Amount of Asbestos Exposure and Mesothelioma Survival

Many clinical researchers have asked the question: “Does the amount of asbestos exposure affect prognosis?” But every researcher comes to a slightly different conclusion.

Many have looked at this question. But few can agree on the answer. Recently there were two articles in the Journal of Thoracic Oncology that proposed two opposite endings on this topic.

One said that “the amount of asbestos in the lungs may directly correlate with shorter survival in patients with mesothelioma.” And the other said, “the amount of asbestos in the lungs does not influence survival.”

A new article in the International Association for the Study of Lung Cancer compares notes from all the different studies.

Dr. Michele Carbone from the University of Hawaii Cancer Center says, “Maybe exposure to a certain type of fibers or to a higher number of asbestos fibers may…affect prognosis.”

Confirming Asbestos Fiber Exposure  

Mesothelioma is caused by exposure to asbestos. Asbestos is a commercial and legal name for six mineral fibers. These six fiber types were used by different industries in different ways. This exposed millions of people worldwide to the risk of mesothelioma.

Many mineral fibers can potentially cause cancer. But asbestos fibers are the only ones regulated. The use of asbestos has now been strictly reduced, regulated or prohibited. Mostly, this happened in the 80s and 90s.

Clinical imaging is helpful to identify asbestos exposure. Asbestos is inhaled. So, an analysis of the lungs is considered the most reliable test to measure exposure. This is called lung content analyses.

You can also identify the types of asbestos fibers using this method. But different fibers degrade faster than others inside the human body. So it can be difficult to be sure that you have identified all the possible asbestos fibers.

Three Factors that Lead to Different Opinions

Let’s return to the question: “Can the amount of asbestos present in the lungs influence tumor prognosis?” There were two papers recently published. Both reached a different conclusion. Similarly, there are even older studies that also reported conflicting results.

There were three factors that were not reported in these studies. These three factors ultimately help to answer the question.

One factor to consider is the clinical setting of the patients before their death. Patients in each study were from different hospitals. And their clinical tests, images, and lung biopsies were also provided by different hospitals.

A second factor is that no data was provided about the treatment plan. A combination of cisplatin and pemetrexed is the most common mesothelioma treatment. The addition of other drugs, surgery, and radiation can add an average survival benefit of 2 to 3 months. But the type of treatment provided to mesothelioma patients was not considered in these papers.

A third factor is the option of immune-based treatments. This was also not included in the articles that were looking at the importance of the amount of asbestos exposure. Immunotherapy may benefit some patients with mesothelioma.

Finding the Answer

Two teams of scientists tried to answer the same question. But both got different and conflicting answers. This could be because they did not look deeper into the clinical setting or the treatment strategies.

Another factor that was not considered is the type of asbestos fiber. It is possible that exposure to a certain type of asbestos fiber leads to a worse prognosis. But there is yet no clinical evidence available to support this.

The scientific evidence is uncertain whether the amount of asbestos exposure influences mesothelioma prognosis. The answer is probably “it depends” on several different factors. We look forward to a new clinical trial that may hold the answer.

Source:

Yang, Haining, Giovanni Gaudino, Fabrizio Bardelli, and Michele Carbone. “Does the Amount of Asbestos Exposure Influence Prognosis?.” Journal of Thoracic Oncology 17, no. 8 (2022): 949-952. https://www.jto.org/article/S1556-0864(22)00298-2/fulltext