Sadly, it is rare that a favorable mesothelioma prognosis is achieved. This is because malignant mesothelioma remains dormant for 2 to 5 decades after initial exposure to asbestos.
This means the cancer has often advanced to Stage 3 or Stage 4 before a physician makes the correct diagnosis. By this time, the cancer has often spread from its original location to other areas in the body, lowering treatment success rates.
Similar to other forms of cancer, a person’s mesothelioma life expectancy depends on several factors:
- Type of cancer
- Location and size of tumor
- Cell type
- Stage of the cancer at the point of diagnosis
- Ability of the patients to receive and respond to treatment
- Overall health and age of the individual
- Amount to which the cancer has spread or metastasized.
Determining a Mesothelioma Prognosis
There are several factors that contribute to either a favorable or unfavorable mesothelioma prognosis:
The first method by which the cancer is classified is by the type of tissue affected. Epithelial mesothelioma typically results in the most positive prognosis and is also the most common form, comprising 50% of all cases. The second is sarcomatoid mesothelioma, which accounts for 16% of cases, and the third, biphasic, is a combination of the other two forms and accounts for 34%. Other types are extremely rare.
Of the three, the epithelial subtype is the most responsive to treatments, while sarcomatoid, the most aggressive, has been unresponsive to chemotherapy and shows early relapse after surgery. The third subtype, biphasic, varies depending on the percentage of sarcomatoid cells mixed with the epithelial variant.
The most favorable mesothelioma prognosis awaits those under age 50 with the epithelial subtype and no lymph node involvement. According to research, survival numbers for this group are improving, but they vary depending on the patient’s treatment choice.
Location and Size of Tumor
The types of cancer can also be differentiated based on the location on the primary tumor. The first and most common form is pleural mesothelioma, which is located in the lining of the lungs. According to research, in cases of pleural mesothelioma, a tumor tends to be present in only one lung at a time, with a right-to-left preference of 60% to 40%.
Another common type is peritoneal mesothelioma, which is located in the abdominal lining. The same study found that while pleural mesothelioma occurs four times more often in men than women, both sexes seem to be equally represented with peritoneal mesothelioma.
Other mesotheliomas can occur in different locations, including in the pericardial region, or lining of the heart, and (rarely) in testicular tissue. When this cancer has spread to other areas of the body, the prognosis is usually less favorable. Conversely, those with tumors that have not spread and can be surgically removed have a much better mesothelioma prognosis.
Stage of the Disease
Due to its long latency period, mesothelioma is often not diagnosed until its late stages, thus decreasing the likelihood of a positive prognosis.
Stage 1 mesothelioma has yet to spread to other areas beyond the area of tumor origin. Because of this, surgery is a popular treatment option. Stages 2, 3, and 4 are characterized by a metastasis (spread) of the tumor. This makes surgery less effective, if even an option at all. While numbers and statistics provide a general picture, it is important to remember that each person is unique, and statistics cannot predict what will happen in individual cases.
Because of the typically late stage of the cancer at the usual point of diagnosis, it is likely that the cancer has spread. The greater the extent of metastasis, the more likely it is that the mesothelioma prognosis will be unfavorable. Because doctors are aware that this form of cancer has a tendency to metastasize, they can keep an eye on the tumor and other areas of the body that may be susceptible to future involvement.
Because the origin of the cancer is most frequently the lungs, an organ that allows blood and oxygen to flow through it rapidly and frequently, it is relatively easy for the cancerous cells to receive the nourishment they need and spread.
Patients who have better overall health and are younger in age typically have a more favorable prognosis than those who are older or have other health issues. Additionally, nonsmokers or those who quit smoking tend to have a better prognosis than patients who continue to smoke.
Generally those who experience severe symptoms and a lack of relief from palliative treatments have the poorest prognosis. Symptoms such as chest pain and shortness of breath are often signs that the cancer has progressed to a later stage.
Mesothelioma is caused by exposure to asbestos. Because asbestos use was common in male-dominated careers, such as chemical and power plants, more men have been diagnosed with the disease than women. Women, in turn, have been in fewer clinical studies, so the information is not as abundant. However, according to the University of South Wales, women may have a better prognosis due to a larger amount of estrogen, which the university believes may lead to tumor suppression.
While survival rates differ from patient to patient, the American Cancer Society conducted a study of 2,959 mesothelioma patients and found that 37% of those under the age of 45 survived more than 5 years after diagnosis. On the other hand, with patients between the ages of 45 and 54, 20% survived more than 5 years. These statistics are fairly optimistic when compared to other data regarding mesothelioma survival rates. Because the average age for mesothelioma diagnosis is 65, the probability that the cancer is generally more advanced is greater, leaving the 5-year survival rate less favorable.
Currently, only 40% of all patients survive 1 year after diagnosis, and only 10% survive past 5 years. These rates have improved greatly over the past 10 years and will hopefully continue to improve as researchers develop new means of diagnosing the illness as well as treating it.
Improving the Mesothelioma Prognosis
Scientists continue to research advances in diagnostic tests, an example of which is the Mesomark assay for quicker diagnoses, as well as new treatment options, such as immunotherapy.
The Division of Thoracic Surgery and Department of Pathology of Brigham and Women’s Hospital in Massachusetts recently conducted a study of 636 patients diagnosed with pleural mesothelioma. They found that those who had an extrapleural pneumonectomy experienced extended survival compared to patients who underwent other, less aggressive surgeries and treatments.
Although there are risks involved, patients may wish to volunteer to be part of a clinical trial. Clinical trials involve administering to mesothelioma patients new drugs that are currently not approved by the Food and Drug Administration. With these clinical trials, certain risks are involved. However, the benefits of these trials may greatly outweigh the risks.