 %). There were no grade ≥ 3 acute or late toxicities. There were 2 (3.4 %) local failures, one of the pleura and another of the spine. One-year LC was 92.9 % (95 % CI: 74.6-98.2 %) for all lesions and 96.3 % (95 % CI: 76.5-99.5 %) for pleural tumors. One-year LC was 90.9 % (95 % CI: 68.1-97.6 %) for epithelioid tumors and 92.1 % (95 % CI: 72.1-98.0 %) for oligoprogressive tumors. One-year OS from time of SBRT completion was 36.4 % (95 % CI: 22.6-50.3 %). On multivariable analysis, KPS was the lone significant predictor for OS (p = 0.029).

CONCLUSIONS

Our single-institutional experience on patients with MPM suggests that SBRT is safe with a low toxicity profile and potentially achieve good local control.

Tumor-Targeted Nonablative Radiation Promotes Solid Tumor CAR T-cell Therapy Efficacy

Infiltration of tumor by T cells is a prerequisite for successful immunotherapy of solid tumors. In this study, we investigate the influence of tumor-targeted radiation on chimeric antigen receptor (CAR) T-cell therapy tumor infiltration, accumulation, and efficacy in clinically relevant models of pleural mesothelioma and non-small cell lung cancers. We use a nonablative dose of tumor-targeted radiation prior to systemic administration of mesothelin-targeted CAR T cells to assess infiltration, proliferation, antitumor efficacy, and functional persistence of CAR T cells at primary and distant sites of tumor. A tumor-targeted, nonablative dose of radiation promotes early and high infiltration, proliferation, and functional persistence of CAR T cells. Tumor-targeted radiation promotes tumor-chemokine expression and chemokine-receptor expression in infiltrating T cells and results in a subpopulation of higher-intensity CAR-expressing T cells with high coexpression of chemokine receptors that further infiltrate distant sites of disease, enhancing CAR T-cell antitumor efficacy. Enhanced CAR T-cell efficacy is evident in models of both high-mesothelin-expressing mesothelioma and mixed-mesothelin-expressing lung cancer-two thoracic cancers for which radiotherapy is part of the standard of care. Our results strongly suggest that the use of tumor-targeted radiation prior to systemic administration of CAR T cells may substantially improve CAR T-cell therapy efficacy for solid tumors. Building on our observations, we describe a translational strategy of "sandwich" cell therapy for solid tumors that combines sequential metastatic site-targeted radiation and CAR T cells-a regional solution to overcome barriers to systemic delivery of CAR T cells.

Survey of malignant pleural mesothelioma treatment in Japan: Patterns of practice and clinical outcomes in tomotherapy facilities

We conducted a nationwide survey of tomotherapy for malignant pleural mesothelioma (MPM) in Japan. Fifty-six facilities were surveyed and data on 31 patients treated curatively between 2008 and 2017 were collected from 14 facilities. Twenty patients received hemithorax irradiation after extrapleural pneumonectomy (EPP) (first group). Five patients received irradiation without EPP (second group), while six received salvage radiotherapy for local recurrence (salvage group). Among the seven patients not undergoing EPP, five (four in the second group and one in the salvage group) were treated with lung sparing pleural irradiation (LSPI) and two with irradiation to visible tumors. Two-year overall survival (OS) rates in the first and second groups were 33% and 60%, respectively (median, 13 vs 30 months, P = 0.82). In the first and second groups, 2-year local control (LC) rates were 53 and 67%, respectively (P = 0.54) and 2-year progression-free survival (PFS) rates were 16% and 60%, respectively (P = 0.07). Distant metastases occurred in 15 patients in the first group and three in the second group. In the salvage group, the median OS was 18 months. Recurrence was observed in the irradiated volume in four patients. The contralateral lung dose was higher in LSPI than in hemithorax irradiation plans (mean, 11.0 ± 2.2 vs 6.1 ± 3.1 Gy, P = 0.002). Grade 3 or 5 lung toxicity was observed in two patients receiving EPP and hemithorax irradiation, but not in those undergoing LSPI. In conclusion, outcomes of EPP and hemithorax irradiation were not satisfactory, whereas LSPI appeared promising and encouraging.

Anticancer agent α-sulfoquinovosyl-acylpropanediol enhances the radiosensitivity of human malignant mesothelioma in nude mouse models

Malignant pleural mesothelioma (MPM) is a highly malignant disease that develops after asbestos exposure. Although the number of MPM cases is predicted to increase, no effective standard therapies have been established. The novel radiosensitizer α-sulfoquinovosyl-acylpropanediol (SQAP) enhances the effects of γ-radiation in human lung and prostate cancer cell lines and in animal models. In this study, we explored the radiosensitizing effect of SQAP and its mechanisms in MPM. The human MPM cell lines MSTO-211H and MESO-4 were implanted subcutaneously into the backs and thoracic cavities of immunodeficient KSN/Slc mice, then 2 mg/kg SQAP was intravenously administered with or without irradiation with a total body dose of 8 Gy. In both the orthotopic and ectopic xenograft murine models, the combination of irradiation plus SQAP delayed the implanted human MSTO-211H tumor growth. The analysis of the changes in the relative tumor volume of the MSTO-211H indicated a statistically significant difference after 8 Gy total body combined with 2 mg/kg SQAP, compared to both the untreated control (P = 0.0127) and the radiation treatment alone (P = 0.0171). After the treatment in each case, immunostaining of the harvested tumors revealed decreased cell proliferation, increased apoptosis and normalization of tumor blood vessels in the SQAP- and irradiation-treated group. Furthermore, hypoxia-inducible factor (HIF) 1 mRNA and protein expression were decreased, indicating reoxygenation in this group. In conclusion, SQAP improved hypoxic conditions in tumor tissue and may elicit a radiosensitizing effect in malignant mesothelioma models.

Disease-Related Outcomes and Toxicities of Intensity Modulated Radiation Therapy After Lung-Sparing Pleurectomy for Malignant Pleural Mesothelioma: A Systematic Review

PURPOSE

This review explores the use of intensity modulated radiation therapy (IMRT) after lung-sparing surgery in malignant pleural mesothelioma (MPM). Because severe toxicities have been documented after radiation therapy for MPM, its use remains controversial, especially as modern surgical management has shifted toward lung-sparing pleurectomy/decortication. IMRT is an advanced technique that may allow for safer radiation therapy delivery, but there remains limited data (including no summative data) to support this notion.

METHODS AND MATERIALS

We performed a systematic review evaluating the safety and efficacy of post-pleurectomy IMRT (P-IMRT). A systematic review of PubMed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted for publications of all dates that specifically reported clinical outcomes and/or toxicities of P-IMRT in patients with MPM. Ten original studies were included in this review.

