Radiation therapy options for malignant pleural mesothelioma

GOECP/SEOR clinical guidelines on radiotherapy for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare tumor with poor prognosis and rising incidence. Palliative care is common in MPM as radical treatment with curative intent is often not possible due to metastasis or extensive locoregional involvement. Numerous therapeutic advances have been made in recent years, including the use of less aggressive surgical techniques associated with lower morbidity and mortality (e.g., pleurectomy/decortication), technological advancements in the field of radiotherapy (intensity-modulated radiotherapy, image-guided radiotherapy, stereotactic body radiotherapy, proton therapy), and developments in systemic therapies (chemotherapy and immunotherapy). These improvements have had as yet only a modest effect on local control and survival. Advances in the management of MPM and standardization of care are hampered by the evidence to date, limited by high heterogeneity among studies and small sample sizes. In this clinical guideline prepared by the oncological group for the study of lung cancer of the Spanish Society of Radiation Oncology, we review clinical, histologic, and therapeutic aspects of MPM, with a particular focus on all aspects relating to radiotherapy, including the current evidence base, associations with chemotherapy and surgery, treatment volumes and planning, technological advances, and reradiation.

Small bowel metastasis from pancreatic cancer in a long-term survival patient with synchronous advanced malignant pleural mesothelioma: A case report and literature review

Diffuse malignant pleural mesothelioma (MPM) is an aggressive tumor that originates from the surface of the pleura. Approximately 70% of cases are associated with chronic asbestos exposure. MPM is regarded as an incurable disease, with a median survival of ~2 years following intensive multimodality treatment. Pancreatic cancer is a malignancy also associated with a poor prognosis, with only 2% of patients surviving for 5 years. The majority of patients with pancreatic cancer are diagnosed with an advanced stage of disease and experience a poor response to therapy. The development of synchronous MPM and other types of cancer is rare. The present study describes a patient with synchronous, biphasic MPM and pancreatic adenocarcinoma, who was treated with a multimodal therapeutic approach with stereotactic body radiation therapy. Due to a suspected diagnosis of ‘acute abdomen’, an emergency small intestine resection was performed and a subsequent diagnosis of moderately-differentiated adenocarcinoma was confirmed. During a further immunohistochemical examination, pathologists determined that the small bowel metastasis descended from pancreatic cancer. The onset of bowel metastasis is an event rarely associated with MPM, and has not been previously described in the literature for cases of pancreatic cancer. Therefore, to the best of our knowledge, the present study describes the first case of intestinal metastasis from pancreatic cancer in a long-term survival patient with biphasic MPM.

Intensity-Modulated Radiation Therapy Improves the Target Coverage Over 3-D Planning While Meeting Lung Tolerance Doses for All Patients With Malignant Pleural Mesothelioma

PURPOSE

To investigate high conformality on target coverage and the ability on creating strict lung dose limitation of intensity-modulated radiation therapy in malignant pleural mesothelioma.

PATIENTS AND METHODS

Twenty-four radiation therapy plannings were evaluated and compared with dosimetric outcomes of conformal radiation therapy and intensity-modulated radiation therapy. Hemithoracal radiation therapy was performed on 12 patients with a fraction of 1.8 Gy to a total dose of 50.4 Gy. All organs at risk were contoured. Radiotherapy plannings were differed according to the technique; conformal radiation therapy was planned with conventionally combined photon-electron fields, and intensity-modulated radiation therapy was planned with 7 to 9 radiation beam angles optimized in inverse planning. Strict dose-volume constraints were applied.

RESULTS

Intensity-modulated radiation therapy was statistically superior in target coverage and dose homogeneity (intensity-modulated radiation therapy-planning target volume 95 mean 100%; 3-dimensional conformal radiation therapy-planning target volume 95 mean 71.29%, P = .0001; intensity-modulated radiation therapy-planning target volume 105 mean 11.14%; 3-dimensional conformal radiation therapy-planning target volume 105 mean 35.69%, P = .001). The dosimetric results of the remaining lung was below the limitations on intensity-modulated radiation therapy planning data (intensity-modulated radiation therapy-lung mean dose mean 7.5 [range: 5.6%-8.5%]; intensity-modulated radiation therapy-lung V5 mean 55.55% [range: 47%-59.9%]; intensity-modulated radiation therapy-lung V20 mean 4.5% [range: 0.5%-9.5%]; intensity-modulated radiation therapy-lung V13 mean 13.43% [range: 4.2%-22.9%]).

