Mesothelioma is a rare cancer that is estimated to occur in approximately 2500 people in the United States every year. These NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines(R)) focus on malignant pleural mesothelioma (MPM), which is the most common type (81%). Mesothelioma can also occur in the lining of other sites, such as the peritoneum (9%), pericardium, and tunica vaginalis testis. MPM is difficult to treat, because most patients have advanced disease at presentation. Median overall survival is approximately 1 year in patients with MPM, and 5-year overall survival is about 10%; cure is rare. MPM occurs mainly in older men (median age at diagnosis, 72 years) who have been exposed to asbestos, although it occurs decades after exposure (20–40 years later).
These NCCN Guidelines(R) for Malignant Pleural Mesothelioma were first published in 2010 and have been subsequently updated every year. The Summary of the Guidelines Updates section in the algorithm briefly describes the new changes for 2018, which are described in greater detail in this revised Discussion text; recent references have been added. Additional supplementary material in the NCCN Guidelines for Malignant Pleural Mesothelioma includes the Principles of Systemic Therapy, Principles of Supportive Care, Principles of Surgery, and Principles of Radiation Therapy. These NCCN Guidelines for Malignant Pleural Mesothelioma were developed and are updated by panel members who are also on the panel for the NCCN Guidelines for Non-Small Cell Lung Cancer.
The incidence of MPM is decreasing in men in the United States, because asbestos use has decreased since the 1970s; however, the United States still has more reported cases and deaths than anywhere else in the world. The mortality burden from asbestos-related diseases in the United States did not change from 1999 to 2015.
Although asbestos is no longer mined in the United States, it is still imported. The incidence of MPM is increasing in other countries such as Russia, Western Europe, China, and India. Mortality rates from MPM are highest in the United Kingdom, Netherlands, and Australia; mortality rates are increasing in Poland, Spain, China, Japan, Argentina, Republic of Korea, and Brazil. Russia, China, Brazil, and Canada are the top producers of asbestos.
Although most mesothelioma is linked to asbestos exposure, reports suggest that ionizing radiation may also cause mesothelioma, such as in patients previously treated with mantle radiation for Hodgkin lymphoma. Data also suggest that erionite (a mineral that may be found in gravel roads) is associated with mesothelioma. Genetic factors may also play a role in MPM, with rare families carrying a germline mutation in the BRCA1 Associated Protein 1 (BAP1) gene. Smoking is not a risk factor for mesothelioma. However, patients who smoke and have been exposed to asbestos are at increased risk for lung cancer. In addition, patients who smoke should be encouraged to quit because smoking impedes treatment (eg, delays wound healing after surgery) (see the NCCN Guidelines(R) for Smoking Cessation, available at NCCN
The histologic subtypes of mesothelioma include epithelioid (most common), sarcomatoid, and biphasic (mixed) epithelioid and sarcomatoid. Patients with epithelioid histology have better outcomes than those with either mixed or sarcomatoid histologies.
Some patients who have been exposed to asbestos only have benign pleural disease, although they may have significant chest pain. Although screening for mesothelioma has been studied in patients at high risk (ie, those with asbestos exposure), these NCCN Guidelines do not recommend screening for MPM because it has not been shown to decrease mortality (see Initial Evaluation in the NCCN Guidelines for Malignant Pleural Mesothelioma). Note that data and guidelines about screening for lung cancer with low-dose CT do not apply to MPM; there are no data to suggest that screening with low-dose CT improves survival for patients with MPM.