ted, but limiting healthy cell damage remains an issue for both chemotherapy treatment and radiation. Sometimes radiotherapy is used during the course of surgery so that physicians can target precisely the diseased tissue remaining in the body while it is still exposed on the operating table.
Photodynamic therapy has been developed to allow for the targeting of radiological cancer treatment as well. Still in experimental stages, photodynamic therapy essentially uses photosensitive medications that are injected into the patient and activated by light when they reach the appropriate area to be treated. This promising technique is under study in several clinical trials, as is immunotherapy – another method of attacking cancer cells with specific molecules.
There are three or more sets of guidelines for the staging of malignant mesothelioma cases. The most common is the TNM system, an acronym that references tumors, nodes and metastases. TNM is used to stage lung cancer, ovarian cancer and other types of the disease, and has been approved as a standard by the American Joint Committee on Cancer, an organization that counts the National Cancer Institute among its founding members.
Currently pleural mesothelioma is the only form of the disease that has a formal staging structure. It is the most common form of a relatively rare disease; accordingly physicians assess the spread of cancer in peritoneal mesothelioma or pericardial mesothelioma based on less form analyses of the presence of malignancy.
Briefly, the four TNM stages are as follows:
Stage I: Mesothelioma is present in the pleura covering either the right or left lung. It may have spread to the pericardium or the diaphragm or lung on the same side of the body. There is no evidence of cancer in the lymph nodes.
Stage II: Mesothelioma meets all of the conditions of stage I with the additional spread to lymph nodes near the malignant tissue in the pleura and on the same side of the body.
Stage III: Mesothelioma has advanced into the chest wall, the heart, the esophagus or possibly the ribs on the same side of the body as the original pleural malignancy. There may or may not be lymph node involvement.
Stage IV: Mesothelioma has moved to the opposite side of the body, impacting the pleura on the other lung as well as the opposite lung itself, and possibly extending to organs in the abdominal cavity. Metastases have occurred in several areas.
Malignant Mesothelioma Prognosis
Surgery to resect malignant tissue is generally a viable choice with stages one and two, and often with stage three. In the latter case, it depends on the location of the extended malignancy. In stage two and stage three cases, the surgery may involve only a partial removal of malignant tissue, a process referred to as "debulking." In all cases, a regimen of chemotherapy and usually radiotherapy follows the surgical procedure.
In cases where surgery has been performed and an aggressive chemotherapy program undertaken, the prognosis for mesothelioma patients who are otherwise healthy patients may extend to eighteen months or beyond. If the cancer was at stage one or stage two, the outlook for a reasonable survival period can be encouraging. Unfortunately, the median survival period for mesothelioma patients in general hovers at around one year. Some studies have shown the figure to be thirteen months; others closer to eleven months or less. But the value of a surgical intervention followed by chemotherapy seems to be well established; while most gains are in months some are in years.
Mesothelioma Clinical Trials
There is an excellent database of current clinical trials underway for mesothelioma treatment at the National Institutes of Health (NIH) website ClinicalTrials.gov. Most of them evolve around the use of various chemotherapy drugs in combination with one another. The two drugs that have proven to impact mesothelioma tumors with some success are pemetrexed and cisplatin; these are the only two approved by the FDA for mesothelioma treatment.
The drugs are effective against some forms of mesothelioma m