RESULTS

The incidence of grade 3 pneumonitis ranged from 0% to 16%, with all but 2 studies reporting rates below 9%. Grade 4 and 5 pneumonitis were observed in less than 1.5% of cases, except in one publication that used hypofractionated radiation therapy to doses >60 Gy. Crude local failure rates ranged from 19% to 60%, median progression free survival ranged from 12 to 16 months, and median overall survival ranged from 19 to 28 months.

CONCLUSIONS

P-IMRT produces relatively few higher-grade toxicities and has reasonable disease-related outcomes, especially when delivered using conventionally fractionated regimens to doses of 45 to 54 Gy and exercising careful attention to dose constraints during treatment planning. IMRT can thus be considered in well-selected patients in whom adequate survival after pleurectomy is expected. These data also support the initiation of the phase III NRG-LU006 trial of extended pleurectomy/decortication and chemotherapy with or without IMRT.

Pattern of failure after adjuvant radiotherapy following extrapleural pneumonectomy of pleural mesothelioma in the SAKK 17/04 trial

Postoperative radiotherapy after extrapleural pneumonectomy of malignant pleural mesothelioma was investigated in the randomized phase II trial SAKK17/04. The relapse rate within the high and/or low-dose PTV without previous distant failure was 24%, the isolated in-field-relapse rate within the PTVs was 5% and the distant relapse rate outside of the PTVs was 81%. Clinical outcome was mainly determined by distant disease progression outside of the radiation field.

Malignant Pleural Mesothelioma: A Multi-Disciplinary Approach

BACKGROUND

Malignant pleural mesothelioma is a rare disease with poor prognosis. Surgery is used as a radical treatment modality but the risk of local relapse is very high. Therefore, radiation therapy is used in postoperative setting to improve local control. However, owing to elliptical shape, treating the entire pleura requires a large radiation field which increases toxicity. Precision radiation is mandatory to optimally irradiate the tumor area while sparing critical neighboring normal organs.

CASE PRESENTATION

A 43-year-old male presented with history of right sided chest pain and cough for 8 months. On further evaluation, he was diagnosed with malignant pleural mesothelioma. The disease was localized but unresectable, therefore a course of neoadjuvant chemotherapy was given. Post chemotherapy, he underwent extra pleural pneumonectomy and the tumor was grossly excised. Histopathology revealed a close resection margin with metastasis in the regional lymph nodes. The case was discussed in multidisciplinary team meeting and adjuvant radiation therapy was offered. The patient was planned with a blend of modern intensity modulated radiation therapy technique and conventional three-dimensional conformal radiation therapy technique, to keep doses of adjacent organs within tolerance limits and at the same time deliver the intended dose of radiation to the tumor site.

CONCLUSION

Malignant pleural mesothelioma is a lethal disease. Orthodox methods of radiation delivery encompass the entire involved hemi thorax and result in significant morbidity. Highly conformal radiation techniques are preferred to achieve optimal therapeutic ratio at this site. However, despite advances in radiation techniques, current treatment modalities have not significantly made an impact on survival of these patients.

A Novel Prospective Study Assessing the Combination of Photodynamic Therapy and Proton Radiation Therapy: Safety and Outcomes When Treating Malignant Pleural Mesothelioma

Malignant pleural mesothelioma remains difficult to treat, with high failure rates despite optimal therapy. We present a novel prospective trial combining proton therapy (PT) and photodynamic therapy (PDT) and the largest-ever mesothelioma PT experience (n = 10). PDT photosensitizers included porfimer sodium (2 mg·kg-1 ; 24 h drug-light interval) or 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH) (4 mg·m-2 ;48 h) with wavelengths of 630 nm to 60J·cm-2 and 665 nm to 15-45J·cm-2 , respectively. With a median age of 69 years, patients were predominantly male (90%) with epithelioid histology (100%) and stage III-IV disease (100%). PT was delivered to a median of 55.0 CGE/1.8-2.0 CGE (range 50-75 CGE) adjuvantly (n = 8) or as salvage therapy (n = 2) following extended pleurectomy/decortication (ePD)/PDT. Two-year local control was 90%, with distant and regional failure rates of 50% and 30%, respectively. All patients received chemotherapy, and four received immunotherapy. Surgical complications included atrial fibrillation (n = 3), pneumonia (n = 2), and deep vein thrombosis (n = 2). Median survival from PT completion was 19.5 months (30.3 months from diagnosis), and 1- and 2-year survival rates were 58% and 29%. No patient experienced CTCAEv4 grade ≥2 acute or late toxicity. Our prolonged survival in very advanced-stage patients compares favorably to survival for PT without PDT and photon therapy with PDT, suggesting possible spatial or systemic cooperativity and immune effect.

[Malignant pleural mesothelioma: The role of surgery]

INTRODUCTION

Malignant pleural mesothelioma (MPM) is a rare and highly aggressive disease, whose incidence is increasing. Asbestos is the primary causal agent.

STATE OF KNOWLEDGE

Knowledge about MPM has evolved. Thoracoscopy is essential for diagnosis of MPM. It allows performing pleural biopsies, to study the extent of the disease and to relieve dyspnea. The pathological diagnosis is also better codified with immunohistochemistry and with analysis by expert of Mesopath group. Curative surgical treatments are pleurectomy decortication and extended pneumonectomy in combination with chemotherapy and/or radiotherapy. Those heavy treatments improve survival in highly selected patients. For the other patients, supportive measures will be considered to reduce pain and dyspnea.

PROSPECT

Radical surgical treatment is only offered in therapeutic trials or multimodal treatment. Its place is not formally established. New therapies associated to surgical treatment are being studied.

CONCLUSIONS

Surgical management of MPM has to be operated in specialized teams where the survival benefit and quality of life is discussed case by case.

Management of Malignant Mesothelioma by Decortication and Adjunct Phototherapy

Malignant mesothelioma is a relatively rare tumor that originates in the pleural space and almost invariably results from exposure to asbestos. Between September 1989 and December 1999, 100 patients were managed with curative intent using a combination of full decortication, adjunct phototherapy after administration of hematoporphyrin derivative, and strip radiotherapy to any areas where adequate clearance was not obtained. The survival curve was compared to that of 17 matched patients treated by decortication alone. Median survival increased from 250 to 440 days in the combined treatment group.

