Drs. Zellos and Sugarbaker have provided a concise yet complete review of the current management of resectable diffuse malignant mesothelioma and have identified areas worthy of further investigation. Although, on occasion, surgical treatment can produce long-term cure, in general, diffuse malignant mesothelioma is a devastating disease. One only has to look at the survival curves provided by the Brigham group to understand that, of 183 patients, only 7 survived for 5 years. However, neither the number eligible for evaluation at 5 years nor the disease-free survival figures were reported.
Unfortunately, patients often present with advanced disease. The use of nonsurgical treatments in alleviating symptoms in those who are ineligible for a surgical approach (which accounts for most patients) is not discussed in this review. Suffice it to say, the results of such nonsurgical treatments have been disappointing. A few points, including the staging system controversy, the selection of patients who will benefit from surgical extirpation, and surgical results other than overall survival, are worthy of further discussion.
The revised Brigham staging system is a postsurgical pathologic staging system based on the results of attempts at complete surgical extrication by an extrapleural pneumonectomy. For good reason, the American Joint Committee on Cancer (AJCC) and International Union Against Cancer (UICC) staging systems are based on a tumor/node/metastasis (TNM) classification that can be utilized for clinical as well as final pathologic staging. In order to be useful, the Brigham system should follow these TNM guidelines, as does the International Mesothelioma Interest Group (IMIG) system.
A single staging system that can be employed for clinical as well as pathologic TNM staging would ultimately be helpful in selecting patients for surgical extirpative therapy. Indeed, it would be worthwhile to establish a consensus panel, including centers actively involved in managing this disease and various mesothelioma interest groups, to develop a single staging system approved by both the UICC and AJCC.
Selection of Patients for Aggressive Surgical Therapy
Drs. Zellos and Sugarbaker suggest that only patients with an epithelial histology and "early-stage disease" should undergo extrapleural pneumonectomy and multimodality treatment. The Brigham group offers less aggressive procedures, including pleurectomy/decortication, to patients who are not considered appropriate candidates for extrapleural pneumonectomy.
Although not stated, it is presumed that patients who have disease identified clinically to be Brigham stage III should not be offered aggressive surgery. This article does not indicate how such patients are identified. In my own approach to selection, detection of mediastinal lymph node disease or transpericardial disease prior to surgery eliminates such patients from consideration for pleuropneumonectomy. For this reason, all my patients undergo mediastinoscopy prior to consideration of surgical excision.
Results of Treatment
Although the ultimate goal of surgical treatment is long-term survival and cure, the majority of patients succumb to the disease. In most instances, disease recurrence following surgical extrication results in significant morbidity. Therefore, I believe that all surgical results should not only be described in survival terms, but also in terms of disease-free survival.
One can almost presume that once disease recurs, most patients are symptomatic. Quality-of-life assessments would be more useful, but they are much more difficult to develop. Of all patients undergoing extrapleural pneumonectomy in the Brigham experience, very few survive 5 years, and of those who do, most have extremely early-stage disease.
The results of nonsurgical management of such patients are not well documented. Long-term survival (albeit not disease-free) can occasionally be achieved with less aggressive maneuvers such as pleurodesis and chemoradiotherapy. Just as groups have reported the results with surgical treatment strategies, there should be an equal emphasis on reporting nonsurgical results, with patients subdivided into clinical stages.