Malignant mesothelioma is a rapidly progressing cancer that is usually not diagnosed until the late stages of cancer. Staging is a system for indicating how far the cancer has spread. Treatment options and prognosis greatly depend on the patient’s stage of mesothelioma.
Currently, pleural mesothelioma is the type most likely to be staged, as it occurs more frequently, and therefore has been studied more extensively. Staging is based on the results of the patient’s diagnostic procedures such as blood tests, biopsies, imagining tests, and physical exams.
The TNM Staging System
Out of the three staging systems in place for cancer the American Joint Committee on Cancer (AJCC) TNM system is the one most likely to be used to describe the growth and metastasis of pleural mesothelioma. By using the TNM system coupled with previous patient’s case progression, doctors and other medical specialists can provide an educated estimate as to how and where pleural mesothelioma is likely to spread.
This staging system is based on three key pieces of information, Tumor, Node, and Metastasis respectively. These three factors indicate the spread of the primary tumor, if part of the lymph node system has been affected, and whether or not the cancer has metastasized (or spread) to other organs outside the point of origin. Mesothelioma is an aggressive cancer that is likely to spread to other vital organs at an accelerated rate. The American Cancer Society notes that the most common sites for metastases are the pleura on the other side of the body, the lungs, and the peritoneum. In the later stages (stage III and stage IV) organs such as the brain and liver can also be affected. The TNM system is further detailed with the addition of numbers following the letters. These numbers advance in numerical order; the higher the number the more advanced the cancer.
Other Areas Mesothelioma Can Spread
Due to the probability that the lymph node system will be affected by mesothelioma, the cancer is able to travel well beyond the point of origin. This means that not only can the main (or original) tumor grow in size, but other tumors in distant locations can form. Beginning in the mesothelium, which is the layer of tissue surrounding the chest and abdomen, mesothelioma can grow deeper, affecting the muscle of the lung or diaphragm itself. Other locations include:
- The spine
- Through the heart lining or onto the heart itself
- Any organ located in the mediastinum, which is the esophagus, trachea, thymus, and blood vessels
- Through the diaphragm and into the peritoneum
- The fatty part of the mediastinium
Based on this detailed information, doctors can then assess whether a patient’s mesothelioma is resectable or unresectable.
Resectable mesothelioma—means the doctor believes the whole of the visible tumor can be removed by surgical means. Generally speaking, most stage I, II, and some stage III mesotheliomas have the potential to be resectable; however, there are exceptions. The subtype of the mesothelioma, as well as the patient’s general health and ability to undergo surgery play an important factor.
Unresectable mesothelioma—this is generally the case of the majority of stage IV mesothelioma. This means that the cancer has grown or metastasized beyond the point of surgical removal. Patients who are deemed to have unresectable mesothelioma are given palliative treatment options, which help to alleviate symptoms, in lieu of curative procedures and treatments.
The earlier mesothelioma is diagnosed, the more treatment options a patient has. Those who suspect they have worked near or handled asbestos, or are currently experiencing early symptoms of the disease, are encouraged to speak with a medical professional regarding their chances of developing the disease.