Trimodality management of malignant pleural mesothelioma

The pattern of lymph node involvement influences outcome after extrapleural pneumonectomy for malignant mesothelioma

OBJECTIVE

We sought to examine the distribution and prognostic implications of nodal metastasis in patients undergoing extrapleural pneumonectomy for malignant mesothelioma in a specialist center.

METHODS

We have examined the lymphadenectomy specimens from 92 consecutive cases of malignant mesothelioma undergoing extrapleural pneumonectomy from September 1999 through February 2005 inclusive. Nodal stations (Naruke) were assigned to all nodes, and patients were staged according to the current International Union Against Cancer system. The status and number of nodes in each station were recorded, and results were correlated with the results of preoperative mediastinoscopic findings (n = 30) and survival.

RESULTS

The nodal distribution was 48 N0, 9 N1, and 35 N2. Single and multistation nodal involvement was present in 20 and 24 cases, respectively. Among the patients undergoing mediastinoscopy, N2 disease after extrapleural pneumonectomy occurred in 10 (33%). Skip N2 metastasis was present in 10 (42%) cases. Positive N2 nodes inaccessible by mediastinoscopy were present in 17 (49%) cases. N2 metastasis was associated with reduced survival (P = .02), but there was no difference between N1 and N2 cases (P = .4). The number of positive nodes correlated with survival (P = .001), although the number of involved stations and their anatomic location did not. There was no difference in survival between skip N2 cases and either other N2 or N1 cases.

CONCLUSIONS

The classical anatomic location is not as important as the scatter of nodal involvement. Every effort should be made to obtain biopsy specimens from as many stations as possible before undertaking extrapleural pneumonectomy for malignant mesothelioma.

Advances in the diagnosis, evaluation, and management of malignant pleural mesothelioma

Malignant mesothelioma is an insidious neoplasm arising from the mesothelial surfaces of the pleural and peritoneal cavities, the pericardium, or the tunica vaginalis. A total of 80% of all cases are pleural in origin. The predominant cause of malignant mesothelioma is inhalational exposure to asbestos, although evidence is increasing to support the hypothesis that simian virus-40 virus plays a role in cocarcinogenesis. Immunohistochemical markers such as calretinin, WT-1, and cytokeratin 5/6 are becoming established diagnostic markers. Preliminary data suggests that a soluble form of mesothelin could serve as a serum marker for established and early cases of mesothelioma. Positron emission tomography with 18-fluorodeoxyglucose in conjunction with computed tomograhy scanning has improved preoperative imaging and staging. Prognostic factors have been identified and verified. Negative indicators include thrombocytosis, high leukocyte counts, poor performance status, and nonepithelial histology. For the first time, there is now evidence that some treatments are increasing the quality and quantity of life for patients with mesothelioma. Chemotherapy, with the new multi-targeted antifolate drug Pemetrexed, combined with cisplatin, has shown superior survival rates in a large phase III trial when compared to cisplatin alone. High-dose intensity-modulated radiotherapy when administered after extrapleural pneumonectomy has resulted in excellent local control. Multimodality treatment programs that combine surgical cytoreduction with novel forms of radiation therapy and more effective chemotherapy combinations may offer significant increases in survival for certain subgroups of mesothelioma patients. Innovative palliative approaches have proved successful in alleviation of the significant symptoms experienced by many mesothelioma patients. Experimental treatments such as immunotherapy and gene therapy present a window of hope for all mesothelioma patients, and in the future, may be combined with 'standard therapy' in multimodality protocols. Patients with adequate performance status should be enrolled into clinical trials where possible. Over the past decade, significant advances have been made on several fronts that have improved the ability to diagnose a stage, define prognosis, and treat malignant pleural mesothelioma.

Surgical management of malignant pleural mesothelioma: a systematic review and evidence summary

An evidence summary was developed for the surgical management of adult patients with diffuse or localized malignant pleural mesothelioma. This evidence summary is based on a systematic search and review of the literature published between 1985 and February 2004. Relevant studies were identified, according to pre-determined criteria by the authors and methodologists. No randomized controlled trials comparing pleurectomy (PL) with extrapleural pneumonectomy (EPP) or comparing surgery with an alternative treatment were identified. Four comparative studies, seven non-comparative prospective studies, and 16 retrospective case series were identified that looked at PL, or EPP, or PL and EPP. Trial results were not pooled due to the heterogeneity of the treatments in the trials and the fact that no trials were randomized and none were designed to directly compare different treatments. External feedback was obtained from Ontario clinicians, and the provincial Lung Cancer Disease Site Group approved the review.

