All cancers are described as having ‘stages’, which essentially tell a physician how far the cancer has spread. Those who are diagnosed with cancer undergo a series of scans and tests, and these help to determine the stage. When the stage is known, an oncologist is also better able to determine what type of treatment can be used. It should be noted that with a cancer like mesothelioma, symptoms usually don’t appear until the cancer is already in a very advanced stage.

The IMIG System

The International Mesothelioma Interest Group, or IMIG, has developed a system that is most commonly used all over the world to determine the stage of mesothelioma. Some oncologists will use other systems, but this is the most recognized, as it is also based on the TNM staging system, which describes:

  • T – for the position and size of the primary mesothelioma tumor
  • N – for whether or not the cancer has spread to the lymph nodes nearby
  • M – for whether metastases has occurred, which means the cancerous cells have also spread to other parts of the body

By collecting the TNM information, it is possible to determine the stage of the cancer, with 1 being the earliest and 4 being the most advanced. This means that:

  • Stage 1 happens when cells are found in the pleura cells around the lung on just one side of the chest. Within this stage, two categories exist:
    • Stage 1a happens when parietal pleura is present, which means the cancerous cells are also found on the pleura’s outer layer, but only on one side.
    • Stage 1b happens when visceral pleura is present, which means the cancerous cells are inside the pleura’s inner layer, but they have not spread to the diaphragm or lung tissue, and are only found on side of the chest.
  • Stage 2 happens when both the pleura layers have been affected, but still only on side of the chest. Additionally, a tumor mass in the lung’s pleural tissue is present. Sometimes, the cancer has started to spread to the lung tissue or the diaphragm muscle.
  • Stage 3 happens when the covering of the heart (pericardium) or the chest wall have been affected by the cancer, but they could still be removed through surgical methods. Stage 3 can also describe the situation in which the lymph nodes on the side of the chest where the tumor can be found have been affected.
  • Stage 4 describes the situation in which surgery is no longer effective. This could be because the cancer has grown into the peritoneum through the diaphragm, because it has affected multiple parts of the chest wall, it has affected the organs in the chest, it has broken into the pericardium’s inner layer, it has spread to the lymph nodes found on the other side of the chest, or it is found in any other part of the body.

The above information, however, is a guideline only. This is also due to the fact that there are multiple types of mesothelioma, and their stages present in different ways.

Peritoneal Mesothelioma Stages

No official staging system exists for peritoneal mesothelioma. While many physicians will use the TNM system, this is not actually accurate in this case. Peritoneal mesothelioma is usually in metastasis, which means it has spread, and the stage is usually descriptive of the extent of the metastasis. As such:

  • Stage 1 – The cancer hasn’t spread to the lymph nodes and is only present on one side.
  • Stage 2 – The cancer remains on one side, but some metastasis is starting to appear.
  • Stage 3 – Metastasis is now obvious. Fewer treatment options exist, and surgery is usually no longer an option.
  • Stage 4 – The cancer is now present on both sides of the body. Treatment is designed solely to provide relief from the symptoms, not to cure.

Pleural Mesothelioma Stage

With pleural mesothelioma, four stages according to the TNM system are used, and this is an accurate description of the stages of the disease. This is because pleural mesothelioma is much clearer in its presentation. As such:

  • Stage 1 – The cancer is on the lining of one lung, either the inner or outer lining. Prognosis is more favorable in stage 1 than in any other stage, and all treatment options (surgery, radiotherapy, and chemotherapy) are available.
  • Stage 2 – The cancer continues to be present in only one lung. However, there is some metastasis to the diaphragm, chest walls, the lungs, or the lymph node. The prognosis at stage 2 is quite similar to stage 1, and it is possible to receive curative treatment.
  • Stage 3 – In this case, the cancer has invaded the protective lining of the heart, the nearby lymph nodes, the diaphragm, and/or one long. The prognosis depends mainly on the patient’s overall health and age.
  • Stage 4 – This happens when the tumor takes over most of the chest, on both sides. Life expectancy is usually no more than one year. Curative treatment is generally not an option, and only palliative care can be offered.

Pericardial Mesothelioma Staging

Pericardial mesothelioma is incredibly rare. As such, no staging system exists. Furthermore, most patients that do present with this disease are in advanced stages, when no treatment is available anymore. In most cases, people don’t know they have pericardial mesothelioma until they have significant metastasis, at which point it is generally too late.

Stages and Symptoms

Unfortunately, mesothelioma is usually not uncovered until it is in a quite advanced stage. However, some of the symptoms they may experience during stages 1 and 2 include:

  • Persistent coughs
  • Difficulty breathing
  • Chest pain
  • Fatigue
  • Weight loss
  • Fever

These symptoms will become more pronounced during stages 3 and 4. Additionally, those in stage 3 or 4 mesothelioma will usually also experience:

  • Dysphagia, which is difficulty in swallowing
  • Hemoptysis, which is when you cough up blood
  • Pleural effusions
  • Night sweats

How Is Mesothelioma Staged?

In order to stage mesothelioma, physicians and oncologists can use a number of different diagnostic tools. These are all designed to give them a degree of visual information not just of the size of the tumor, but also about how much it has spread. The tools available to them include:

  • The CT scan, which takes several images to create a single 3D image. This is used to determine whether the tumor has spread to the diaphragm or the chest wall.
  • The MRI scan, which demonstrates whether the mesothelioma has spread to nearby organs, the lining of the heart, the chest wall, the pleura, or the lining of the lungs.
  • The PET scan, which determines whether the mesothelioma has spread to lymph nodes, and particularly those some distance away from the original mesothelioma.

Why Does Staging Matter?

Oncologists and other specialists use the stage of the mesothelioma in their patients in order to determine the best type of treatment that can be used, and how likely it is for that treatment to be effective. People who have received an early stage mesothelioma diagnosis are more likely to be offered traditional types of treatment, including radiotherapy, chemotherapy, and surgery. These are designed to cure the disease and extend a patient’s life. If, however, they receive an advanced stage diagnosis, treatment will usually be palliative in nature. Nevertheless, it is possible for these patients to take part in clinical trials, which may help to cure their illness or, at the very least, provide a cure for future sufferers. Unfortunately, once advanced stages of mesothelioma are reached, there is very little that can be done in terms of curing the illness.