Malignant mesothelioma is a rare, asbestos-related cancer that forms on the thin protective tissues that cover the lungs and abdomen.
Mesothelioma is an aggressive cancer that affects the lining of the lungs, heart, or abdomen. Caused primarily by the inhalation of asbestos fibers, mesothelioma is most commonly diagnosed in older individuals who worked with asbestos in an industrial setting. Prognosis for mesothelioma is poor, but early detection and newer treatment methods have given many patients hope for survival.
While the term “asbestos cancer” most often refers to mesothelioma, a number of other cancers are associated with asbestos exposure. Lung cancer can be directly caused by asbestos exposure, and some studies have suggested a link between exposure and other types of cancer.
A layer of specialized cells called mesothelial cells lines the inside of the chest, the abdomen, and the space around your heart. These cells also cover the outer surface of most of your internal organs. The lining formed by these cells is called the mesothelium.
The mesothelium helps protect your organs by making a special lubricating fluid that allows organs to move against each other. For example, this fluid makes it easier for your lungs to move (expand and contract) inside the chest when you breathe. The mesothelium has different names in different parts of the body:
- The pleura coats the lungs and the space in the chest containing the lungs.
- The peritoneum lines the inside of the abdomen and many of the organs in the abdomen.
- The pericardium covers the heart and creates the space that holds the heart in the chest.
- The tunica vaginalis lines the testicles.
Mesothelial tumors can start in any of these linings. These tumors can be non-cancerous (benign) or cancerous (malignant).
Mesothelioma is a rare cancer. It occurs in less than 1% of all cancers in the United States, based on the latest data from the SEER registry. The total incidence in the year 2012, the last year that statistics have been released, states a total of 3,247 patients diagnosed with mesothelioma. Males account for 2,341 of that number and females 906 of the total. The overwhelming majority being male age 60 to 80 plus. Race also is a factor with African-American and Asian mesothelioma victims accounting for 109 and 56 patients, respectfully of the total. The one year survival rate of patients diagnosed with mesothelioma in 2011, and surviving until 2012 is 52.3%.
Malignant mesothelioma (me-zoe-thee-lee-O-muh) is a type of cancer that occurs in the thin layer of tissue that covers the majority of your internal organs (mesothelium).
Mesothelioma is an aggressive and deadly form of cancer. Mesothelioma treatments are available, but for many people with mesothelioma, a cure is not possible.
Doctors divide mesothelioma into different types based on what part of the mesothelium is affected. Mesothelioma most often affects the tissue that surrounds the lungs (pleura). This type is called pleural mesothelioma. Other, rarer types of mesothelioma affect tissue in the abdomen (peritoneal mesothelioma), around the heart and around the testicles.
Mesothelioma doesn’t include a form of noncancerous (benign) tumor that occurs in the chest and is sometimes called benign mesothelioma or solitary fibrous tumor.
he tissue that lines your lungs, stomach, heart, and other organs is called mesothelium. Mesothelioma is a tumor of that tissue. It usually starts in the lungs, but can also start in the abdomen or other organs. It can be benign (not cancer) or malignant (cancer.)
Malignant mesothelioma is a rare but serious type of cancer. Most people who get it have worked on jobs where they inhaled asbestos particles. After being exposed to asbestos, it usually takes a long time for the disease to form.
- Trouble breathing
- Pain under the rib cage
- Pain, swelling, or lumps in the abdomen
- Weight loss for no known reason
Sometimes it is hard to tell the difference between malignant mesothelioma and lung cancer. Your doctor uses imaging tests and a biopsy to make the diagnosis. Malignant mesothelioma is often found when it is advanced. This makes it harder to treat. Treatment may include surgery, radiation, and/or chemotherapy.
NIH: National Cancer Institute
Surgery that preserves the lung, when combined with other therapies, appears to extend the lives of people with a subtype of the rare and deadly cancer mesothelioma, a new study suggests.
Tracking 73 patients with advanced malignant pleural mesothelioma — which affects the lungs’ protective lining in the chest cavity — researchers found that those treated with lung-sparing surgery had an average survival of nearly three years. A subset of those patients survived longer than seven years.
Mesothelioma patients treated with chemotherapy alone, which is standard care, live an average of 12 to 18 months, the researchers said.
Study participants received lung-sparing surgeries and another treatment called photodynamic therapy that uses light to kill cancer cells. Ninety-two percent of the group also received chemotherapy.