CONCLUSIONS

The role of surgery in the management of malignant pleural mesothelioma cannot be precisely defined as the lack of randomized controlled clinical trials makes it impossible to determine whether the use of EPP or PL improves survival or effectively palliates the symptoms of the disease. Future studies of the role of surgery in the treatment of mesothelioma should include evaluations of quality of life.

Preoperative assessment and therapeutic options for patients with malignant pleural mesothelioma

Prompt medical evaluation and aggressive treatment can lead to prolonged survival or successful palliation of symptoms for patients with malignant pleural mesothelioma, but the window for implementing treatment is short. Clinical recognition of the cancer is confounded by numerous factors, including long latency between exposure to asbestos and expression of the disease, nonspecific nature of the presenting symptoms, rarity of the disease, a lack of experience in clinical diagnosis, and rapidly deteriorating clinical course after diagnosis. Heightened clinical suspicion and proper patient selection through accurate staging and pathologic identification are paramount to defining and delivering therapy for this rare, lethal cancer.

Pleural mesothelioma: little evidence, still time to do trials

CONTEXT

The incidence of malignant pleural mesothelioma is increasing throughout most of the world. This cancer is uniformly fatal, and characterised by progressive breathlessness and unremitting pain in the chest wall. From the onset of symptoms, survival is from a few weeks to a few years. Desperation by patients and doctors has driven a search for effective treatments. Clinical benefits are marginal and evidence of a good quality is lamentably lacking.

STARTING POINT

David Sugarbaker is the world's leading proponent of extrapleural pneumonectomy (EPP), an operation in which all the pleura is removed with the lung, pericardium, and diaphragm. He has recently reported the complications of this radical surgery in a series of 496 operations (J Thorac Cardiovasc Surg 2004; 128: 138-46). Although EPP as part of trimodality therapy (preoperative chemotherapy and postoperative radiation) is thought to be the best that can be offered and is regarded as the standard of care for selected patients given the morbidity associated with it, evidence for benefit is needed to justify its wider use. WHERE NEXT? With the increase in the number of cases there is increasing awareness of the disease, leading to earlier diagnosis, and an expectation that something must be done. Survival is short and the treatments on offer are onerous. The only responsible approach from a scientific, compassionate, or economic view (and why not combine all three?) is to find evidence of effectiveness to avoid futile and distressing treatment when possible.

Neoadjuvant Chemotherapy Followed by Extrapleural Pneumonectomy in Malignant Pleural Mesothelioma

Purpose

To investigate neoadjuvant chemotherapy with cisplatin and gemcitabine followed by extrapleural pneumonectomy with or without radiation therapy in patients with potentially resectable malignant pleural mesothelioma (MPM).

Patients and Methods

Eligible patients had MPM with clinical stage T1-3, N0-2, M0 disease considered to be completely resectable and a WHO performance status of 0 to 2. Neoadjuvant chemotherapy consisted of three cycles of cisplatin 80 mg/m2on day 1 and gemcitabine 1,000 mg/m2on days 1, 8, and 15, given every 28 days. Surgery had to consist of a complete extrapleural pneumonectomy, including resection of pericardium and diaphragm. Postoperative radiotherapy was to be considered for all patients.

Results

Nineteen patients with MPM were included in this pilot study. According to the European Organization for Research and Treatment of Cancer prognostic score, two patients were in the good prognosis group, and 17 patients were in the poor prognosis group. The response rate to neoadjuvant chemotherapy was 32%. The major toxicity was thrombocytopenia. Extrapleural pneumonectomy was performed in 16 patients with no perioperative mortality. Major surgical complications occurred in six patients, and all were treated successfully. Thirteen patients received postoperative radiotherapy. The median survival time was 23 months. Two patients remain alive and free of disease 41 and 38 months after initiation of therapy.

Conclusion

For patients with potentially operable MPM, the availability of active and well-tolerated chemotherapy regimens, the fact that extrapleural pneumonectomy can be safely performed after neoadjuvant chemotherapy in an experienced center, and the promising results regarding survival in our pilot study warrant further investigation of the role of neoadjuvant chemotherapy in a multimodality strategy.

The effect of extent of local resection on patterns of disease progression in malignant pleural mesothelioma

BACKGROUND

We sought to determine whether or not there are differences in disease progression after radical or nonradical (debulking) surgical procedures for malignant pleural mesothelioma.

METHODS

Over a 49-month period, 132 patients with malignant pleural mesothelioma underwent surgery. Fifty-three underwent extrapleural pneumonectomy and 79 underwent nonradical procedures. Time to evidence of clinical disease progression was recorded, as was the site(s) of that disease.

