It can take anywhere from 20 to 50 years for mesothelioma to develop after asbestos exposure. The time it takes for the disease to develop is called the latency period.

From Exposure to Diagnosis

The time between asbestos exposure and a mesothelioma diagnosis is known as the latency period. There is no safe exposure level of asbestos. Any inhaled or ingested fibers, given enough time, may cause mesothelioma.

Effects and Factors of Latency Period

  • Asbestos Exposure

    It takes a long time before asbestos starts causing scarring and cell mutation that leads to mesothelioma. Generally, the length of the latency period depends on how severe a person’s asbestos exposure was.

  • Occupation

    Occupation plays a large role in how long a patient’s latency period is. Certain occupations expose workers to far greater amounts of asbestos. The longer that occupation is held, the shorter the latency period tends to be.

  • Prognosis

    Mesothelioma is one of the hardest diseases to diagnose, which is largely affected by the long latency of the disease. Patients are often given a short prognosis, so they should always seek a second opinion. Get connected with a mesothelioma specialist for a second opinion today.

Why Mesothelioma Takes So Long to Develop

Part of the reason mesothelioma is so hard to diagnose is because of the disease’s latency period. It takes decades after exposure to asbestos for the cells in the mesothelium to start mutating and becoming cancerous.

Each patient’s latency period is different. One of the key factors is the extent of asbestos exposure. The worse the exposure was, the shorter the latency period will be.

When asbestos fibers are inhaled or ingested, they become lodged in the lining of the lungs or abdomen, known as the mesothelium. These leftover asbestos fibers in the mesothelium cause scarring and inflammation over time, ultimately leading to the growth of tumors.

Most estimates find the average latency period for mesothelioma patients is approximately 40 years. One study in 1,690 mesothelioma patients found that only 4 percent were diagnosed within 20 years of their exposure.

Factors Affecting Latency Period

There are several factors that may contribute to the amount of time it takes for mesothelioma to develop. These factors coincide with the general risk factors of developing mesothelioma.

  • Duration of exposure

    The longer someone is exposed to asbestos, their risk of mesothelioma increases and their latency period is likely to decrease. More fibers enter the body the longer someone is exposed to asbestos.

  • Amount of exposure

    The frequency of exposure and the concentration of asbestos fibers both play a role in the amount of exposure. Shorter latency periods are caused by continually inhaling or ingesting large amounts of asbestos.

  • Type of asbestos

    Asbestos is a blanket term for several types of naturally occurring carcinogenic (cancer-causing) minerals. Not all types of asbestos are created equal. Crocidolite asbestos is the most deadly and may cause shorter latency periods.

A recent study reported that the median length of exposure time for people who eventually develop mesothelioma is 3.75 years.

Studies have examined other potential factors, but have shown no relationship. For example, women seem to have longer latency periods, but this is likely due to women not having the same exposure rates than it is related to their gender. Other factors, such as age and occupation, deserve more attention.

Patient Age

Everyone has cancerous cells present in their body, but these cells aren’t harmful until they start growing uncontrollably and forming tumors. The body’s immune system works fairly well to keep abnormal cells at bay, but the immune system’s efficiency starts to falter as people get older. This is why mesothelioma is most common in people over the age of 65.

It has been theorized that the rates of mesothelioma have increased over the years because people are starting to live longer on average. A recent study supporting this theory determined that as people who were exposed to asbestos get older, the risk of developing mesothelioma continues to rise. This could correlate to an increasing incidence of mesothelioma cases as well as longer average latency periods.


A person’s occupation can have a big impact on the latency period of their mesothelioma. Exposure to asbestos is more common in industrial trades, and certain trades exposed workers to higher concentrations of asbestos.

Mining, a profession already known for its correlation to respiratory conditions, has exposed workers to large amounts of asbestos in a confined space where breathing is already limited. The most devastating example of this occurred in the mining town of Libby, Montana, where workers mined asbestos-laden vermiculite. There was an unprecedented number of mesothelioma cases in this small town.

There is a synergistic effect between the concentration of asbestos and the heightened breathing rates of workers in conditions like these. This is because they are inclined to inhale large amounts of asbestos.

Shipyard workers & miners are at risk for a shorter mesothelioma latency period
Insulation workers & firefighters are at risk for a shorter mesothelioma latency period

Occupations at Risk for Shorter Mesothelioma Latency Period

Those who are exposed secondhand or environmentally have generally longer latency periods than those exposed occupationally.

Improving Diagnosis and Prognosis

Understanding the latency period of mesothelioma is important to diagnosing mesothelioma at earlier stages. Scientists and mesothelioma specialists are hoping to increase survival times by catching the disease earlier, which is part of why they are studying the potential for genetic predisposition.

Unfortunately, mesothelioma is typically only diagnosed after a patient has started experiencing symptoms. In the early stages of mesothelioma, symptoms can be minor or may not be present at all. The fact that a patient’s asbestos exposure occurred such a long time before symptoms appear makes it harder to recognize asbestos as the cause.

The latency period is considered to be one of the main culprits of the poor prognosis given to many mesothelioma patients. However, patients should understand that while the latency period is beyond their control, their prognosis is not.

Getting a second opinion can uncover a better prognosis than previously given. It is imperative to see a mesothelioma specialist experienced in diagnosing the disease to receive the best treatment possible. Getting involved in clinical trials may present patients with new opportunities for treatment and also provides financial and prognostic perks. Get connected with the latest clinical trials today.