The mesothelioma latency period is the time between asbestos exposure and symptoms that lead to a diagnosis. Compared to other types of cancer, mesothelioma latency can be as long as 20 to 50 years, which means many people get diagnosed at a later stage of cancer.
What Is a Latency Period?
A latency period is not unique to mesothelioma. Any illness with an identifiable has a latency period, which may be days to years. Latency is the time between exposure to the cause of an illness and the diagnosis.
Latency does not mean the illness is not developing. In many cases, the disease progresses during this period, and the person may still be exposed to the trigger.
This is true of mesothelioma. The cancer develops during the latency period yet shows few symptoms for years.
How Long Does Mesothelioma Take to Develop?
Mesothelioma can lie dormant for decades after asbestos exposure. The latency period for mesothelioma is between twenty and fifty years. This is long compared to many diseases, including other types of cancer.
In one study, the latency periods in a group of people with mesothelioma ranged from fourteen years to seventy-two years.[1]
This proves just how much diversity there is. In this same study, the mean latency was nearly forty-nine years. This means a longer latency is more common. Other studies have found similar results.
How Long Does Asbestosis Take to Develop?
Asbestosis, a progressive scarring in the lungs, is a much more common illness caused by asbestos exposure. It is not malignant like mesothelioma, but it can be fatal if not caught early and managed.
Like mesothelioma, most people with asbestosis have a long latency period, between 20 and 30 years. In those who experienced heavy, prolonged asbestos exposure, the latency period is typically shorter.[2]
The Emergence of Symptoms
Symptoms of mesothelioma often don’t become apparent until later in life. Someone may have experienced earlier symptoms, but not have been severe enough to warrant a visit to the doctor.
The patient or a doctor may also mistake these early symptoms for signs of more common illnesses. Typical symptoms of mesothelioma include:
- Persistent cough
- Difficulty breathing
- Chest pain
- Lumps under the skin of the chest
Once these become severe, a doctor visit may result in tests for cancer and a mesothelioma diagnosis.
What Factors Affect Latency?
The latency period of mesothelioma varies among individuals due to several factors.
Occupation
One study examined the mean latency period categorized by occupation. Occupations listed from lowest to highest latency periods were:[1]
- Insulators
- Dock workers
- Mixed occupations
- Shipyard workers
- Other people with maritime careers
Career impacts latency because it affects how extensively a person was exposed to asbestos.
Degree of Asbestos Exposure
The dose response, or extent of exposure, is another important factor affecting latency. The higher the level of exposure, the shorter the latency period is likely to be. This can be true even if the overall duration of exposure is low.
For example, workers at the World Trade Center in 2001 suffered exposure to large amounts of asbestos over a short period. This resulted in some people developing mesothelioma more quickly than usual.
Gender and Age
Sex and age also affect the latency period for mesothelioma. The latency period for women is longer.[3] This may be related to primary and secondary exposure.
Most men with mesothelioma were exposed on the job. In contrast, most women were exposed through secondhand exposure, inhaling fibers their husbands or fathers brought home on their clothing and shoes.
Age can also impact latency. The older someone is at the time of initial asbestos exposure, the shorter the latency period. This is probably due to immune system function. Typically, younger people have stronger immune systems and may hold off the negative impact of asbestos fibers longer than older people.
Type of Mesothelioma
Studies indicate a significant difference in latency period between the pleural and peritoneal types of mesothelioma. Peritoneal mesothelioma, the second most common type that develops in the abdomen, has a shorter latency period.
One study found that the median latency for pleural mesothelioma in a group of British asbestos workers was 22.9 years. The median latency for peritoneal mesothelioma in the population was just 8.2 years.[4]
Genetics
Research suggests that mesothelioma has a genetic component. Certain genetic mutations have been associated with a higher risk of developing mesothelioma after asbestos exposure.
Some studies have also found that genetic mutations could affect latency. In one case study, a patient with p53 and RAD51 genetic mutations developed mesothelioma just 8.5 years after documented asbestos exposure. This suggests that genetics impact the latency period.[5]
How Early Can Mesothelioma Be Detected?
The long latency period for mesothelioma describes the time to diagnosis, but it is not a fixed number. There is room for improvement in diagnosis that could lead to earlier detection and treatment.
Because mesothelioma is rare, few people are screened for it. Screening means testing for cancer before symptoms occur, and it’s done in people with risk factors.
No one knows exactly how early it can be detected, but experts agree that anyone with known asbestos exposure should undergo regular screenings. Imaging scans, along with blood tests for specific markers, could help people get a diagnosis even before symptoms develop.[6]
How Does the Latency Period Affect Prognosis?
The prognosis for many people diagnosed with mesothelioma is usually poor. This is partly due to the unusually long latency period of the disease.
Most people do not receive a diagnosis until decades after their asbestos exposure. In the meantime, mesothelioma develops and spreads. By the time a doctor makes a diagnosis, it is often advanced and challenging to treat. If people exposed to asbestos were diagnosed earlier, they would likely have more favorable prognoses.
The latency period is an essential factor in any disease, but it is a significant reason few people survive mesothelioma. One study recently found the latency period for mesothelioma was actually increasing. This means even fewer people have a chance of catching mesothelioma early and receiving a good prognosis.
Researchers are working on early detection methods, but it remains a struggle. If you know you have been exposed to asbestos, take proactive steps. These people should know the risks, know the symptoms, and talk to their doctors about early cancer screenings.
The long latency period puts people at high risk of dying from mesothelioma. However, it can be counteracted with vigilance and good medical care.