Protocol for PIT: a phase III trial of prophylactic irradiation of tracts in patients with malignant pleural mesothelioma following invasive chest wall intervention

INTRODUCTION

Histological diagnosis of malignant mesothelioma requires an invasive procedure such as CT-guided needle biopsy, thoracoscopy, video-assisted thorascopic surgery (VATs) or thoracotomy. These invasive procedures encourage tumour cell seeding at the intervention site and patients can develop tumour nodules within the chest wall. In an effort to prevent nodules developing, it has been widespread practice across Europe to irradiate intervention sites postprocedure--a practice known as prophylactic irradiation of tracts (PIT). To date there has not been a suitably powered randomised trial to determine whether PIT is effective at reducing the risk of chest wall nodule development.

METHODS AND ANALYSIS

In this multicentre phase III randomised controlled superiority trial, 374 patients who can receive radiotherapy within 42 days of a chest wall intervention will be randomised to receive PIT or no PIT. Patients will be randomised on a 1:1 basis. Radiotherapy in the PIT arm will be 21 Gy in three fractions. Subsequent chemotherapy is given at the clinicians' discretion. A reduction in the incidence of chest wall nodules from 15% to 5% in favour of radiotherapy 6 months after randomisation would be clinically significant. All patients will be followed up for up to 2 years with monthly telephone contact and at least four outpatient visits in the first year.

ETHICS AND DISSEMINATION

PIT was approved by NRES Committee North West-Greater Manchester West (REC reference 12/NW/0249) and recruitment is currently on-going, the last patient is expected to be randomised by the end of 2015. The analysis of the primary end point, incidence of chest wall nodules 6 months after randomisation, is expected to be published in 2016 in a peer reviewed journal and results will also be presented at scientific meetings and summary results published online. A follow-up analysis is expected to be published in 2018.

TRIAL REGISTRATION NUMBER

ISRCTN04240319; NCT01604005; Pre-results.

Erratum to: Tomotherapy PET-guided dose escalation--A dosimetric feasibility study for patients with malignant pleural mesothelioma

Unfortunately, erroneous author affiliations were published in the article "Tomotherapy PET-guided dose escalation – A dosimetric feasibility study for patients with malignant pleural mesothelioma". The correct list of author affiliations reads as follows: Angelo Maggio 1, Claudia Cutaia 1, Amalia Di Dia 1, Sara Bresciani 1, Anna Miranti 1, Matteo Poli 1, Elena Delmastro 2, Elisabetta Garibaldi 2, Pietro Gabriele 2 and Michele Stasi 1. 1: Medical Physics Department, Candiolo Cancer Institute – FPO, IRCCS, Turin, Italy. 2: Radiotherapy Department, Candiolo Cancer Institute – FPO, IRCCS, Turin, Italy. We apologize for any inconveniences caused.

Prophylactic Radiotherapy to Intervention Sites in Malignant Pleural Mesothelioma--Single-institution Experience and Literature Review

AIM

To evaluate the efficacy of prophylactic radiotherapy at intervention sites in patients with malignant pleural mesothelioma (MPM).

PATIENTS AND METHODS

From 05/2010 to 12/2014, 53 patients with histologically confirmed MPM were treated in order to prevent interventional site metastases. Irradiation was carried out with 3 × 7=21 Gy with 6-18 MeV electrons.

RESULTS

The mean follow-up period was 14.4 months (range=0-37 months). At the time of the analysis, 20 patients were alive. Three patients had developed a local recurrence within the irradiated site, representing a local recurrence rate of 5.7%. Toxicity was low, with transient grade I erythema found in 20.7% of patients. No grade II or higher toxicity was observed.

CONCLUSION

Our simple and time-saving RT approach to interventional sites in patients with MPM was both effective and well-tolerated. This approach is easily integrated into general treatment concepts. Until publication of results from prospective randomized trials, prophylactic RT to intervention sites should remain standard.

Is Radiotherapy Useful for Treating Pain in Mesothelioma?: A Phase II Trial

INTRODUCTION

Radiotherapy is often used to treat pain in malignant pleural mesothelioma (MPM), although there is limited evidence to support this. The aim of this trial was to assess the role of radiotherapy for the treatment of pain in MPM.

METHODS

A multicentre, single arm phase II trial was conducted. Eligible patients fulfilled the following criteria: pathological or radiological diagnosis of MPM; pain secondary to MPM; radiotherapy indicated for pain control; and more than 18 years of age. Patients had assessments of pain and other symptoms at baseline and then received 20 Gy in five daily fractions. Key follow-up points were 5 and 12 weeks posttreatment. The primary end point measure was assessment of pain at the site of radiotherapy at 5 weeks. Secondary end points included effects on quality of life, breathlessness, fatigue, mood, toxicity, and the radiological response.

RESULTS

Forty patients were recruited from three UK oncology centers. Fourteen patients had a clinically meaningful improvement in their pain 5 weeks post radiotherapy (intention to treat), with five patients having a complete improvement. On the basis of a complete case analysis of the 30 patients assessable at week 5, 47% (confidence intervals, 28.3-65.7) of patients alive at week 5 had an improvement in their pain. There was no improvement in other key symptoms or quality of life.

CONCLUSIONS

Radiotherapy for pain control in MPM is an effective treatment in a proportion of patients. Future studies examining differing radiotherapy regimens with a view to improving response rates are warranted.

Evaluation of 4D CT acquisition methods designed to reduce artifacts

Four-dimensional computed tomography (4D CT) is used to account for respiratory motion in radiation treatment planning, but artifacts resulting from the acquisition and postprocessing limit its accuracy. We investigated the efficacy of three experimental 4D CT acquisition methods to reduce artifacts in a prospective institutional review board approved study. Eighteen thoracic patients scheduled to undergo radiation therapy received standard clinical 4D CT scans followed by each of the alternative 4D CT acquisitions: 1) data oversampling, 2) beam gating with breathing irregularities, and 3) rescanning the clinical acquisition acquired during irregular breathing. Relative values of a validated correlation-based artifact metric (CM) determined the best acquisition method per patient. Each 4D CT was processed by an extended phase sorting approach that optimizes the quantitative artifact metric (CM sorting). The clinical acquisitions were also postprocessed by phase sorting for artifact comparison of our current clinical implementation with the experimental methods. The oversampling acquisition achieved the lowest artifact presence among all acquisitions, achieving a 27% reduction from the current clinical 4D CT implementation (95% confidence interval = 34-20). The rescan method presented a significantly higher artifact presence from the clinical acquisition (37%; p < 0.002), the gating acquisition (26%; p < 0.005), and the oversampling acquisition (31%; p < 0.001), while the data lacked evidence of a significant difference between the clinical, gating, and oversampling methods. The oversampling acquisition reduced artifact presence from the current clinical 4D CT implementation to the largest degree and provided the simplest and most reproducible implementation. The rescan acquisition increased artifact presence significantly, compared to all acquisitions, and suffered from combination of data from independent scans over which large internal anatomic shifts occurred.

