Mesothelioma is an aggressive cancer that forms in the mesothelium — the thin lining that surrounds the lungs, abdomen, heart, and other organs. It is caused almost exclusively by exposure to asbestos, and it typically develops 20 to 50 years after that exposure. This long latency is why people exposed decades ago are being diagnosed today.
This section explains what mesothelioma is in plain language, and links to detailed guides on its symptoms, types, stages, and prognosis.
How Asbestos Causes Mesothelioma
When asbestos fibers are inhaled or swallowed, the microscopic, durable fibers can lodge in the mesothelial lining and remain there for decades. Over time they cause the chronic inflammation, scarring, and cellular damage that can lead to cancer. Because the fibers resist the body’s clearance mechanisms, even relatively limited exposure can, decades later, result in disease. There is no known safe level of asbestos exposure.
Who Is at Risk
Mesothelioma is caused by asbestos. It is one of the few cancers with a single well-established cause, which is why an occupational history carries so much diagnostic weight.
The people most often affected worked in trades that disturbed asbestos daily over years: insulators and pipe coverers, pipefitters and steamfitters, boilermakers, electricians, millwrights, sheet metal workers, carpenters, refractory bricklayers, shipyard workers and Navy veterans, power plant and refinery operators, and building maintenance staff.
It also reaches people who never worked with it. Fibres carried home on clothing exposed spouses and children who laundered them, and that route accounts for a meaningful share of cases in people with no industrial history of their own.
Latency: Why Diagnosis Comes Decades Later
The interval between first exposure and diagnosis is typically twenty to fifty years. That has three consequences worth understanding:
- Most patients are diagnosed in their sixties or later, from work done in the 1950s through the 1980s.
- Exposure that ended before a patient’s children were born can still be the cause.
- Because early symptoms mimic common conditions and nobody connects them to work half a century earlier, a majority of cases are found at an advanced stage.
The Main Types of Mesothelioma (by location)
- Pleural mesothelioma — in the lining of the lungs; the most common form (~75-80% of cases).
- Peritoneal mesothelioma — in the lining of the abdomen; the second-most common.
- Pericardial mesothelioma — in the lining around the heart; very rare (~1% of cases).
- Pericardial (heart lining) and testicular mesothelioma are rare.
Detailed Guides
- Mesothelioma Symptoms — early and advanced warning signs
- Mesothelioma Diagnosis — imaging, biopsy, and pathology
- Mesothelioma Treatment — surgery, chemo, immunotherapy, radiation, trials
- Asbestos Lung Cancer — a separate asbestos disease
- Mesothelioma Cell Types — epithelioid, sarcomatoid, and biphasic
- Mesothelioma Stages — stages 1 through 4
- Mesothelioma Life Expectancy & Prognosis
- Pleural Thickening and Pleural Plaques — non-cancerous asbestos changes
- Asbestosis — asbestos-related lung scarring
Related on AsbestosIndex
Understanding where and how the exposure happened is central to both treatment context and legal claims. See the types of asbestos, how to identify asbestos, and the product and manufacturer database.
This information is educational and is drawn from established medical sources such as the American Cancer Society and the National Cancer Institute. It is not medical advice and is not a substitute for diagnosis and treatment by a qualified physician. Always consult your own doctor about your health.