Medical statistics can be valuable snapshots, but they only tell part of the story. The statistics discussed in this article are addressed to pleural mesothelioma and peritoneal mesothelioma, which develop in the outer lung lining and the abdominal cavity respectively. Over ninety percent of all mesothelioma cases are of these varieties. Currently, the most often quoted average survival period for a patient diagnosed with mesothelioma is about one year. That is an average, however, and opinions among mesothelioma researchers varies based on their own observations and compilation of figures. The National Cancer Institute cites a survival rate of sixteen months after diagnosis for patients with pleural mesothelioma who have been treated surgically, and a survival period of five months for those with an advanced stage of the disease that does not allow for surgical intervention.
A prognosis figure is also a statistic that is impacted by three other important factors:
- The latency period for mesothelioma can be anywhere from twenty to fifty years. Most of the individuals diagnosed with mesothelioma are in their fifties or older and have other, mitigating health factors. Many are or have been cigarette smokers; some have heart problems or general health that is somewhat delicate due to age.
- A mesothelioma diagnosis is often not made until the disease has been present for some time and has developed into a mature, invasive form of cancer. One of the reasons for this fact is that mesothelioma symptoms often don't manifest while the cancer is in its developmental stage.
- The last is that mesothelioma symptoms – shortness of breath, chest pain, pleural effusion, a persistent cough – are also symptoms associated with much more common health problems, particularly for smokers and people over fifty. Those can include heart disease, COPD symptoms, pneumonia, even influenza. Mesothelioma is a relatively rare disease and thus is often not considered in the initial diagnostic considerations.
Mesothelioma Prognosis Factors
One of the critical issues with a mesothelioma diagnosis is the question of whether or not the disease has been caught early enough that surgery is an option. Most mesothelioma diagnoses don't meet this standard but for those that do there is the possibility of slowing the disease substantially. The determination of staging during the diagnostic procedure will dictate the nature of the treatment, which in turn will impact the prognosis for each patient. At this point pleural mesothelioma is the only form of the disease for which a formal staging protocol has been developed, but as oncologists and surgeons have developed experience with the disease they have gotten more aggressive about abdominal surgery for peritoneal mesothelioma.
Treatment for Early Stage Mesothelioma
Usually when physicians opt for surgery with this it means that the cancer is still localized and has not metastasized into the lymph system or into other areas of the body. This is a stage I or stage II presentation for the disease. In the case of pleural mesothelioma, surgery usually includes removal of one or more of the lung lobes on the side of the body where the disease has developed. Pleural mesothelioma always develops on one side of the body.
Other mesothelioma treatment options include chemotherapy and radiotherapy. At this point, medical science has not developed a set of chemotherapy drugs that are effective beyond extending survival time a few months, as stand-alone treatment. The use of chemotherapy and radiotherapy in conjunction with surgery can extend the survival period well beyond the twelve month average. The fact is that all mesothelioma patients who are receiving chemotherapy and radiation treatment are receiving palliative therapy, designed to extend the life for a short period and to ease some of the symptoms.
Impact of Mesothelioma Cell Type on Prognosis
Cell type plays a role in a mesothelioma prognosis analysis. The two types of cells that develop into mesothelioma cancers are epithelioid cells and sarcomatoid cells. Some patients have biphasic mesothelioma, wherein both types of cells are present. Epithelioid cells respond to treatment more readily and the chemotherapy drugs currently available are more effective with epithelioid calls than sarcoma cells. In most studies of mortality rates in mesothelioma patients today, the figures for survival are defined for both epithelial cases and sarcomatoid or biphasic cases. In all instances, the survival periods for patients with epithelial mesothelioma are longer than those with the much less common sarcoma cell present.
Mesothelioma Prognosis Statistics
The figure given for average survival beyond diagnosis is just one perspective on the figures that are available. There are not a lot of mesothelioma case studies that have large populations. Looking past the average, accepted norms are that generally ten percent of all mesothelioma patients will be alive three years after diagnosis and five percent will be alive five years after diagnosis.
Mesothelioma Case Studies
There are fewer case studies of patients who were diagnosed early enough for surgical intervention. One that is often cited, however, is an analysis conducted at the Dana Farber Cancer Institute that followed 120 patients diagnosed from 1980 to 1995, all pleural mesothelioma patients who were initially treated with surgery. Of those 45% were alive two years later and 22% were alive five years later.
In the Dana Farber study, patients with epithelioid mesothelioma fared much better than those with biphasic or sarcomatoid cases. 74% of epithelioid cases were alive after two years and 39% were alive after five years. Of those patients with sarcomatoid or biphasic mesothelioma 20% were alive two years after diagnosis and at the five year mark all had died. Nevertheless, the median survival time for all diagnosed cases was about twelve months.
An Australian study that surveyed 954 cases during the 1980s showed a mean survival time of 11.4 months. A report published by physicians at the Hiroshima University Department of Oncological Surgery surveyed 87 consecutive patients with pleural mesothelioma which produced a median survival period of 13 months for patients who underwent surgery, with 33% still alive at the two year mark.
There are other studies from other countries that show improved results with certain types of treatment, with various combinations of disease stages and malignant cell types but the median survival rate of one year, plus or minus perhaps two months, seems to be a standard range.
Prognosis: The Limits to Statistical Value
Every patient who contracts mesothelioma is still a name rather than a number. The factors that enter into survival rates are myriad and complex: age, relative health, stage of the disease at diagnosis; there is evidence now developing that genetics has something to do with both risk of developing the disease and the likelihood of positive response to treatment.
There is no question that mesothelioma is a lethal and aggressive form of cancer, but even for a disease once considered a death sentence there is no one set of statistics that tell the entire story. Despite its rarity there is significant research being done on diagnostic techniques and non-surgical treatment options: at the moment progress for survival rates is being measured in months. However for each patient, the ultimate result will be dictated by a mixture of factors known and unknown.
- Malignant Mesothelioma Treatment PDQ National Cancer Institute, http://www.cancer.gov/cancertopics/pdq/treatment/malignantmesothelioma/HealthProfessional/page2
- Extrapleural Pneumonectomy in the Multimodality Therapy of Malignant Pleural Mesothelioma-120 Consecutive Patients, Sugarbaker, et al, Annals of Surgery, Sept. 1996
- Lung Asbestos Fiber Content and Mesothelioma Cell Type, Site, and Survival, Leigh, et al, Cancer, June 2006
- Radical Surgery for Malignant Pleural Mesothelioma, Okada et al, Interactive CardioVascular and Thoracic Surgery, 2008
- Gene Therapy for Mesothelioma and Lung Cancer, Steven M Albelda MD, Chest, 1997