Protocol for the surgical and large bore procedures in malignant pleural mesothelioma and radiotherapy trial (SMART Trial): an RCT evaluating whether prophylactic radiotherapy reduces the incidence of procedure tract metastases

INTRODUCTION

Patients with malignant pleural mesothelioma (MPM) may develop painful 'procedure tract metastasis' (PTM) at the site of previous pleural interventions. Prophylactic radiotherapy has been used to minimise this complication; however, three small randomised trials have shown conflicting results regarding its effectiveness. The surgical and large bore procedures in malignant pleural mesothelioma and radiotherapy trial (SMART Trial) is a suitably powered, multicentre, randomised controlled trial, designed to evaluate the efficacy of prophylactic radiotherapy within 42 days of pleural instrumentation in preventing the development of PTM in MPM.

METHODS AND ANALYSIS

203 patients with a histocytologically proven diagnosis of MPM, who have undergone a large bore pleural intervention (thoracic surgery, large bore chest drain, indwelling pleural catheter or local anaesthetic thoracoscopy) in the previous 35 days, will be recruited from UK hospitals. Patients will be randomised (1:1) to receive immediate radiotherapy (21 Gy in 3 fractions over 3 working days within 42 days of the pleural intervention) or deferred radiotherapy (21 Gy in 3 fractions over 3 working days given if a PTM develops). Patients will be followed up for 12 months. The primary outcome measure is the rate of PTM until death or 12 months (whichever is sooner), as defined by the presence of a clinically palpable nodule of at least 1 cm diameter felt within 7 cm of the margins of the procedure site as confirmed by two assessors. Secondary outcome measures include chest pain, quality of life, analgaesic requirements, healthcare utilisation and safety (including radiotherapy toxicity).

ETHICS AND DISSEMINATION

The trial has received ethical approval from the Southampton B Research Ethics Committee (11/SC/0408). There is a Trial Steering Committee, including independent members and a patient and public representative. The trial results will be published in a peer-reviewed journal and presented at international conferences.

TRIAL REGISTRATION NUMBER

ISRCTN72767336.

Extrapleural pneumonectomy or pleurectomy/decortication for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is associated with a very poor prognosis. Unlike other solid tumors, any type of planned surgery for MPM would be cytoreductive rather than radical. There are two types of surgery for MPM. Extrapleural pneumonectomy (EPP) involves en bloc resection of the lung, pleura, pericardium, and diaphragm. Pleurectomy/decortication (P/D) is a lung-sparing surgery that removes only parietal/visceral pleura. In comparison with EPP, P/D is theoretically less radical but is associated with less perioperative mortality/morbidity and less postoperative deterioration of cardiopulmonary function. It still remains unclear which surgical technique is superior in terms of the risk/benefit ratio. In this context, selection between EPP and P/D has been a matter to debate.

Clinical characteristics, treatment and survival outcomes in malignant pleural mesothelioma: an institutional experience in Turkey

PURPOSE

To compare treatment modalities and investigate potential prognostic factors for survival in patients with malignant pleural mesothelioma (MPM).

METHODS

The present study has investigated the data of 150 patients with MPM who were examined and treated in our center from 2005 to 2012.

RESULTS

The study included 87 male (58% and 63 female (42) patients. Surgical resection (pleurectomy/decortications (P/D), and extrapleural pneumonectomy (EPP)) was performed in 32 (36.7%) patients; 87 patients (58%) received chemotherapy alone and 16 (10.7%) had surgery, chemotherapy and radiotherapy (trimodal treatment). The median progression free and overall survival (PFS and OS) for all patients were 10.6 and 14.8 months, respectively. No statistically significant difference was observed between the patients who received pemetrexed/cisplatin (N=54) and gemcitabine/cisplatin (N=28) in terms of PFS and OS (p=0.145, p=0.244, respectively). Also, no statistically significant difference was registered between operated and non operated patients (PFS and OS, p=0.416, p=0.095, respectively). There was no difference in both PFS and OS rates between patients who had P/D or EPP (p=0.87, p=0.652, respectively). Log rank analysis: Eastern Cooperative Oncology Group performance status (ECOG PS) (p=0.018), histology (p<0.001), stage (p<0.001) and leukocytosis (p=0.005) were found to be significant prognostic factors of OS. At multivariate analysis, ECOG PS (p=0.016) and stage (p<0.001) were independent prognostic factors for OS.

CONCLUSION

Median OS was approximately 1 year. ECOG PS, histological type, stage and presence of leukocytosis were prognostic factors that affected both PFS and OS. EPP or P/D surgical options did not provide difference in terms of survival. Survival rates in patients who received a combination of platinum analogues with pemetrexed or gemcitabine as front-line chemotherapy were similar.

[Malignant mesotheliomas of the tunica vaginalis testis]

Malignant mesothelioma of the tunica vaginalis is rare, and is usually not diagnosed until surgery is undertaken. We report here a case in a 62-year-old man with malignant mesothelioma tunica vaginalis testis. He was referred to our hospital with a painless swelling of the left scrotal contents. There is a thickening of mesothelia of the tunica vaginalis with left sided hydrocele by ultrasonography and computed tomography scan. The tumor was resected under the diagnosis of testicular malignant tumor. However, the pathologist reported malignant mesothelioma and positive margin. He received external beam radiation therapy at a total dose of 44 Gy. Disease progression was not apparent 2 years after treatment. To our knowledge, 26 cases of malignant mesothelioma in the perineum or intrascrotum have been reported in Japan and this case is thought to be the 27th case in Japan.

Pemetrexed plus carboplatin or cisplatin as neoadjuvant treatment of operable malignant pleural mesothelioma (MPM)

AIM

The objective of this study was the retrospective evaluation of tolerability and activity of pemetrexed with carboplatin (AC) or cisplatin (AP) as neoadjuvant chemotherapy in a consecutive series of patients with malignant pleural mesothelioma (MPM).

PATIENTS AND METHODS

Patients with operable MPM received three cycles of AC or AP followed by surgery and radiotherapy.

RESULTS

Since 2005, 51 patients have been treated with AC (27) and AP (24). We observed higher incidence of grade 3 anaemia, cumulative grade 2-3 asthenia and worsening of performance status in the AP group. Response to AC and AP were; complete: 4% vs. 0%, partial: 18% vs. 17%, stable disease: 74% vs. 79%, progressive disease: 4%; the resection rate was 81% vs. 79%.

CONCLUSION

AC and AP are active and feasible neoadjuvant regimens. Progression-free survival, response, disease control and resection rate were similar in the two treatment groups. The lower tolerability to AP treatment could impair the clinical condition of patients undergoing surgery.

