Malignant peritoneal mesothelioma is a rare cancer that originates in the peritoneum. The peritoneum is a thin membrane that lines the abdominal cavity and covers most abdominal organs, such as the intestines and liver. This membrane has two layers with a small amount of lubricating fluid between them, allowing the organs to move smoothly. In peritoneal mesothelioma, malignant cells develop within this lining, disrupting its normal function.
Causes of Peritoneal Mesothelioma
The most well-established cause of malignant peritoneal mesothelioma is exposure to asbestos. Asbestos is a naturally occurring mineral with microscopic fibers that, when inhaled or ingested, can travel through the body and become lodged in the lining of the abdomen.
Once embedded in the peritoneum, these sharp fibers can cause persistent irritation and chronic inflammation. Over several decades, this ongoing cellular damage can lead to genetic mutations in the mesothelial cells, causing them to grow and divide uncontrollably, forming tumors. While asbestos exposure is the primary risk factor, other less common factors, like exposure to the mineral erionite or genetic predispositions, have also been suggested as potential contributors.
Recognizing the Symptoms
The symptoms of peritoneal mesothelioma are often subtle and non-specific, which can make early recognition challenging. Many initial signs can be mistaken for more common gastrointestinal issues. One of the most prevalent symptoms is abdominal swelling or bloating, caused by the buildup of fluid in the peritoneal cavity, a condition known as ascites.
Abdominal pain is another frequent complaint, often described as a dull, persistent ache that may worsen over time. Patients may also experience unexplained weight loss, a general feeling of fatigue, and a loss of appetite. Changes in bowel habits, such as constipation or diarrhea, can occur if tumors press on the intestines. Because these symptoms overlap with numerous other conditions, diagnosis is often delayed.
The Diagnostic Pathway
The process of diagnosing peritoneal mesothelioma begins with a physical examination and a review of the patient’s medical history, including any known asbestos exposure. The next step usually involves imaging tests. A computed tomography (CT) scan of the abdomen and pelvis is one of the most common tools used to visualize the peritoneum, identify tumors, and detect ascites.
While imaging can reveal abnormalities, it cannot provide a definitive diagnosis. The only way to confirm a diagnosis of malignant peritoneal mesothelioma is through a biopsy. This procedure involves taking a small tissue sample from the peritoneum for examination by a pathologist. Often, the biopsy is performed using laparoscopy, a minimally invasive technique to view the organs and collect tissue samples. The pathologist will then analyze the cells’ characteristics to distinguish mesothelioma from other types of cancer.
Current Treatment Modalities
The standard of care for eligible patients is a two-part procedure. The first component is cytoreductive surgery (CRS), where a surgeon removes all visible tumor nodules from the peritoneal lining and the surfaces of the abdominal organs. The goal of this extensive operation is to leave no visible trace of the cancer behind.
Immediately following CRS, the second part of the treatment is administered. This is known as Hyperthermic Intraperitoneal Chemotherapy (HIPEC). During this procedure, a heated, sterile chemotherapy solution is circulated throughout the abdominal cavity. The heat enhances the effectiveness of the chemotherapy drugs, allowing them to penetrate and destroy any remaining microscopic cancer cells.
For individuals who are not candidates for this intensive surgery, systemic chemotherapy is the primary treatment option. This involves administering anti-cancer drugs intravenously to attack cancer cells throughout the body. Immunotherapy and targeted therapy are also offering additional options for managing the disease.
Understanding the Prognosis
The prognosis for an individual with malignant peritoneal mesothelioma is influenced by a variety of factors. The stage of the cancer at diagnosis is a primary consideration; earlier-stage disease is associated with a more favorable outcome. The patient’s overall health and age also play a part, as they can affect the ability to tolerate aggressive treatments.
Another important element is the histological subtype of the cancer cells. The epithelioid subtype, which is the most common, has a better prognosis than the sarcomatoid or biphasic subtypes. The completeness of the cytoreductive surgery is also a major determinant of survival. Patients who have all visible tumors successfully removed have better long-term results. Survival statistics are averages and cannot predict an individual’s specific outcome.