The European Society for Medical Oncology (ESMO) is not optimistic about immunotherapy to treat patients who have received a mesothelioma diagnosis.

Mesothelioma is a rare cancer, almost exclusively linked to asbestos exposure. Mesothelioma starts in the lining of an organ, most often in the pleura, which is the lining of the lungs. Symptoms often don’t become apparent until 20 to 50 years after asbestos exposure.

The disease is usually fatal within two years of a mesothelioma diagnosis, due to latency of discovery.

ESMO Study

ESMO conducted a study to see if immunotherapy drug pembrolizumab could extend survival of patients with mesothelioma who had already been treated with chemotherapy. Pembrolizumab is the generic form of Keytruda, made by Merck.

Patients diagnosed with malignant pleural mesothelioma in their lungs who had pembrolizumab experienced no survival differences compared with those who received standard chemotherapy.

The next step could be to see if a combination of using pembrolizumab in combination with first-line chemotherapy improves patient longevity.

According to a Medscape.com article, researchers expressed disappointment in the performance of pembrolizumab, but recognized that mesothelioma “is aggressive and difficult to treat.”

Medscape quoted study investigator Sanjay Popat, MD, PhD, a thoracic medical oncologist at the Royal Marsden Hospital NHS Foundation Trust in London, England, as saying even though “nearly four times more patients” responded to the immunotherapy drug compared with regular chemo, “unfortunately these responses did not delay progression or improve survival.”

Other U.S. companies are also looking into treatment for pleural mesothelioma.

Why a Mesothelioma Diagnosis is Dire

According to the World Health Organization, more than 125 million people around the world are exposed to asbestos at the workplace because the material is used for insulation, roofing, water supply lines, gaskets, brakes and more.

People who develop mesothelioma often don’t realize they have it until the disease has progressed to the point that breathing is inhibited or a persistent cough is bothersome. To diagnose mesothelioma, patients often will receive an x-ray, pulmonary function test, CT scan, or biopsy.

In addition to pleural (lungs) mesothelioma, the cancer can strike the lining of the chest cavity near the heart or the lining of the abdomen, causing pain in the stomach or constipation. The lining of the abdomen becomes affected by mesothelioma when the patient has swallowed asbestos fibers. Seventy-five percent of all cases of mesothelioma start in the chest cavity.

According to WebMD.com, respiratory failure or pneumonia is usually what causes the death of a patient with pleural mesothelioma.

Routes of Asbestos Exposure

Certain occupations may lead to more asbestos exposure than others. Among the jobs with a high risk of asbestos exposure are:

• Shipyard worker
• Power plant worker
• Mechanics
• Machinery operators
• Industrial insulators
• Construction workers
• Firefighters
• Steel mill workers
• Boilermakers
• Railroad workers
• Asbestos miners
• Demolition workers

Mesothelioma also is a cancer related to asbestos exposure that occurred when the World Trade Center towers were hit by two planes in the 9/11 terrorist attack. According to news reports, more than 100,000 gallons of asbestos, mercury, fiberglass and benzene was in the toxic dust inhaled by people throughout the city. Because only 18 years have passed since that tragedy, medical experts predict an uptick in mesothelioma among New Yorkers in coming years.