CONCLUSION

With a complex and large target volume of malignant pleural mesothelioma, intensity-modulated radiation therapy has the ability to deliver efficient tumoricidal radiation dose within the safe dose limits of the remaining lung tissue.

Radiation therapy for malignant pleural mesothelioma

Malignant pleural mesothelioma is an aggressive tumor where the ability to control the primary tumor (local control) presents a significant challenge. External beam radiation has the potential to improve local control when following established safe and effective protocols. Radiation is primarily used as adjuvant treatment after extrapleural pneumonectomy or pleurectomy/decortication and as palliative treatment in some cases. The target volume for radiotherapy of malignant pleural mesothelioma can be quite extensive and thus toxicity is its chief limitation.

Advances in the diagnosis, treatment and prognosis of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare cancer originated from pleural mesothelial cells. MPM has been associated with long-term exposure to asbestos. The prognosis of MPM is poor due to the difficulty of making diagnosis in the early stage, the rapid progression, the high invasiveness and the lack of effective treatment. Although the incidence of MPM is low in China to date, it has a tendency to increase in the coming years. The variety of clinical features may cause the delay of diagnosis and high rate of misdiagnosis. The diagnosis of MPM is based on biopsy of the pleura and immunohistochemistry. As China has become the largest country in the consumption of asbestos, it would give rise to a new surge of MPM in the future. The current treatment of MPM is multimodality therapy including surgery, radiotherapy, chemotherapy and immunotherapy. Two surgical procedures are commonly applied: extrapleural pneumonectomy (EPP) and pleurectomy/decortication (P/D). Three dimensional conformal radiotherapy is used to denote a spectrum of radiation planning and delivery techniques that rely on the 3D imaging to define the tumor. Cisplatin combined with pemetrexed (PEM) is the first-line chemotherapy for MPM. The principal targets in immunotherapy include T cells (Treg), CTLA-4 and PD-1. The diagnosis, treatment and prognosis still remain a major challenge for clinical research and will do so for years to come.

Multimodality therapy for malignant pleural mesothelioma: surgery plus chemoradiotherapy?

Malignant pleural mesothelioma, well known for its association with asbestos exposure, is an aggressive cancer of the pleura with poor prognosis if left untreated. There is no defined standard of care, but with curative surgery-based multimodality therapy, long-term survival has been documented. In addition to radiation and/or chemotherapy, multimodality therapy includes one of two operations (extrapleural pneumonectomy or radical pleurectomy/decortication) performed with the goal of resecting all gross disease. Ongoing trials are evaluating various treatment strategies involving radical resection, chemotherapy, radiation, intracavitary chemotherapy, photodynamic therapy and immunologic/biologic agents. Improvement in early diagnosis, targeted treatment and adjuvant therapy to control micrometastatic disease are needed to improve outcomes for patients with this challenging disease.

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.

Hyperthermic intraoperative pleural cisplatin chemotherapy extends interval to recurrence and survival among low-risk patients with malignant pleural mesothelioma undergoing surgical macroscopic complete resection

OBJECTIVE

Local recurrence limits long-term survival in patients with malignant pleural mesothelioma. We investigated whether hyperthermic intraoperative cisplatin chemotherapy lavage affects the interval to recurrence and overall survival among patients with favorable prognostic factors.

METHODS

Using a preoperative risk assessment algorithm we had previously developed and validated, we retrospectively identified a cohort of patients treated with cytoreductive surgery from 2001 to 2009. The patients had epithelial histologic findings on biopsy and were characterized as having a low risk of early recurrence and death (ie, tumor volume ≤ 500 cm(3) and were either men with a hemoglobin level of ≥ 13 g/dL or were women). Those patients who had received hyperthermic intraoperative cisplatin chemotherapy were compared with a comparison group of those who had not. Fisher's exact test was used to determine the balance of prognostic factors. The Kaplan-Meier method and log-rank tests were used to estimate and compare the interval to recurrence and overall survival. Cox proportional hazards regression was used for multivariate analysis.