Role of conservative (palliative) care-only in the management of advanced malignant pleural mesothelioma

Despite new aggressive therapeutical options for advanced malignant pleural mesothelioma (MPM), benefits to survival remain limited. Moreover, deleterious effects of high-dose chemotherapy and aggressive surgery are well-known. Outcomes of untreated patients are usually not reported, and whether a treatment can be delayed or avoided is still an open question. We discuss here two clinical cases and with conservative (palliative) management alone for advanced MPM [corrected].

Induction chemotherapy, extrapleural pneumonectomy, and adjuvant radiotherapy for malignant pleural mesothelioma: experience of Guy's and St Thomas' hospitals

PURPOSE

The treatment of malignant pleural mesothelioma (MPM) remains controversial. We present a prospective study of patients treated at our institution with neoadjuvant chemotherapy, extrapleural pneumonectomy (EPP), and radical radiotherapy.

METHODS

Patients with MPM who were eligible for EPP and multimodality therapy were included in this study. Staging was through computed tomography and positron emission tomography and computed tomography (PET/CT) scanning, video-assisted thoracoscopic surgery (VATS), and mediastinoscopy. Our protocol involved three cycles of cisplatin-based neoadjuvant chemotherapy followed by extrapleural pneumonectomy and adjuvant radiotherapy (54 Gy). All patients were followed up every 3-6 months until death.

RESULTS

From March 2004 through October 2008, 25 patients were referred for EPP following neoadjuvant chemotherapy. EPP was performed in all but three patients, who were found to have T4 disease at surgery. Surgical complications included arrhythmias (28%), bronchopleural fistulas (12 %), reoperations for bleeding (8%), acute respiratory distress syndrome (4%), pneumonia (4%), septicemia (4%), vocal cord palsy (4%), and Horner's syndrome (4%). The 30-day mortality was 4%. Adjuvant radiotherapy was administered to 81% of patients after EPP. Radiotherapy toxicities included thrombocytopenia, radiation pneumonitis, pulmonary embolus, radiation hepatitis, herpes zoster, transverse myelitis, and late constrictive pericarditis. Median survival from diagnosis was 12.8 months (95% confidence interval 7.8-17.7 months). One-year survival was 54.5%; 2-year survival was 18.2%. Disease progression occurred in 77.3% of patients. Nodal status (N0 disease versus N1-N2) or histology (epithelioid versus biphasic) had no significant impact on survival.

CONCLUSION

Despite recent advances in chemotherapy, surgery, and radiotherapy, survival rates remain low for patients with MPM completing multimodality therapy including EPP.

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.

PET-guided dose escalation tomotherapy in malignant pleural mesothelioma

PURPOSE

To test the feasibility of salvage radiotherapy using PET-guided helical tomotherapy in patients with progressive malignant pleural mesothelioma (MPM).

PATIENTS AND METHODS

A group of 12 consecutive MPM patients was treated with 56 Gy/25 fractions to the planning target volume (PTV); FDG-PET/CT simulation was always performed to include all positive lymph nodes and MPM infiltrations. Subsequently, a second group of 12 consecutive patients was treated with the same dose to the whole pleura adding a simultaneous integrated boost of 62.5 Gy to the FDG-PET/CT positive areas (BTV).

RESULTS

Good dosimetric results were obtained in both groups. No grade 3 (RTOG/EORTC) acute or late toxicities were reported in the first group, while 3 cases of grade 3 late pneumonitis were registered in the second group: the duration of symptoms was 2-10 weeks. Median overall survival was 8 months (1.2-50.5 months) and 20 months (4.3-33.8 months) from the beginning of radiotherapy, for groups I and II, respectively (p=0.19). A significant impact on local relapse from radiotherapy was seen (median time to local relapse: 8 vs 17 months; 1-year local relapse-free rate: 16% vs 81%, p=0.003).

CONCLUSIONS

The results of this pilot study support the planning of a phase III study of combined sequential chemoradiotherapy with dose escalation to BTV in patients not able to undergo resection.

Interaction of radiation and pemetrexed on a human malignant mesothelioma cell line in vitro

PURPOSE

To investigate the interaction of the cytotoxic activity of the combination of pemetrexed and radiation in a human mesothelioma cell line.

MATERIALS AND METHODS

The toxic effects of treatment with radiation and/or pemetrexed (PEM) on NCI-H28 cells were assessed by clonogenic assay. TUNEL/DAPI staining was used to measure the apoptosis index (AI). Thymidylate synthase (TS) protein expression was measured by Western blotting.

RESULTS

The D0 value of the combination treatment was lower than that for radiation, indicating its addition resulted in the synergistic effects with radiation. An increase in AI was observed with the combination compared with that observed after PEM alone. Radiation induced a time-dependent decrease in TS expression. Increased TS expression was observed after PEM, but the combination treatment decreased TS expression.

CONCLUSION

Treatment with pemetrexed in combination with radiation has a supra-additive effect, partially due to the synergistic induction of apoptosis, which may be due to TS suppression, by the irradiation enhancing the effect of pemetrexed.

Extra-pleural pneumonectomy versus no extra-pleural pneumonectomy for patients with malignant pleural mesothelioma: clinical outcomes of the Mesothelioma and Radical Surgery (MARS) randomised feasibility study

BACKGROUND

The effects of extra-pleural pneumonectomy (EPP) on survival and quality of life in patients with malignant pleural mesothelioma have, to our knowledge, not been assessed in a randomised trial. We aimed to assess the clinical outcomes of patients who were randomly assigned to EPP or no EPP in the context of trimodal therapy in the Mesothelioma and Radical Surgery (MARS) feasibility study.

METHODS

MARS was a multicentre randomised controlled trial in 12 UK hospitals. Patients aged 18 years or older who had pathologically confirmed mesothelioma and were deemed fit enough to undergo trimodal therapy were included. In a prerandomisation registration phase, all patients underwent induction platinum-based chemotherapy followed by clinical review. After further consent, patients were randomly assigned (1:1) to EPP followed by postoperative hemithorax irradiation or to no EPP. Randomisation was done centrally with computer-generated permuted blocks stratified by surgical centre. The main endpoints were feasibility of randomly assigning 50 patients in 1 year (results detailed in another report), proportion randomised who received treatment, proportion eligible (registered) who proceeded to randomisation, perioperative mortality, and quality of life. Patients and investigators were not masked to treatment allocation. This is the principal report of the MARS study; all patients have been recruited. Analyses were by intention to treat. This trial is registered, number ISRCTN95583524.

