Mesothelioma Stages

Mesothelioma has four stages, and like most cancers, they are labeled stage 1 through stage 4. A patient's treatment plan and prognosis depend on this staging system, which is based on how far the cancer has spread through the body.

Mesothelioma Vets - Stages

What Are the Stages of Mesothelioma?

Like most types of cancer, mesothelioma has four stages, labeled stage 1 through stage 4. The stage indicates how far the mesothelioma has spread through the body. A mesothelioma patient’s treatment plan and prognosis often depend on the stage at which they are diagnosed.

Pleural mesothelioma, the most common of all three types, is the only diagnosis with a formal staging system, although doctors are still able to estimate stages for peritoneal and pericardial mesothelioma. A combination of imaging scans, blood tests, and biopsies are used as staging tools.

The earlier a patient is diagnosed with mesothelioma, the better their potential outcome. However, prognosis also depends on other factors, such as the type of mesothelioma, the cell structure, and the patient’s general health.

Doctors will recommend a treatment plan based on the stage. Early-stage patients, which includes patients diagnosed at stages 1 and 2, often follow the curative treatment route. This may include surgery, radiation, chemotherapy, immunotherapy, and clinical trials. Those diagnosed with mesothelioma at stages 3 or 4 will likely focus on palliative care options, which include radiation or chemotherapy to slow tumor growth and prevent the cancer from spreading. Pleurodesis, paracentesis, and thoracentesis are standard procedures used to drain excess fluid from the affected organs. These procedures also help relieve pain and ease breathing difficulties.

Because of mesothelioma’s long latency period — the time between when the patient’s asbestos exposure occurs and when tumors appear — and the slow onset of symptoms, most patients are diagnosed with this rare disease at stage 3 or 4. At this point, the cancer has already started to metastasize, spreading to different parts of the body from where it started.

Mesothelioma: The Four Stages

Stage 1 Mesothelioma Characteristics

Tumors are localized to one side of the body
Cancer has not spread to lymph nodes or other organs
Few or no symptoms

Stage 2 Mesothelioma Characteristics

Tumors are localized to one side of the body
Some tumor metastasis to lymph nodes or nearby organs
Mild symptoms can be easily mistaken for other illnesses

Stage 3 Mesothelioma Characteristics

Tumors are localized to one side of the body
Tumor metastasis to lymph nodes or nearby organs
Worsening symptoms

Stage 4 Mesothelioma Characteristics

Tumors have spread to both sides of the body
Tumor metastasis to lymph nodes and organs in other parts of the body
Worst symptoms

Stages: Pleural Mesothelioma

Pleural is the only type of mesothelioma with a formal staging system. There are three different methodologies: the TNM staging system, the Brigham staging system, and the Butchart staging system.

Of these three, the most common is the TNM system, which stands for Tumor, Node, and Metastasis. The American Joint Committee on Cancer (AJCC) designed the TNM system for staging many different types of cancer, including mesothelioma. It’s based on tumor size (T), whether cancer cells have moved into the lymph nodes (N), and the extent of spread, or metastasis to other sections of the body (M).

Pleural Mesothelioma: TNM Staging

The tumor is localized or is only affecting the tissue or organ where it originally formed and has not netastasized to the lymph nodes. There is no metastasis to other areas in the body.
The tumor remains on just one side of the body but has spread to the pleura as well as the diaphragm or lung. Specific lymph nodes may be affected, but the cancer has not spread to any other areas of the body.
The tumor stays localized to one side of the body but now extends into the pleura, diaphragm, chest wall, thoracic fascia, and the heart sac. The lymph nodes on that entire side of the body may be affected, and there is a possibility the cancer has metastasized to nearby organs.
The tumor has spread significantly and cannot be surgically removed. Cancer cells have likely spread to lymph nodes on another part of the body, and there may be distant metastasis to other organs.

The Brigham and Butchart staging systems are older than the TNM system but are still used for staging pleural mesothelioma in specific cases. The Brigham system determines the cancer stage based on whether it has reached the lymph nodes and is resectable (removable via surgery). The Butchart system relies on the location of the primary tumor.

Stages: Peritoneal Mesothelioma

This type of mesothelioma affects the abdominal cavity and only accounts for 10 to 30 percent of all cases. Peritoneal mesothelioma is extremely rare, and there’s no formal staging system in place. Doctors may rely on more generic cancer-staging guidelines, which are found in the AJCC’s “Cancer Staging Manual,” to approximate a stage between 1 and 4.

The Peritoneal Cancer Index (PCI) is used to determine the extent of peritoneal mesothelioma tumors in a patient’s abdominal cavity and whether or not the cancer has spread to nearby organs or lymph nodes. A PCI score ranges from 0 to 39. Lower scores indicate smaller tumors and a better prognosis. A PCI score also helps doctors determine whether surgery is feasible, or whether a procedure like Hyperthermic Intraperitoneal Chemotherapy (HIPEC), which eradicates remaining microscopic cells, will be beneficial for the patient.

Stages: Pericardial Mesothelioma

Fewer than 5 percent of all mesothelioma cases are classified as pericardial, and, unfortunately, many aren’t discovered until after the patient has died. Similar to peritoneal mesothelioma, pericardial mesothelioma doesn’t have a formal staging system, so other general cancer-staging guidelines are often used to approximate a stage. Surgeons will also examine the tumor or tumors on the patient’s pericardium and determine whether they can be surgically removed.