RESULTS

The cohort criteria identified 103 patients: 72 who received hyperthermic intraoperative cisplatin chemotherapy and 31 who did not. The groups were balanced for prognostic factors, except for the use of neoadjuvant chemotherapy (more common in the comparison group). The hyperthermic intraoperative cisplatin chemotherapy group exhibited a significantly longer interval to recurrence (27.1 vs 12.8 months) and overall survival (35.3 vs 22.8 months) than the comparison group. The improved interval to recurrence and overall survival for the hyperthermic intraoperative cisplatin chemotherapy group were particularly evident among the subgroups of patients who had not received hemithoracic radiotherapy and who had pathologic stage N1 or N2 lymph node metastases.

CONCLUSIONS

A favorable outcome and minimal incremental morbidity support the incorporation of hyperthermic intraoperative cisplatin chemotherapy into multimodality treatment strategies for patients with low-risk epithelial malignant pleural mesothelioma.

[Malignant pleural mesothelioma: diagnosis and treatment]

Malignant pleural mesothelioma (MPM) is a rare and aggressive tumor issued from the mesothelial surface of the pleural space. A previous exposure to asbestos is the main risk factor of mesothelioma. Clinical signs are most of the time late and unspecific. Chest CT-scan, a key imaging procedure, usually shows a (unilateral) pleurisy associated with pleural nodular thickening. PET-scan associated with CT-scan may help to differenciate MPM from pleural benign tumors but it is not recommended for the diagnosis of MPM, as well as chest resonance magnetic imaging and blood or pleural fluid biomarkers, including soluble mesothelin still under investigation. The diagnosis of MPM is based on histology using essentially immunohistochemistry on pleural biopsies best obtained by thoracoscopy. The treatment of MPM relies mostly on chemotherapy. Surgery, pleurectomy/decortication or extrapleural pneumonectomy, is not recommended outside a clinical trial, as well as adjuvant chest radiotherapy. Prophylactic irradiation of chest scars and drains, validated by the French guidelines in 2005, is however highly discussed at the international level. Finally, numerous research studies presently assess the value of targeted therapies and biomarkers in MPM, opening new perspectives in the management of this cancer.

Cyberknife radiosurgery for focal paravertebral recurrence after radical pleurectomy/decortication in malignant pleural mesothelioma

We present a case of malignant pleural mesothelioma with focal relapse in the Azygos arch region after radical pleurectomy/decortication and adjuvant chemotherapy. Tumour recurrence was successfully treated by Cyberknife radiosurgery (70 Gy in five fractions). Patient remains disease-free at 40 months without any other treatment.

The evolution of multimodality therapy for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare neoplasm of the pleural surfaces that has been associated with asbestos exposure. MPM generally spreads locally along the ipsilateral pleura, especially at presentation, with distant metastatic disease typically seen only in the later stages of the disease course. As such, surgical resection and other local therapies have long been pursued as a primary form of treatment. Surgical options include debulking of the pleura by pleurectomy/decortication (P/D) or a more aggressive extrapleural pneumonectomy (EPP) which also involves removal of the lung, diaphragm, and involved pericardium. Even after major resection, MPM almost always recurs locally and has a poor prognosis. As such, many groups have pursued multimodality therapy, treating resectable patients with EPP, along with hemithoracic radiation to decrease the risk of local recurrence and chemotherapy to decrease the risk of distant metastatic disease. However, EPP is associated with significant morbidity and mortality, and many patients are not candidates for EPP due to underlying comorbid medical conditions. Additionally, many patients are unable to tolerate complete courses of adjuvant therapy after EPP. A large, multicenter retrospective analysis comparing EPP to P/D demonstrated better outcomes among those who underwent P/D. One challenge associated with P/D has been the delivery or radiation to the removed pleura with an intact lung. Yet, advances in radiation technique have allowed the exploration of high-dose radiation therapy after P/D. The ideal timing of chemotherapy relative to surgery and the role of intracavitary chemotherapy continue to be controversial issues. Clearly, MPM requires a multidisciplinary approach and, due to the myriad of open questions, much effort continues to focus on identifying the optimal combination of surgery, chemotherapy, and radiation.

Helical tomotherapy for resected malignant pleural mesothelioma: dosimetric evaluation and toxicity

This study evaluated adjuvant helical tomotherapy after extrapleural pneumonectomy ± neo-adjuvant chemotherapy in 24 patients with malignant pleural mesothelioma. Toxicity was judged acceptable despite 2 cases (8%) of suspected grade 5 pneumonitis. With a mean follow-up of 7 months, 5 patients had distant and 2 local and distant failure.