FINDINGS

Between Oct 1, 2005, and Nov 3, 2008, 112 patients were registered and 50 were subsequently randomly assigned: 24 to EPP and 26 to no EPP. The main reasons for not proceeding to randomisation were disease progression (33 patients), inoperability (five patients), and patient choice (19 patients). EPP was completed satisfactorily in 16 of 24 patients assigned to EPP; in five patients EPP was not started and in three patients it was abandoned. Two patients in the EPP group died within 30 days and a further patient died without leaving hospital. One patient in the no EPP group died perioperatively after receiving EPP off trial in a non-MARS centre. The hazard ratio [HR] for overall survival between the EPP and no EPP groups was 1·90 (95% CI 0·92-3·93; exact p=0·082), and after adjustment for sex, histological subtype, stage, and age at randomisation the HR was 2·75 (1·21-6·26; p=0·016). Median survival was 14·4 months (5·3-18·7) for the EPP group and 19·5 months (13·4 to time not yet reached) for the no EPP group. Of the 49 randomly assigned patients who consented to quality of life assessment (EPP n=23; no EPP n=26), 12 patients in the EPP group and 19 in the no EPP group completed the quality of life questionnaires. Although median quality of life scores were lower in the EPP group than the no EPP group, no significant differences between groups were reported in the quality of life analyses. There were ten serious adverse events reported in the EPP group and two in the no EPP group.

INTERPRETATION

In view of the high morbidity associated with EPP in this trial and in other non-randomised studies a larger study is not feasible. These data, although limited, suggest that radical surgery in the form of EPP within trimodal therapy offers no benefit and possibly harms patients.

FUNDING

Cancer Research UK (CRUK/04/003), the June Hancock Mesothelioma Research Fund, and Guy's and St Thomas' NHS Foundation Trust.

What is the role of radiotherapy in malignant pleural mesothelioma?

OBJECTIVE

A review of the evidence supporting the use of radiotherapy in patients with mesothelioma was performed.

METHODS

Relevant publications were searched for on Medline.

RESULTS

In a Medline search on radiotherapy and mesothelioma, 611 hits were obtained. A limited number of prospective phase II trials of radiotherapy as part of trimodality protocols for early disease and in the palliation of pain were found, along with three small randomized controlled trials of port-site prophylaxis.

CONCLUSION

No randomized data exist to support the use of radiotherapy after radical surgery, although there are a large number of publications describing its use as an integral part of therapy, including seven phase II studies. One ongoing trial is randomizing patients to radiotherapy or not after extrapleural pneumonectomy. None of these studies provided any assessment of radiotherapy independent of the other modalities investigated, nor did any formally assess intensity-modulated radiotherapy. There have been several reports of excessive toxicity with this technique, and its use should be limited to phase I studies until the basis of this toxicity is better understood. Three trials have looked at port-site prophylaxis, one supporting its use and two showing no evidence of benefit. Two studies addressed pain control prospectively, one showing definite but short-lived benefits. Implications. Radiotherapy is widely used in treating mesothelioma with little supporting evidence. More randomized trials are required to justify this use in all three common settings for its use.

Hyperthermia combined with intra-thoracic chemotherapy and radiotherapy for malignant pleural mesothelioma

BACKGROUND

Prognosis for patients with malignant pleural mesothelioma (MPM) remains poor and such patients require intensive treatment. Few studies have examined hyperthermia for MPM. The present study investigated the feasibility of hyperthermia combined with weekly chemo-radiotherapy for patients with MPM and estimated the efficacy of this regimen.

METHODS

A total of 11 patients (median patient age was 67 and all had pleural effusion) with MPM were enrolled in this study. The treatment regimen comprised of weekly thermo-radiotherapy with intra-thoracic chemotherapy 2-5 times at initiation of treatment. Hyperthermia was performed once per week for approximately 60 min. Hemithorax external radiotherapy was administered once weekly on the same day as hyperthermia and just before thermochemotherapy. Median total radiation dose was 6 Gy (range, 2-10 Gy). Chemotherapy was administered into the thoracic cavity through a tube. Chemotherapeutic agents administered were CDDP for seven patients, carboplatinum (CBDCA) for three patients and both CDDP and CBDCA for one patient. Dose of CDDP was 50 mg/body and dose of CBDCA was 200-300 mg m-2. Response rate and median survival time (MST) and palliative effect were investigated.

RESULTS

Complete response was not achieved in any of the 11 patients. Partial response was achieved in three of 11 patients (27.3%), SD in six patients (54.5%) and PD in two patients (18.2%). There was no correlational relationship between thermal parameters and response. MST was 27.1 months. Pleural fluid decreased in all patients after therapy, while all patients displayed improved performance status and could be discharged from hospital. Patients with partial response had a relatively longer survival time than SD or PD. All patients underwent the complete course of treatment and only one of 11 patients developed grade 4 thrombocytopenia.

CONCLUSION

It was therefore concluded that hyperthermia combined with intra-thoracic chemotherapy using cisplatinum or carboplatinum may be tolerable. This approach appears effective and more acceptable for patients with MPM with pleural effusion than other multi-modality therapy.

The potential of proton beam radiation therapy in lung cancer (including mesothelioma)

A Swedish group of oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy. The estimations have been based on current statistics of tumour incidence, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours and normal tissues. It is estimated that about 350 patients with lung cancer and about 20 patients with mesothelioma annually may benefit from proton beam therapy.

[Diagnosis and treatment of pleural mesothelioma]

The objective of our paper was to show the data of our treated patients with malignant pleural mesothelioma. In the Department of Thoracic Surgery of Oncology Institute at Vilnius University from 1980 till 01.06.2002, 33 patients (pts), to whom diagnosis of pleural mesothelioma was confirmed by pathologist, were treated in the Clinic. A malignant pleural mesothelioma was diagnosed in 31 pts, two pts had a non-malignant form of mesothelioma. Among patients were 19 men and 14 women. The distribution of pts according to the stage of the disease was: I stage - 3, II - 1, III - 17, IV - 10. Videothoracoscopy is the best method for diagnosing pleural mesothelioma. Radical operations were performed only in 17 cases: 6 - pulmonectomy with pleuroectomy, 1 - lobectomy, 3 - atypical segmentectomy, 4 - pleuroectomy, 4 - tumorectomy. Thoracotomy was performed in 9 cases. Insufflation of talc was performed in 6 pts. Adjuvant therapy (chemotherapy or radiotherapy) was given to 10 pts.

RESULTS

Nineteen pts died of the progression of disease. Median survival of pts was 15.7 months.

