Mesothelioma Incidence and Trends

How Common Is Mesothelioma?

Mesothelioma is not common. There were 62,550 cases of mesothelioma diagnosed from 1999 to 2018 in the United States, according to the most recent data from the Centers for Disease Control and Prevention. This amounts to approximately 3,100 new cases of mesothelioma per year, making it rarer than other cancers. Mesothelioma is becoming even less common. Mesothelioma incidence dropped to 0.7 new cases per 100,000 people in 2018, according to the CDC.

Epidemiology studies track how rates of mesothelioma vary by sex, race, age at diagnosis and occupation. This allows researchers to identify risk factors for mesothelioma, such as working in specific industries with a high risk of asbestos exposure. Recognizing risk factors helps researchers identify groups of people who are most at risk of developing mesothelioma.

According to the National Cancer Institute’s Surveillance, Epidemiology, and End Results database, known as SEER, there is a steady downward trend in the rate of new mesothelioma cases. The most recent SEER data show that there were fewer than 3,000 new mesothelioma cases per year from 2016-2019, the lowest number since 1999. 

Mesothelioma incidence is expected to continue to drop in the coming decades. Researchers estimate that asbestos-related mesothelioma will virtually disappear after 2040, leaving only mesothelioma from other causes.

Mesothelioma Incidence by Gender

Historically, mesothelioma has been diagnosed mostly in men. Although men still represent the majority of new cases, women now account for nearly one-fourth of all cases. According to SEER data covering 1975 to 2019, mesothelioma incidence among men peaked in 1992, reaching 2.6 new cases per 100,000 people. In comparison, the peak rate for women occurred in 1995 at 0.49 new cases per 100,000 people. 

The age-adjusted incidence rate for men has dropped fairly steadily since 1992, while the incidence rate for women has remained low. However, according to the CDC, the number of mesothelioma deaths among women significantly increased from 1999-2020.

Multiple research studies have stated that the incidence of asbestos-related cancers in industrialized nations has not yet peaked; they predict the number of cases will max out during the 2020s and 2030s. In the U.S., however, it is likely that the peak in mesothelioma incidence has already occurred.

A 2021 research study found that among those older than 44 years, the incidence and death rates were higher among males than females. However, among those younger than 45 years, females had higher incidence and death rates than males.

Overall, mesothelioma incidence in the U.S. has fluctuated minimally in the past few decades. The highest rates occurred from 1989 to 2002, with a rate of more than one case per 100,000 people each year in that span. In the last 10 years of data tracked by SEER, there has only been one year (2005) with an incidence above one new case per 100,000 people.

Mesothelioma Incidence by Age and Race

Mesothelioma can take 20 to 60 years to develop — this is the main reason most patients are diagnosed at age 65 or older. According to the data from the CDC, people aged 75-84 have the highest mesothelioma incidence, with 6.8 new cases per 100,000 people. Those aged 85 and older are close behind, with 6.7 new cases per 100,000 people.

Men and women under 65 are diagnosed with mesothelioma at similar rates, but men aged 65 and older are two to six times more likely to have mesothelioma than women, according to age-specific SEER data from 2013-2017. The largest difference between genders for age-specific incidence was in ages 85 and older, with men representing 18.8 cases per 100,000 and women representing 2.8 cases per 100,000.

Race also influences mesothelioma incidence. SEER data from 2015-2019 show that mesothelioma incidence among white Americans is 0.9 cases per 100,000, while the rate is 0.4 cases per 100,000 for Black Americans.

Incidence by Mesothelioma Type

Pleural mesothelioma — the most common type — made up 82% of mesothelioma cases in the U.S. from 1999-2018. Pleural mesothelioma had an incidence rate of 0.6 cases per 100,000 people in 2018, according to the CDC.

Peritoneal mesothelioma — the second-most common type — accounted for only 9.9% of mesothelioma cases in the U.S. from 1999-2018. In 2018, the incidence of peritoneal mesothelioma was 0.1 cases per 100,000, according to CDC data.

Most cases of mesothelioma are linked to asbestos inhaled into the lungs. This explains why pleural mesothelioma — involving the outer lining of the lungs — is the most common type. It is not clear how asbestos causes peritoneal, pericardial and testicular types of mesothelioma.

Mesothelioma Incidence by Location in the U.S.

Researchers have observed high rates of mesothelioma in regions and communities that relied heavily on asbestos, including places with a history of shipbuilding and industry. States with the highest incidence of mesothelioma in 2019 include:

According to data from the CDC, mesothelioma incidence among the 50 U.S. states ranged from 0.5 to 1.3 per 100,000 people. Malignant mesothelioma is primarily attributed to asbestos exposure, and most patients were first exposed to the toxic mineral while on the job. 

Additionally, geographical areas with naturally occurring asbestos deposits, such as Montana and California, have exhibited historically high rates of mesothelioma. Areas containing former asbestos mines are considered major mesothelioma hot spots.

Although asbestos use is not officially banned in the U.S., government regulations have severely restricted the toxic mineral’s use since the 1970s. As a result, researchers believe the incidence of mesothelioma may have already peaked in the U.S. Although mesothelioma cases in the U.S. appear to be on the decline, people exposed to asbestos decades ago will continue to develop this cancer in the coming years because of its lengthy latency period. 

Today, most U.S. workers are exposed to asbestos through the demolition, renovation and maintenance of homes and buildings built before the 1980s. That’s why raising awareness of the disease will help prevent future cases.

Worldwide Mesothelioma Trends

Mesothelioma incidence is declining in the U.S. but increasing worldwide. Compared to the rest of the world, mesothelioma incidence in the U.S. is near the high end of the spectrum, but not as high as many other industrialized nations. 

Occupational exposure accounts for most of the world’s exposure to asbestos. In many of the world’s industrialized countries, workplace exposure to asbestos has reached its peak and is receding. However, new cases will continue to arise because it can take decades to develop mesothelioma after asbestos exposure.

Asbestos bans in many parts of the world are expected to decrease mesothelioma incidence over time, but it may be decades before the positive effects of the bans are seen. In countries that still use asbestos, mesothelioma rates are expected to increase.