Introduction

Evidence suggests that exposure to asbestos might lead to conditions outside the respiratory system, including

• peritoneal mesothelioma
• other extrathoracic cancers
• cardiovascular conditions secondary to pulmonary fibrosis

Peritoneal Mesothelioma

Peritoneal mesothelioma is similar to pleural mesothelioma except that it arises in peritoneal membranes. Like pleural mesothelioma, this tumor is rapidly locally invasive and often rapidly fatal after it is diagnosed. It is frequently asymptomatic, though it can often be detected by abdominal palpation as an expanding "doughy" feeling.

Peritoneal mesothelioma is rare. In men, 90% of all mesotheliomas are pleural (Weill et al. 2004. In addition, the sex difference in incidence is smaller with peritoneal mesothelioma than for pleural mesothelioma (Hillerdal 1999).

The table below shows male to female incidence ratios for the two different types of mesothelioma.

Other Extrathoracic Cancers

Researchers and regulators have not been able to reach a consensus on the effects of asbestos on extrathoracic cancers. To address this concern, the National Academy of Sciences charged the Institute of Medicine (IOM) to review the state of the evidence regarding the role of asbestos in causing selected extrathoracic cancers. The results of this panel are presented below.

Nevertheless, ATSDR and the National Toxicology Program (NTP) concur that it is prudent to consider increased risk of gastrointestinal cancer a possible effect of asbestos exposure (ATSDR 2001a; American Thoracic Society 2004. Screening for colon cancer is recommended for everyone over the age of 50, but on the basis of current evidence, screening for other extrathoracic cancers in people exposed to asbestos is not currently recommended (American Thoracic Society 2004; Griffith and Maloney 2003).

Cardiovascular Conditions

Cor pulmonale occurs in many forms of far advanced lung disease when fibrosis of the lungs leads to increased resistance to blood flow through the capillary bed. This condition is most commonly seen in patients with severe parenchymal asbestosis, though it can also occur with less severe fibrotic disease, especially if chronic obstructive pulmonary disease is simultaneously present, as is often the case with asbestos workers who smoke cigarettes.

Constrictive pericarditis rarely occurs secondary to asbestos-induced severe fibrosis or calcification of the pericardium.

Progress Check