CONCLUSIONS

1. Diagnosis of malignant pleural mesothelioma is difficult and confirmation of the disease is possible only after histological examination of tumor. 2. The best results of treatment were achieved after combined treatment: surgery, after chemotherapy and radiotherapy. 3. In cases of pleural effusion of diffuse pleural mesothelioma insufflation of talc or other chemical substances into pleural cavity is recommended.

Restricted Field IMRT Dramatically Enhances IMRT Planning for Mesothelioma

PURPOSE

To improve the target coverage and normal tissue sparing of intensity-modulated radiotherapy (IMRT) for mesothelioma after extrapleural pneumonectomy.

METHODS AND MATERIALS

Thirteen plans from patients previously treated with IMRT for mesothelioma were replanned using a restricted field technique. This technique was novel in two ways. It limited the entrance beams to 200 degrees around the target and three to four beams per case had their field apertures restricted down to the level of the heart or liver to further limit the contralateral lung dose. New constraints were added that included a mean lung dose of <9.5 Gy and volume receiving >or=5 Gy of <55%.

RESULTS

In all cases, the planning target volume coverage was excellent, with an average of 97% coverage of the planning target volume by the target dose. No change was seen in the target coverage with the new technique. The heart, kidneys, and esophagus were all kept under tolerance in all cases. The average mean lung dose, volume receiving >or=20 Gy, and volume receiving >or=5 Gy with the new technique was 6.6 Gy, 3.0%, and 50.8%, respectively, compared with 13.8 Gy, 15%, and 90% with the previous technique (p < 0.0001 for all three comparisons). The maximal value for any case in the cohort was 8.0 Gy, 7.3%, and 57.5% for the mean lung dose, volume receiving >or=20 Gy, and volume receiving >or=5 Gy, respectively.

CONCLUSION

Restricted field IMRT provides an improved method to deliver IMRT to a complex target after extrapleural pneumonectomy. An upcoming Phase I trial will provide validation of these results.

Prognostic factors in the treatment of malignant pleural mesothelioma at a large tertiary referral center

INTRODUCTION

Most studies describing the natural history and prognostic factors for malignant pleural mesothelioma antedate accurate pathologic diagnosis, staging by computed tomography, and a universal staging system. We conducted a large single-institution analysis to identify prognostic factors and assess the association of resection with outcome in a contemporary patient population.

METHODS

Patients with biopsy-proven malignant pleural mesothelioma at our institution were identified and clinical data were obtained from an institutional database. Survival and prognostic factors were analyzed by the Kaplan-Meier method, log-rank test, and Cox proportional hazards analysis. A p value <0.05 was considered statistically significant.

RESULTS

From 1990 to 2005, 945 patients were identified: 755 men, 190 women; median age, 66 years (range, 26-93). Extrapleural pneumonectomy was performed in 208 (22%), pleurectomy/decortication in 176 (19%). Operative mortality was 4% (16/384). Multimodality therapy including surgery was associated with a median survival of 20.1 months. Significant predictors of overall survival included histology, gender, smoking, asbestos exposure, laterality, surgical resection by extrapleural pneumonectomy or pleurectomy/decortication, American Joint Committee on Cancer stage, and symptoms. A Cox model demonstrated a hazard ratio of 1.4 without surgical resection when controlling for histology, stage, gender, asbestos exposure, smoking history, symptoms, and laterality (p = 0.003).

CONCLUSIONS

In addition to tumor histology and pathologic stage, predictors of survival include gender, asbestos exposure, smoking, symptoms, laterality, and clinical stage. Surgical resection in a multimodality setting was associated with improved survival.

Influence of radiotherapy technique and dose on patterns of failure for mesothelioma patients after extrapleural pneumonectomy

PURPOSE

Extrapleural pneumonectomy (EPP) is an effective treatment of malignant pleural mesothelioma. We compared the outcomes after moderate-dose hemithoracic radiotherapy (MDRT) and high-dose hemithoracic RT (HDRT) after EPP for malignant pleural mesothelioma.

METHODS AND MATERIALS

Between July 1994 and April 2004, 39 patients underwent EPP and adjuvant RT at Dana-Farber Cancer Institute/Brigham and Women's Hospital. Between 1994 and 2002, MDRT, including 30 Gy to the hemithorax, 40 Gy to the mediastinum, and boosts to positive margins or nodes to 54 Gy, was given, generally with concurrent chemotherapy. In 2003, HDRT to 54 Gy with a matched photon/electron technique was given, with sequential chemotherapy.

RESULTS

A total of 39 patients underwent RT after EPP. The median age was 59 years (range, 44-77). The histologic type was epithelial in 25 patients (64%) and mixed or sarcomatoid in 14 patients (36%). Of the 39 patients, 24 underwent MDRT and 15 (39%) HDRT. The median follow-up was 23 months (range, 6-71). The median overall survival was 19 months (95% confidence interval, 14-24). The median time to distant failure (DF) and local failure (LF) was 20 months (95% confidence interval, 14-26) and 26 months (95% confidence interval, 16-36), respectively. On univariate and multivariate analyses, only a mixed histologic type was predictive of inferior DF (p <0.006) and overall survival (p <0.004). The RT technique was not predictive of LF, DF, or overall survival. The LF rate was 50% (12 of 24) after MDRT and 27% (4 of 15) after HDRT (p = NS). Four patients who had undergone HDRT were alive and without evidence of disease at the last follow-up.

CONCLUSIONS

High-dose hemithoracic RT appears to limit in-field LF compared with MDRT. However, DF remains a significant challenge, with one-half of our patients experiencing DF.

Constrictive Pericarditis After Left Extrapleural Pneumonectomy and Radiotherapy for Malignant Mesothelioma

We report the devastating complication of constrictive pericarditis after multimodality therapy including left extrapleural pneumonectomy for malignant pleural mesothelioma. The patient presented with progressive dyspnea, ascites, and peripheral edema 6 months after receiving adjuvant radiotherapy. A diagnosis of constrictive pericarditis was made late in the clinical course after exhaustive investigation to exclude primary disease recurrence. Pericardial decortication was subsequently undertaken 12 months after the initial surgery, but the patient died of multi-organ failure. Our experience, combined with a review of the available literature, leads us to advise a low level of suspicion and early operation to relieve cardiac constriction. Furthermore, these complications emphasize the importance of trials such as the Mesothelioma and Radical Surgery (MARS) study.

A randomised controlled trial of intervention site radiotherapy in malignant pleural mesothelioma

BACKGROUND AND PURPOSE

To assess the effectiveness of radiotherapy in preventing tumour seeding after chest drain or pleural biopsy in patients with malignant mesothelioma and to determine, if tract metastases appear, whether they are tender or troublesome to patients.

