The TNM Staging System

The TNM staging system is a process through which doctors determine the progression of a patient’s mesothelioma. It is an essential part of the mesothelioma diagnosis and treatment process. Without a staging system, is it impossible to determine how to proceed with mesothelioma treatment.

The T in TNM stands for tumor, and how large and near to organs a tumor is. N stands for lymph nodes, and whether the malignancy has spread to them. The M stands for metastasis, or whether cancer has spread to organs other than the mesothelium. The TNM system was developed by the American Joint Committee on Cancer. It is considered the major mesothelioma staging system.

TNM Stage I

Stage I, or localized mesothelioma, is diagnosed when the malignancy has not spread beyond the membrane that covers the chest wall, called a mesothelium. It may also appear on the lung in the commonly diagnosed pleural form of the disease. Sometimes malignancy may also be localized on the diaphragm or the sac surrounding the heart.

At this stage, mesothelioma may be successfully addressed by surgically removing the diseased cells as well as some surrounding tissue. If the malignancy is localized but in more than one location, a pleurectomy may be performed, in which the membrane surrounding the lung is removed. Chemotherapy may be used in conjuncture with surgery to fight stage I mesothelioma.

TNM Stage II

Stage II mesothelioma means that the malignancy has moved into the lungs and/or diaphragm, though it has not spread to the lymph nodes or distant locations.


When the disease spreads to the lymph nodes, or it invades the mediastinum or the lining of the abdomen, stage III is diagnosed.

TNM Stage IV

Finally, a stage IV diagnosis indicates that malignancy has spread to organs far from the respiratory system. It may affect critical structures such as the esophagus, heart, or spine.

Testing For Mesothelioma

Staging is accomplished through a variety of tests and procedures. They may include a chest X-ray, CAT scan, MRI, and endoscopic ultrasound. Endoscopic ultrasound is also sometimes employed in the biopsy of potentially effected organs.

Treatment Options

Once staging is complete, the diagnosis is taken into consideration along with the age and overall health of the patient in order to determine a course of treatment. Treatment may include traditional medical procedures and/or new mesothelioma treatments.

Traditional treatment refers to surgery, chemotherapy, and radiation therapy. These procedures are typically used cooperatively in order to remove malignancy and then fight its return or spread. This is a typical course of action taken to treat the majority of cancer patients.

Recent Treatment Developments

New mesothelioma treatments include an array of procedures, such as gene therapyphotodynamic therapy, immunotherapy, and intensity modulated radiation therapy. The development of new chemotherapy agents is also being explored. Other radical treatments are sometimes used in conjunction with or independent of traditional medial therapy to treat advanced stages of mesothelioma.

The TNM staging system is an integral part of determining the best course of treatment for a mesothelioma patient. This system allows doctors to evaluate the severity and spread of the disease before recommending treatment and providing a prognosis.