Clapper, Patti, Schweizer and Mason

Mesothelioma is a rare, aggressive type of cancer caused by exposure to asbestos. When asbestos fibers are inhaled or ingested, they can embed into the lining of the mesothelium, or protective sac lining surrounding the lungs, abdomen or heart. The three main types of mesothelioma are pleural (lungs), peritoneal (abdomen), and pericardial (heart). Malignant pleural mesothelioma is the most common, whereas peritoneal accounts for 20-30% of all mesotheliomas. 

Peritoneal mesothelioma is more common in males and most patients are between 65 and70 years old, although there is a case of one patient being just 22 years old. The diagnosis of peritoneal mesothelioma often presents late due to the vague symptomology of the cancer. 

Most common presenting symptoms are non-specific, such as weight loss, abdominal pain, bloating, and malaise. Because of a long latency period between time of exposure and development of symptoms, along with it being hard to connect the symptoms with an accurate identification of mesothelioma, treatment mostly focuses on pain relief and palliative care. 

There are limited options for treating peritoneal mesothelioma. Palliative treatments are intended to slow cancer progression and to provide symptomatic relief. Mulitmodality treatment is the standard therapeutic option as surgery and intraperitoneal chemotherapy alone have been proven to be ineffective. Cytoreductive surgery that results in debulking or removing all or most of the tumor, combined with chemotherapy and radiotherapy have been most effective.

Overall survival rates for all types of mesothelioma remain poor, with a median survival rate being around 10 months. Female patients often fare better than male patients. Prognosis is also associated with age, tumor size, tumor growth, and ability to remove surgically.

Pemetrexed (also known as Altima) is a front line chemotherapy drug specifically approved to treat mesothelioma. Often pemetrexed is combined with cisplatin, and clinical trials have shown that this leads to longer survival times. Despite research, peritoneal mesothelioma has many diagnostic and treatment challenges. Recent studies are investigating identifying biological and tumor markers that could help with earlier diagnosis, which would increase treatment options and improve prognosis. 

If a patient presents with abdominal pain and an unusual mass in the peritoneum, physicians are encouraged to ask about any prior asbestos exposure and to check for mesothelioma. Linking occupational exposure can help make an accurate, early diagnosis, which is key to longer survival.