The study volunteers achieved far longer survival times, said study author Dr. Joseph Friedberg.
“When you take the [entire] lung out, it’s a significant compromise in quality of life,” said Friedberg. He’s director of the University of Maryland Medical Center’s Mesothelioma and Thoracic Oncology Treatment and Research Center in Baltimore.
“For all intents and purposes, this [lung-sparing surgical approach] is the largest palliative operation known to man, since chances of curing mesothelioma are vanishingly small,” said Friedberg. He completed the research while at his previous post at the University of Pennsylvania.
“Plus, most of these patients are elderly, so preserving quality of life was really the goal,” he added.
About 3,000 Americans are diagnosed with mesothelioma each year, the American Cancer Society says. Many of these people were exposed to the mineral asbestos in industrial occupations, according to the U.S. National Cancer Institute (NCI).
Used in products such as insulation, building shingles and flooring, asbestos dust fibers can be inhaled or swallowed, settling in the lungs, stomach or other body areas. Often, it takes decades after exposure for mesothelioma to develop, the NCI says.
Friedberg and his team performed the lung-sparing surgeries on study participants between 2005 and 2013. Overall average survival was 35 months, the study showed. But survival time more than doubled to 7.3 years for 19 patients whose cancer had not spread to their lymph nodes.
Most of the patients in the study had stage 3 or stage 4 cancer. Typically, Friedberg said, only about 15 to 20 percent of mesothelioma patients are treated with surgery, which often removes an entire lung as well as the diaphragm and the sac surrounding the heart.
Friedberg said that between 20 and 40 percent of pleural mesothelioma patients with the epithelial subtype might be eligible for lung-sparing surgery. He explained that this surgery removes all visible traces of cancer. It typically has fewer complications and a lower risk of dying in the 90 days following the 10- to 14-hour procedure.
“It’s still relatively new that people do lung-sparing surgery for this disease, and it’s not established that this is what we need to do,” said Friedberg.
“I would say this is one of the most lethal cancers known to man. There’s a pressing need for new and innovative treatments,” he noted.
Another mesothelioma expert said he was cautiously optimistic about the new study’s results.
“It’s not a randomized trial and I think they selected out … only those patients who were well enough to get to surgery and those with the epithelial subtype who are the patients who tend to do the best,” said Dr. Gregory Masters.
He is principal investigator with the U.S. National Cancer Institute Community Oncology Research Program at the Helen F. Graham Cancer Center and Research Institute in Newark, Del.
“Taking the best patients is going to skew the study and make the outcome look very good,” added Masters. “But I am encouraged they can take a large group of patients and show such a good outcome at three years.”
Dr. Daniel Petro, a medical oncologist/hematologist at the University of Pittsburgh Medical Center, said lung-sparing surgery for mesothelioma is also done at academic centers such as his, and he was not surprised by the study’s results.
“This [surgical approach] is a step forward with this particular terrible cancer,” Petro said, “and we’ve got to keep coming up with better options to eradicate it.”
The study was published in the December issue of Annals of Thoracic Surgery.
SOURCES: Joseph S. Friedberg, M.D., director, Mesothelioma and Thoracic Oncology Treatment and Research Center, University of Maryland Medical Center, and professor, surgery, and head, Division of Thoracic Surgery, University of Maryland School of Medicine, Baltimore; Gregory A. Masters, M.D., principal investigator, U.S. National Cancer Institute Community Oncology Research Program (NCORP), Helen F. Graham Cancer Center and Research Institute, Christiana Care Health System, Newark, Del.; Daniel Petro, M.D., medical oncologist/hematologist, Hillman Cancer Center, University of Pittsburgh Medical Center; December 2016, Annals of Thoracic Surgery
Malignant mesothelioma is a disease in which malignant (cancer) cells form in the thin layer of tissue that covers the lung, chest wall, or abdomen. It may also form in the heart or testicles, but this is rare.
The type of malignant mesothelioma depends on the cell in which it began. The most common type of malignant mesothelioma is epithelial mesothelioma, which forms in the cells that line organs. The other types begin in spindle-shaped cells called sarcomatoid cells or are a mixture of both cell types. Epithelial mesothelioma may grow more slowly and have a better prognosis than other types.
The major cause of malignant mesothelioma is being exposed to asbestos over a period of time. This includes people who were exposed to asbestos in the workplace and their family members.
After a person is exposed to asbestos, it usually takes at least 20 years for malignant mesothelioma to form.