Prognosis is a term referring to the likely outcome of a particular individual’s illness or disease. A patient’s prognosis is directly related to their life expectancy and survival rates. Mostly, these are statistical projections based on previous cases of mesothelioma in similar patients.
The prognosis for patients with mesothelioma is generally unfavorable. This is due in part to the latency period of this disease, causing it to be diagnosed in the later stages of cancer. Diagnosis in stage III and IV generally means the cancer location and size have spread beyond the point of origin to other organ systems, and possibly the lymph nodes. This greatly hinders surgical procedures as a means of removing the malignancy. Malignant mesothelioma typically lies dormant for anywhere from two to five decades before symptoms begin to present, following asbestos exposure.
Mesothelioma is a deadly form of cancer and is comprised of four subtypes; all currently have no known cure. The four types of mesothelioma combine for an estimated 2,000 to 3,000 new cases diagnosed in the United States each year. The highest percentage of cases diagnosed is pleural mesothelioma, which develops in the lining of the lungs. Peritoneal mesothelioma is a cancer affecting the lining of the abdomen, and pericardial mesothelioma affects the lining of the heart. The rarest form of this disease, testicular mesothelioma, is characterized by tumors found in the tunic vaginalis. Overall symptoms among mesothelioma include:
- Shortness of breath
- Coughing
- Chest pains
- Loss of muscle function
- Fluid buildup in the lungs
- Coughing up blood
- Fatigue
- Weight loss
Exposure to Asbestos
The cause of mesothelioma has been overwhelmingly linked to asbestos exposure. Asbestos is a fibrous naturally-occurring material that forms from the amalgamation of several different minerals. The fibers that comprise asbestos are friable and hard, making them capable of easily breaking apart and becoming airborne. Once inhaled, these tiny fibers imbed themselves within various tissues of the body. Asbestos began as a widely used material that was a cost-effective component of various construction materials, consumer and household products. Asbestos exhibited a strong resistance to heat, electricity and chemicals, resulting in heavy use across several industries.
However, during the 1960s asbestos was discovered to have detrimental effects pertaining to people’s health. Among other diseases and illnesses caused by asbestos exposure, mesothelioma can continue to impact those individuals exposed decades later. Despite legislative regulations on asbestos in 1989, the mineral is still permitted for use in some products. Mesothelioma exhibits extremely long latency periods of anywhere between 20 and 50 years, meaning symptoms of mesothelioma may not begin to present until decades after the exposure has occurred.
Determining Prognosis
There are several factors that will help determine a patient’s prognosis, which usually include:
Type of Tissue Affected
Cancer is first classified in accordance with which type of tissue is affected. In the case of mesothelioma, epithelial mesothelioma is the most common form comprising nearly 50 percent of all cases. This form of mesothelioma is regarded as having the most positive prognosis. Sarcomatoid mesothelioma accounts for 16 percent, while biphasic, a combination of the two forms, accounts for 34 percent. Epithelial mesothelioma has the most promising prognosis because it has been found to respond the best to various treatments.
Conversely, sarcomatoid mesothelioma is an aggressive form of cancer, known to be refractory to chemotherapy and demonstrate early relapse in surgeries. Biphasic’s prognosis is reliant upon the percentage of sarcomatoid cells mixed with the epithelial variant.
The most favorable prognosis is generally assigned to those under the age of 50 with the epithelial subtype, exhibiting no lymph node involvement.
Location and Size
The variation of mesothelioma can also be distinguished based on the location of the primary tumor. The most common form is pleural mesothelioma, which is located in the lining of the lungs. Research indicates that pleural mesothelioma tumors tend to be located in only one lung with a right to left preference of 60 to 40 percent respectively.
Peritoneal mesothelioma is another common type of mesothelioma, which is located in the abdominal lining. This form of mesothelioma is unique in that while other forms tend to present in males, peritoneal seems to be equally represented in both sexes.
Other mesotheliomas occur in locations such as the pericardial lining of the heart, but most rarely in testicular tissue. As the malignancy spreads to other areas of the body, prognosis becomes less favorable.
Staging
Mesothelioma, due to its aforementioned latency periods, is usually not diagnosed until the cancer is in an advanced stage. There are three distinct staging systems that can be utilized to determine the progression of mesothelioma: the Brigham system, the Butchart staging system, and the TNM system. All three of these systems order the stages one through four, increasing in severity. In stage I of mesothelioma the tumor has yet to spread to other areas of the body and surgery remains an option. As the stages progress and metastasis occurs, surgical treatments become less and less likely, affecting prognosis.
Metastasis
Metastasis refers to the spread of the cancer from a point of origin to other systems, tissues, and organs within the body. This spread is more likely in mesothelioma due to its tendency to originate in the lungs where blood and oxygen pass through rapidly and frequently, allowing for the malignant cells to travel throughout the body after entering the bloodstream.
General Patient Health
Those patients who are younger and exhibit overall better health has a more favorable prognosis, as opposed to those who are older or suffer from other health issues. Additionally, non-smokers or those who quit, tend to have a better prognosis than smokers.
Commonly, patients presenting with severe symptoms, or a lack of relief from palliative treatments, may have a weakened prognosis. Symptoms such as chest pain and shortness of breath are often signs that the cancer has progressed to a later stage.
Survival Rates
Survival rates for patients vary on a case-by-case basis, however, studies conducted by the National Cancer Institute involving 2,959 mesothelioma patients, found that 37 percent of those patients under 45 survived more than five years after diagnosis. Patients between the ages of 45 and 54, saw a survival rate of 20 percent over five years. These statistics are fairly high in comparison to other data regarding mesothelioma survival rates. This probably accounts for the fact that the average age for mesothelioma diagnosis is 65, meaning the probability that the cancer is more advanced is greater in that age group, leaving the 5-year survival rate less favorable.
Currently, only 40 percent of all patients survive one year after diagnosis and only 10 percent survive past 5. These rates have improved greatly over the last 10 years and will hopefully continue to advance as researchers develop new means of early diagnosis, as well as improved treatment and therapy options.
Mesothelioma Resources
Receiving a diagnosis of mesothelioma can be an overwhelming time for patients and their loved ones. Patients will likely encounter numerous concerns and questions throughout the diagnostic and prognostic processes. Mesotheliomaprognosis.org is dedicated to providing resources for both patients and their families. Those who have been affected by mesothelioma are urged to receive a mesothelioma information packet, delivered free of charge within 24 hours.