PATIENTS AND METHODS

Patients with a histological diagnosis of pleural mesothelioma and an invasive procedure within the preceding 21 days were stratified by age, performance status and treatment centre. Randomisation was performed between immediate drain site radiotherapy 21Gy in three fractions (XRT arm) or best supportive care (BSC) with follow-up to 12 months. Patients were asked to complete questionnaires on treatment toxicity and on symptoms from any tract metastases detected.

RESULTS

Sixty-one patients were recruited from two centres between 1998 and 2004; 56 men, 5 women, median age 70. 31 were allocated to drain site radiotherapy. Seven patients developed tract metastases associated with the drain site (four XRT arm, three BSC) and four developed metastases associated with subsequent procedures at other sites (three XRT, one BSC). Two patients each developed two tract metastases. Of the 12 metastases, nine overlay the previous drain site but three were adjacent to the site. No statistically significant difference was found in the risk of tract metastasis associated with the drain site between the arms (p=0.748).

CONCLUSIONS

Prophylactic drain site radiotherapy in malignant pleural mesothelioma does not reduce the incidence of tumour seeding by the margin indicated by previous studies.

Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests

PURPOSE

Survivin, a member of the inhibitor of apoptosis gene family, has also been shown to regulate mitosis. It binds Aurora B kinase and the inner centromere protein to form the chromosome passenger complex. Both Aurora B and survivin are overexpressed in many tumors. In this study, we examined whether irradiation affected survivin and Aurora B expression in mesothelioma cells, and how inhibition of these molecules affected radiosensitivity.

METHODS AND MATERIALS

ZM447439 and survivin antisense oligonucleotides were used to inhibit survivin and Aurora B kinase respectively. Western blot was performed to determine the expression of survivin, Aurora B, phosphorylated-histone H3 (Ser 10), and caspase cleavage. Multinucleated cells were counted using flow cytometry, and cell survival after treatment was determined using clonogenic assay.

RESULTS

At 3-Gy irradiation an increase was observed in levels of survivin and Aurora B as well as the kinase activity of Aurora B, with an increase in G2/M phase. The radiation-induced upregulation of these molecules was effectively attenuated by antisense oligonucleotides against survivin and a small-molecule inhibitor of Aurora B, ZM447439. Dual inhibition of survivin and Aurora B synergistically radiosensitized mesothelioma cells with a dose enhancement ratio of 2.55. This treatment resulted in increased formation of multinucleated cells after irradiation but did not increase levels of cleaved caspase 3.

CONCLUSION

Inhibition of survivin and Aurora B induces mitotic cell arrest in mesothelioma cells after irradiation. These two proteins may be potential therapeutic targets for the enhancement of radiotherapy in malignant pleural mesothelioma.

A Preliminary Experimental Study of Boron Neutron Capture Therapy for Malignant Tumors Spreading in Thoracic Cavity

BACKGROUND

The purpose of the present study is to verify the treatment effects of boron neutron capture therapy (BNCT) in ectopic tumors implanted in the thoracic cavity mimicking malignant pleural mesothelioma (MPM).

METHODS

The tumor model was created by implanting murine squamous cell carcinoma cells into the thoracic cavity. Mice were sorted into four groups: group I for non-treatment; group II for neutron irradiation; group III for gamma-ray irradiation; and group IV for BNCT irradiation. The antitumor effect was evaluated on the basis of the change in survival time. To assess the effects of BNCT on normal lung, non-tumor bearing mice were treated using the same method as done to the tumor-burdened mice.

RESULTS

The BNCT group had a longer survival time of 31 days (range 5 - 60), which was significantly longer than that of the non-treated control group (P = 0.011), but not significantly different from that of the neutron and gamma-ray groups (P = 0.067 and 0.094, respectively). In the BNCT and neutron groups, incidence of minimal lung fibrosis was significantly higher compared with the non-treated control group (P = 0.003 and 0.04, respectively).

CONCLUSIONS

BNCT is a potentially promising treatment for malignant tumors spreading in the thoracic cavity such as MPM.

Dose-dependent pulmonary toxicity after postoperative intensity-modulated radiotherapy for malignant pleural mesothelioma

PURPOSE

To determine the incidence of fatal pulmonary events after extrapleural pneumonectomy and hemithoracic intensity-modulated radiotherapy (IMRT) for malignant pleural mesothelioma.

METHODS AND MATERIALS

We retrospectively reviewed the records of 63 consecutive patients with malignant pleural mesothelioma who underwent extrapleural pneumonectomy and IMRT at the University of Texas M. D. Anderson Cancer Center. The endpoints studied were pulmonary-related death (PRD) and non-cancer-related death within 6 months of IMRT.

RESULTS

Of the 63 patients, 23 (37%) had died within 6 months of IMRT (10 of recurrent cancer, 6 of pulmonary causes [pneumonia in 4 and pneumonitis in 2], and 7 of other noncancer causes [pulmonary embolus in 2, sepsis after bronchopleural fistula in 1, and cause unknown but without pulmonary symptoms or recurrent disease in 4]). On univariate analysis, the factors that predicted for PRD were a lower preoperative ejection fraction (p = 0.021), absolute volume of lung spared at 10 Gy (p = 0.025), percentage of lung volume receiving >or=20 Gy (V(20); p = 0.002), and mean lung dose (p = 0.013). On multivariate analysis, only V20 was predictive of PRD (p = 0.017; odds ratio, 1.50; 95% confidence interval, 1.08-2.08) or non-cancer-related death (p = 0.033; odds ratio, 1.21; 95% confidence interval, 1.02-1.45).

CONCLUSION

The results of our study have shown that fatal pulmonary toxicities were associated with radiation to the contralateral lung. V20 was the only independent determinant for risk of PRD or non-cancer-related death. The mean V20 of the non-PRD patients was considerably lower than that accepted during standard thoracic radiotherapy, implying that the V20 should be kept as low as possible after extrapleural pneumonectomy.

A large abdominal wall mass as an initial manifestation of malignant mesothelioma

Malignant mesothelioma is relatively rare and usually presents with pleural thickening and effusion at onset. In this report, we describe a 67-year-old male patient whose initial manifestation of mesothelioma was a large mass in the left flank. Mesothelioma was diagnosed from needle biopsy specimens, and, after radiotherapy, the tumor did not recur in this area. However, pleural effusion developed, which was controlled by pleurodesis, and tumors appeared around the descending aorta. Despite further radiotherapy, the patient died of cardiac tamponade due to tumor invasion 38 months after the initial diagnosis. To the best of our knowledge, this is the first description of malignant mesothelioma presenting via initial invasion of the abdominal wall without changes in the thoracic space.