RESULTS

One-hundred nineteen patients were evaluable, of which 59% (22 radical; 48 nonradical) had disease progression. Overall 30-day mortality was 8.5% (7.5% radical; 9% nonradical). The median time to overall disease progression was considerably longer after extrapleural pneumonectomy than debulking surgery (319 days vs 197 days, p = 0.019), as was the time to local disease progression (631 days vs 218 days, p = 0.0018). There was no preponderance of earlier stage disease in the radical surgery group. There was a trend toward prolonged survival in those undergoing radical surgery, but no significant difference between the groups (497 days vs 324 days, p = 0.079). In those who had extrapleural pneumonectomy, time-to-disease progression significantly decreased with N2 disease compared with N0/1 involvement (197 days vs 358 days, p = 0.02).

CONCLUSIONS

Extrapleural pneumonectomy may be preferable to debulking surgery in malignant pleural mesothelioma to delay disease progression and give greater control of local disease. Involvement of N2 nodes is associated with accelerated disease progression and is therefore a contraindication to extrapleural pneumonectomy.

The role of surgery in diagnosis and treatment of malignant pleural mesothelioma

The role of surgery in the management of mesothelioma has largely been confined to obtaining a tissue diagnosis or to effect symptom control by pleurodesis. Noninvasive, image-guided methods of obtaining pleural tissue are reducing the need for surgical biopsy, and increased use of thoracoscopy under sedation by pulmonologist is also reducing surgical involvement. However, the increasing incidence of the disease together with reports of long-term survivors has resulted in a more aggressive surgical approach toward therapy. Surgical debulking may have a role in symptom control beyond that of pleurodesis. Radical surgery, with the aim of macroscopic clearance of the tumor, may not be of prognostic benefit alone but, as part of a multimodality treatment regime, may result in long-term survivors. Adjuvant treatments with chemotherapy and radiotherapy appear to prolong survival, whereas photodynamic therapy may be detrimental. Selection criteria for radical treatment need to be refined and a radical multimodality protocol must be subjected to a randomized, controlled evaluation.

The role of imaging in the management of primary pleural malignancies

Malignant pleural mesothelioma is a rare tumour, but its incidence is increasing. Imaging is invariably involved in its diagnosis, staging, and follow-up. Although there are some characteristic radiological signs, none are pathognomonic. Computed tomography (CT) and magnetic resonance (MR) have similar local staging accuracies, but have distinct limitations; MR has marginal superiority in specific areas and should probably be offered to surgical candidates. The capabilities of multidector CT await evaluation. The role of positron emission tomography (PET), and PET-CT is undefined, but will likely have a major contribution. The challenges in imaging are matched by controversies in staging and treatment, which require future close multidisciplinary and multicentre collaboration.

Photodynamic therapy for mesothelioma

Multiple trials of traditional cancer therapies for malignant pleural mesothelioma (including surgery, radiation therapy, and chemotherapy) have not convincingly demonstrated that any one treatment is superior to supportive care alone. Although there have been reports of long-term survivors who were treated with aggressive surgery combined with radiation and aggressive multi-agent chemotherapeutic regimens, these patient populations are highly selected and results cannot be generalized to a larger population. Despite attempts to use aggressive multimodality therapies, disease recurs in most patients. Local failure in particular is a large part of the natural history of mesothelioma, especially after surgery alone. Therefore, one of the major considerations in the development of new treatments is the inclusion of aggressive local therapies. Photodynamic therapy (PDT), a local treatment modality, is being evaluated as an adjuvant therapy to surgical resection. Clinical use of PDT requires the use of a photosensitizing agent and light of a wavelength specific to the absorption characteristics of the sensitizer in the presence of oxygen. The treatment effect of PDT is superficial, mostly because of the limited depth of light absorption in tissues. Therefore, it is theoretically an ideal treatment for tissue surfaces and body cavities after surgical debulking procedures. One theoretical advantage of PDT is that it can be used to treat the lung surface after a pleurectomy; therefore, patients may be treated with a pleurectomy rather than with an extrapleural pneumonectomy. Several studies have evaluated the efficacy of PDT in the treatment of mesothelioma. Clinical studies have not proven convincingly that the use of PDT is superior to the use of other adjuvant therapies or to surgery alone. The advent of newer photosensitizers and improved laser technology has led to a renewed interest in evaluating PDT. Additional studies are necessary to determine the role of PDT in the treatment of mesothelioma.