The term “latency period” refers to the time between a patient’s asbestos exposure and the development of disease. Mesothelioma, a form of cancer which attacks the tissue layer protecting and lubricating internal organs, possesses a notoriously-long latency period extending from 20 to 50 years. However, some shorter or longer latency periods have been reported. Although several asbestos-related diseases exist, including lung cancer and asbestosis, mesothelioma’s latency period remains the longest.

Victims

In general, more sustained and intense asbestos exposure results in a shorter latency period. The average age of patients diagnosed with mesothelioma lies somewhere between age 40 and 69. Due to this long latency period and advanced age of diagnosis, individuals who suffered asbestos exposure as far back as the middle of last century may only now be exhibiting symptoms of disease. For those who do develop mesothelioma before the age of 40, childhood asbestos exposure can generally be blamed. Cases of childhood mesothelioma remain rare.                 

Disease Impact

Unfortunately, mesothelioma’s long latency period contributes to its deadliness. The lengthy delay in the appearance of symptoms of this disease means diagnosis is also often delayed, significantly contributing to its poor prognosis. When recognizable symptoms of mesothelioma do finally appear, it generally means the cancer has grown to a dangerous extent. After these symptoms are correctly identified as those of mesothelioma, the cancer has had time to develop further.

Factors Influencing Latency Period

Even the type of mesothelioma can influence the length of latency period seen. According to one study, those who developed pleural mesothelioma saw an average latency period of 35 years, while those with peritoneal mesothelioma saw a significantly shorter latency period of 28 years. However, changing statistics regarding average life expectancies and asbestos use will also likely impact the latency periods of this disease.

The shorter average life expectancy of individuals in the past means those exposed to asbestos might have simply died before this exposure became an issue. As American life expectancies continue to rise, we can expect past exposure to impact older individuals with greater frequency, especially with evidence showing that mesothelioma generally strikes when we age to the point that our immune system can no longer fight off the disease. Furthermore, a significantly-reduced level of asbestos use, widespread abatement and increased awareness indicates individuals will now suffer far less intense exposure. This less intense exposure will further contribute to the climbing latency period we can expect to see.

Exceptions

The September 11, 2001 World Trade Center attack produced exceptions to the typical latency period seen after asbestos exposure. During this attack, several buildings in the downtown New York area were decimated, spewing forth huge quantities of dangerous construction materials, including asbestos. Likely due to the intensity and duration of exposure, many first responders developed mesothelioma and other asbestos-related respiratory conditions just a handful of years after this tragedy.