A new study strengthens the evidence that asbestos exposure significantly increases the risk of developing esophageal cancer, raising fresh concerns about long-term occupational and environmental exposure.

For years, asbestos has been widely recognized as a primary cause of serious respiratory diseases, including lung cancer and mesothelioma. However, a new large-scale French study has revealed a strong link between asbestos exposure and esophageal cancer, demonstrating that the harmful effects of asbestos extend beyond the lungs into the digestive system.

¿Qué es exactamente el asbesto?

Asbestos is a naturally occurring fibrous mineral that was sought-after in numerous industries up until the 1980s when the Environmental Protection Agency (EPA) was successful in instituting a partial ban. The construction, shipbuilding, automotive, and textile industries preferred using asbestos due to its heat resistance, durability and widespread availability, making it a particularly inexpensive option.  

The Asbestos Cover-Up

Despite the fact that asbestos was used extensively for many years, there were well-documented cases of respiratory illnesses and other diseases along the way. For some time, manufacturers were, unfortunately, successful in the attempts to conceal the dangers of asbestos, but eventually, the evidence became too extensive to keep brushing under the rug.

Now, asbestos is known to be a dangerous carcinogen, responsible for numerous cases of lung cancer, ovarian cancer, mesotelioma, and more. It has also been tied to asthma, COPD, emphysema, and asbestosis, and this new study suggests that fibers can contribute to the development of esophageal cancer and other digestive system malignancies as well.

El estudio, published in February in BMC Public Health, followed 13,481 male workers in France who had experienced occupational exposure to asbestos. Conducted over a 10-year period from 2003 to 2013, the research team assessed asbestos exposure levels using a cumulative exposure index (CEI) measured in equivalent fiber-years per milliliter (f.y/mL).

To examine the potential link between asbestos exposure and digestive cancers specifically, researchers collected data on the incidence and mortality of various digestive cancers, including esophageal cancer. A subgroup of 4,794 men also underwent chest CT scans to determine the presence of pleural plaques, a marker of asbestos exposure, discussed in greater detail below.

Key Findings in the Study on Asbestos and Esophageal Cancer

There were several notable findings, especially with regards to the clinically significant association between asbestos exposure on the job and the later development of esophageal cancer. The team found that for every unit increase in CEI, the risk of developing esophageal cancer increased by 3% (HR 1.03, 95% CI [1.01–1.06]).

In subjects who had undergone CT scans, the presence of pleural plaques was significantly associated with esophageal cancer incidence (HR 2.80, 95% CI [1.09–7.20]). In the mortality study, higher CEI levels were linked to an increased risk of death from esophageal cancer (HR 1.03, 95% CI [1.00–1.05]).

How Asbestos May Cause Esophageal Cancer

While the direct mechanism linking asbestos to esophageal cancer is still under investigation, several hypotheses have been proposed, including:

  1. Ingestion of Asbestos Fibers: 

Workers exposed to airborne asbestos fibers may inadvertently swallow them, allowing the fibers to travel through the digestive tract and embed themselves in esophageal tissues. Inhaled or ingested through the mouth or nose, these microscopic fibers latch themselves permanently onto internal tissues where they cause inflammation and cell damage over time.

  1. Chronic Inflammation and Cellular Damage: 

Again, persistent irritation from asbestos fibers could lead to chronic inflammation, a known factor in cancer development of all kinds, including those of the digestive tract. Over time, this inflammation may trigger cellular mutations leading to malignancy.

  1. Systemic Effects of Asbestos: 

The body’s response to inhaled fibers can cause systemic inflammation, meaning that the inflammation becomes widespread throughout the body, which may indirectly increase the risk of esophageal cancer.

The above hypotheses are all interrelated with the commonality of swallowing fibers, which are indestructible and impossible to remove, leaving the body to adapt in unhealthy ways.

The Role of Pleural Plaques in Cancer Risk

Pleural plaques are calcified deposits on the lung’s lining, often resulting from extended asbestos exposure. Although they are generally considered non-cancerous, their presence in this study was associated with an increased risk of esophageal cancer. This suggests that placas pleurales may serve as a marker for high levels of asbestos exposure, indirectly pointing to a greater likelihood of asbestos-induced digestive cancers. Overall, the data was helpful in that it provided evidence of how much asbestos it might take to develop pleural plaques and the associated between these and the onset of cancer.

Implications for Occupational Health and Safety

This study reinforces the urgent need for stricter asbestos regulations and improved worker protections. Despite bans and restrictions in many countries, legacy asbestos remains present in older buildings and industries, posing ongoing risks to workers and residents. It also continues to be an issue with vintage products and imports from countries with laxer restrictions.

Preventing Asbestos Exposure

Protocols for minimizing the risk of asbestos in aging infrastructure have traditionally called for leaving the fibers intact if they are concealed behind walls, under floorboards, in cement or asphalt, or otherwise protected from entering the air. However, as buildings age and wear and tear take their toll, these barriers can deteriorate, stirring up fibers and increasing the risk of exposure. Many experts and advocates have called for a more aggressive eradication approach, but such efforts can be costly, time-consuming, and logistically complex.

In the meantime, to better protect workers from esophageal cancer and other asbestos-related illnesses, workplaces should adhere to several key guidelines. Enhanced workplace safety measures, including the use of personal protective equipment (PPE) and routine health screenings, are essential in industries with potential asbestos exposure. Medical monitoring for at-risk populations should also be prioritized, ensuring that workers with known asbestos exposure undergo regular medical examinations, including digestive health assessments, to detect early signs of esophageal and other cancers. Finally, public awareness and education efforts must be expanded to inform workers, employers, and healthcare professionals about asbestos exposure risks and encourage proactive measures to minimize health threats.

A Growing Concern: Other Digestive Cancers and Asbestos

While this study focused on esophageal cancer, it raises concerns about other digestive cancers that have also been found to be potentially linked to exposure. The fact that fibers in the digestive tract contribute to cellular damage, chronic inflammation, and mutations means that the body can become susceptible to other forms of malignancies as well, including stomach, colorectal (colon), liver, and pancreatic cancer.

While all forms of cancer can be life-threatening, these cancers are some of the deadliest. Known to be particularly aggressive, the cancers outlined in the study tend to have nonspecific symptoms or those that only present in later stages. It is not uncommon for those suffering from stomach, colon, liver or pancreatic cancer to be diagnosed when treatments are limited.

To add to this complication, there tends to be a long latency period between asbestos exposure and the onset of symptoms. Oftentimes, individuals are diagnosed with these diseases decades after initial exposure, making it difficult to identify asbestos as the cause. If there is a proven link between the two, cancer patients and their families may opt to pursue legal recourse either by way of a traditional lawsuit or trust to compensate for the medical bills that follow.

Broadening the Scope of Asbestos Research and Regulation

The findings of this study emphasize the broader health impacts of asbestos exposure beyond respiratory diseases. With a clear association between asbestos and esophageal cancer, there is an urgent need for increased research, stronger regulations, and enhanced medical monitoring for individuals at risk. As the scientific community’s understanding of asbestos-related diseases evolves, protecting workers and the general public from these long-term health threats should remain a top priority. Future studies might explore the association between cancer and asbestos exposure, now that a direct link has been discovered.