Detection of Mesothioloma Remains a Conundrum

Abstract

Malignant pleural mesothelioma remains a deadly cancer. The frustrating aspect, as with every cancer of the thorax, is that we understand the population at risk, but collectively we have yet to identify adequate markers for the risk of development of the disease. Recently there have been exciting developments of circulating markers that may prove useful in monitoring exposed populations, but application has not yet universally occurred (1–3). The article presented in this issue of the Journal by Pairon and colleagues (4) delivers a fascinating perspective to this conundrum. The standard belief has been that pleural plaques are not a signal of risk of mesothelioma. Pairon et al. present for the first time solid and useful evidence that the presence of pleural plaques can be an accurate indicator of mesothelioma risk. It needs to be understood that the plaques alone have not been proven to be premalignant lesions. For example, plaques are not shown to be positron emission tomography computed tomography avid and have largely not been useful as a good radiologic marker for a history of asbestos exposure. Pairon et al. (4) accessed a unique French population of the Asbestos Past Exposure survey (APEXS). Populations such as these have proven very useful for mesothelioma researchers and clinicians because it is well known at this time that asbestos exposure remains the major described risk factor for mesothelioma. As noted by Pairon et al., the utility, as well as methods, of screening for the exposed population remains controversial. As noted above, it remains very frustrating to clinicians that, as with the population at risk for lung cancer after tobacco exposure, the group that will be at risk for development of mesothelioma is all too clear. Without much doubt, the most uniformly characterized group of asbestos-exposed individuals are the workers and citizens that comprise the Wittenoom cohort that has been admirably characterized and monitored by Musk and colleagues from the University of Western Australia (5). Wittenoom was both a workplace and the adjacent city where asbestos was heavily mined and residentially used for 40 years. The mesothelioma rate among exposed workers in the asbestos mining operation appears to be 4.7% according to the data from the Perth research team. Although this rate continues to be unacceptably high for this fatal cancer, it is heartening to know that most of the highly exposed population of asbestos workers and local occupants did not develop mesothelioma. Indeed, Musk and colleagues continue to identify and explore preventive strategies for populations at risk for fatal asbestos-related disease, and we may all hope that patients with plaques will be included in future studies (6). Going forward, if clinicians identify patients at risk for mesothelioma, either through circulating markers or by the identification of computed tomography–based plaques, it will be an advance in the monitoring of the population at risk for mesothelioma. The work by Pairon and colleagues should prove a useful advance in this regard. r eferences