Photodynamic therapy for malignant pleural mesothelioma: the future of treatment?

Malignant pleural mesothelioma is a deadly incurable cancer, with a median survival of approximately 9 months. The best available chemotherapy, arguably the standard of care, only yields a 40% response rate and an 11-week extension in median survival. Surgery, the modality most likely to be associated with prolonged remission, remains investigational and must always be combined with other modalities in an effort to treat the microscopic disease that will remain even after the most aggressive operations. One such modality, photodynamic therapy, is a light-based cancer treatment that has features making it particularly well suited as a component of a surgery-based multimodal treatment plan. Utilizing intraoperative photodynamic therapy has enabled development of a less drastic surgical procedure that is also yielding some encouraging survival results. A unique aspect of photodynamic therapy is its stimulation of a tumor-directed immune response, a feature that offers promise for designing future treatments.

Mesothelioma at era of helical tomotherapy: results of two institutions in combining chemotherapy, surgery and radiotherapy

PURPOSE

There is a scarce clinical experience about adjuvant helical tomotherapy (HT) in patients affected by malignant pleural mesothelioma (MPM) even though it appears as a useful technique to treat complex volume as the pleural cavity, and seems to have better dose distribution than the "classic" intensity modulated radiotherapy (IMRT).

METHODS AND MATERIALS

Twenty-four patients received adjuvant radiotherapy (RT) by HT from August 1st, 2007 to December 1st, 2009 at Curie Institute (Paris) and René Gauducheau Cancer Center (Nantes). Thirteen patients had neoadjuvant chemotherapy. Extrapleural pleuropneumonectomy (EPP) was done in 23 patients. Median dose to PTV was 50Gy [48.7-55.9Gy] (2Gy/fraction). Acute and long term toxicities, disease free survival (DFS), overall survival (OS) and relapses are presented.

RESULTS

Average follow up after RT was 7 months. The disease was staged mostly as T2-T3, N1-N2. Nineteen patients had epithelial type histology. Most patients tolerated radiotherapy with grade 1-2 side effects: redness of the skin, light cough or dyspnea, fatigue, nausea and odynophagia, mild increase of the post-operative thoracic pain. Grade 3 pneumonitis was suspected in 2 patients. Two grade 5 pneumonitis were also suspected. Eleven patients had a follow up of more than 6 months and no long term side effects related with HT were noted. At 24 months, 51.8% of patients were free of disease. Thirty percent of patients relapsed, with 2 patients presenting local relapses. Two patients died from recurrence.

CONCLUSION

With limited follow up, HT has comparable toxicity to those observed with traditional IMRT. Higher radiation dose and good coverage results in excellent local control.

[Value of tomotherapy in malignant pleural mesothelioma: first clinical results]

INTRODUCTION

There is little clinical data about the place of helicoidal tomotherapy (HT) in the treatment of malignant pleural mesothelioma (MPM). This new form of intensity modulated radiotherapy (IMRT) has great theoretical advantages in large and complex volumes when compared to "traditional" forms of radiotherapy.

PATIENTS AND METHODS

Fourteen patients diagnosed with MPM received adjuvant radiotherapy by HT. The patients were treated at the Curie Institute and the René Gauducheau Centre, starting in August 12007. All patients had a complete initial staging, an extrapleural pneumonectomy (EPP), and a minimum follow-up of six months. The median dose prescribed to the surgical cavity was 50 Gy (48-54 Gy) in 2 Gy (1.80-2.07) fractions. High dose regions received concomitant 57 Gy (54-69 Gy) in 2.16 Gy (2.00-2.30 Gy) fractions.

RESULTS

Median follow-up was 12.6 months after ending HT. Seven patients received neoadjuvant chemotherapy (cisplatin or carboplatin, and pemetrexed). Eight patients were staged pT3 and five were staged pN1-2. HT was well tolerated. Two patients had suspected G5 radiation pneumonitis within 6 months of ending HT. Of the 12 patients who survived treatment, six relapsed (in average 5.1 months after HT): distant. Four relapses were distant; two relapses were both local and distant. Three patients died after their initial relapse. After initial diagnosis, the median survival was 18.4 months. A learning curve was observed in the optimization of the dosimetric parameters.

CONCLUSION

Helicoidal tomotherapy is a reliable, quite well tolerated, and efficient way of treating MPM patients after an EPP.