Mesothelioma: staging and emerging treatment options

Proper staging, early detection and accurate diagnosis all play a key role in successful treatment for cancer patients. This holds especially true for those facing rare cancers. Malignant mesothelioma is a rare and aggressive environmental cancer caused by exposure to asbestos. Mesothelioma is known for being difficult to diagnose and equally difficult to treat.

Concurrent with other rare cancers, low incident rates and unique ways of presenting means that the treatment options for mesothelioma vary greatly; depending on the type and stage of diagnosis and carries more weight while planning a course of treatment than more commonly treated cancers.

Upon diagnosis, patients are typically given a prognosis of only 12–21 months and predominantly left with aggressive treatment options [1]. With such a limited amount of time, early detection becomes vital and appropriately staging patients can mean the difference between taking action or having no recourse for treatment. For patients who are able to seek curative treatment, the best-case survival revolves around the ability to explore all treatment options available, from surgery all the way through to emerging last resort options such as immunotherapy and other emerging treatments.

A multimodal approach

Mesothelioma develops slowly after exposure to asbestos, taking between 10–50 years to start presenting symptoms. In addition to the slow impact of exposure, as the asbestos fibers irritate the linings of organs over many years, the initial symptoms are often very general and difficult to recognize conclusively as mesothelioma. As such, the disease is often diagnosed at a late stage, which can limit patients’ treatment options.

The standard and best-practice has been a multimodal approach of surgery, chemotherapy and radiation. Even with innovations and improvements in care, this standard has not significantly advanced  in comparision to other more common cancers. However, with the increasing access and research regarding immunotherapy and clinical trials some patients are now able to take advantage of these emerging treatments.

Clinical trials often represent final and potentially sole options for care, depending on the severity and stage of their diagnosis. The introduction of immunotherapy, along with promising research being conducted on less-invasive diagnostic tests and studies improving on surgical care, all stand to improve care and outcomes from the standard treatment patients have been presented with previously.

While this standard of care is practiced across all three types of mesothelioma, the nature of how each presents, the tumor makeup and staging can all drastically impact how a patient is able to move forward with their treatment.

Treating mesothelioma

The most common type of mesothelioma presents in the pleura or lining of the lungs due to inhalation of asbestos, known as pleural mesothelioma. Representing about 90% of all mesothelioma diagnoses in the US [2], patients facing pleural mesothelioma have arguably the most available options for treatment, due to the location of the tumors as well as current research being increasingly translational for this area of the body. Depending on location, severity and stage, the standard of treatment is either an extrapleural pneumonectomy or more recently the less invasive lung-sparing pleurectomy/decortication.

Removal of surrounding tissue affected like the diaphragm or lining of the heart, followed by chemotherapy and radiation typically completes the full course of treatment. Some patients who have the appropriate tumor makeup can also participate in ongoing clinical trials, particularly those aimed at the PDL-1 and CTLA4 proteins, which mesothelioma shares with a number of other cancers.

The second most common type, peritoneal mesothelioma, presents in the lining of the abdomen and while surgical options are available, they tend to be less standard due to how this cancer presents across the peritoneal cavity. Often the resection of the tumors and lining of the peritoneum is standard, along with hyperthermic intraperitoneal chemotherapy wash during surgery to increase the odds of shrinking tumors and to reach cancer cells in the affected area. Rounds of chemotherapy and radiation are also part of the standard of care and clinical trials may be an option for select patients [3].

The third type, pericardial mesothelioma, is extremely rare and only accounts for about 1–2% of all diagnoses. Pericardial mesothelioma develops around the lining of the heart and patients are also met with the option of surgery to resect and remove the lining of the heart. However, with such low rates of incidence, the standard of treatment unfortunately often does not offer patients with unique or advanced treatment as the two more common forms can provide [4].

Community & education

Cancer awareness and research can often go hand in hand at providing opportunities for early detection and greater access for patients to clinical trials and advanced treatment options. Mesothelioma is an entirely preventable cancer, which makes knowledge regarding the dangers of asbestos key. Information and details surrounding treatment options and clinical trials can mean life or death for some.

Advocacy groups, data sharing and increased research into the foundations of cancer can provide patients and physicians the tools they need to properly diagnose, treat and care for patients with rare cancers like mesothelioma. September 26th marks Mesothelioma Awareness Day and provides a great opportunity to educate and support this community, while learning the ways we can bring research and translational care to those who can benefit the most.