What Is the Mesothelioma Staging Process?

Typically, the staging process is used by oncologists to determine the extent of cancer’s spread throughout the body. Like other cancers, the stages of mesothelioma (a type of cancer caused by asbestos exposure) are numbered 1 to 4. For malignant mesothelioma patients, stage impacts prognosis and life expectancy, as well as determines which treatment options are available. In general, the earlier the stage, the better the prognosis. However, life expectancy also depends on factors such as the type of mesothelioma, the tumors’ cell type, and the patient’s overall health.

In addition to reviewing the individual history of asbestos exposure, doctors use a number of screening methods to diagnose a patient’s mesothelioma stage. Commonly, these include imaging tests, blood tests, biopsies, and surgery. Although pleural mesothelioma is the only type with a formal staging system, doctors are able to estimate the stage of cancer development for peritoneal and — to a lesser extent — pericardial mesothelioma.

Too, staging affects the recommended course of treatment. Early-stage patients (usually stages 1 and 2) are often candidates for potentially curative treatment, such as a multimodal plan involving surgery, chemotherapy, radiation, and other emerging treatments or clinical trials. Usually, doctors focus on palliative care for later-stage patients (stages 3 and 4). Palliative care may include chemotherapy or radiation to slow the spread of cancer, as well as procedures like pleurodesis, paracentesis, and thoracentesis to reduce fluid buildup around the affected organs. Removing fluid tends to alleviate pain or discomfort and ease breathing difficulties.

Due to mesothelioma’s long latency period (the time between when the patient was exposed to asbestos and when tumors appear) and the slow onset of symptoms, most patients are diagnosed at stage 3 or 4. By this time, the cancer has already started to metastasize, spreading to different parts of the body from where it started.

Four Stages of Mesothelioma

This is an image of a lung with stage 1 cancer.

Stage 1

    • Characteristics

    • Localized to one side of the body
    • No spread to lymph nodes or other organs
    • No or few symptoms
    • Potentially curative treatment options
    • Best prognosis

This is an image of a lung with stage 2 cancer.

Stage 2 Characteristics

      • Localized to one side of the body
      • Some metastasis to lymph nodes or nearby organs
      • Mild symptoms are easily mistaken for other illnesses
      • Potentially curative treatment options
      • Fair prognosis

This is an image of a lung with stage 3 cancer.

Stage 3 Characteristics

      • Localized to one side of the body
      • Metastasis to lymph nodes or nearby organs
      • Worsening symptoms
      • Palliative treatment options
      • Poor prognosis

This is an image of a lung with stage 4 cancer.

Stage 4 Characteristics

    • Spread to both sides of the body
    • Metastasis to lymph nodes and organs in other areas
    • Worst symptoms
    • Palliative treatment options
    • Worst prognosis

Pleural Mesothelioma Stages

Pleural mesothelioma (i.e., cancer of the chest cavity lining due to inhalation of asbestos) is the most common type of mesothelioma (70 to 90 percent of cases) and the only type with a formal staging system. In total, there are three staging systems for pleural mesothelioma: the TNM staging system, the Brigham staging system, and the Butchart staging system.

Most doctors today use the TNM system, which stands for Tumor, Node, and Metastasis. Developed by the American Joint Committee on Cancer, the TNM system was designed as a tool for doctors to stage different types of cancer (not only pleural mesothelioma) based on the size of the tumor (T), whether the cancer has reached the lymph nodes (N), and the presence and extent of metastasis to other parts of the body (M).

Asbestos causes latent mesothelioma. Think you were exposed? Request a case evaluation to pinpoint the cause and who’s responsible.
Evaluate My Case

TNM staging for pleural mesothelioma

Stage 1
The tumor is localized to the site of origin. The lymph nodes are unaffected and there is no metastasis to other parts of the body.
Stage 2
The tumor is localized to one side of the body but extends deeper into the pleura as well as the diaphragm and/or lung. Nearby lymph nodes may be affected but there is no metastases to other parts of the body.
Stage 3
The tumor is still localized to one side of the body but extends even deeper into the pleura as well as the diaphragm, lung, chest wall, thoracic fascia, heart sac, and/or mediastinal fat. Cancer has spread to lymph nodes on the same side of the body and there is potential metastasis to nearby organs.
Stage 4
The tumor is no longer localized and is not resectable by surgery. Cancer may have spread to distant lymph nodes on the other side of the body and there may be distant metastasis to other organs.

The Brigham and the Butchart staging systems are older than the TNM system but are still used for staging pleural mesothelioma in some cases. The Brigham system stages cancer-based on whether it has spread to the lymph nodes and whether the tumor can be surgically removed. The Butchart system is based chiefly on the location of the primary tumor.

Peritoneal Mesothelioma Stages

Peritoneal mesothelioma (i.e., cancer of the abdominal lining caused by the ingestion of asbestos) accounts for 10 to 30 percent of all mesothelioma cases. Because it is relatively rare compared to pleural mesothelioma, there is currently no formal staging system specifically for peritoneal mesothelioma. However, doctors may use generic cancer-staging guidelines, such as those published by the American Joint Committee on Cancer (AJCC) in its “AJCC Cancer Staging Manual,” in order to approximate a 1 to 4 stage.

Surgical oncologists may also use the Peritoneal Cancer Index (PCI) to assess the extent of peritoneal mesothelioma tumors in the abdominal cavity and whether the cancer has spread to the lymph nodes or other organs. Your PCI score (which can range from 0 to 39) will help determine whether you are eligible for certain treatments, such as surgery to resect the visible tumors (cytoreductive surgery) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) to eradicate any remaining cancer cells. Generally, a lower PCI score indicates fewer, smaller tumors throughout the abdominal cavity, resulting in a better prognosis.

Pericardial Mesothelioma Stages

Due to its rarity (less than 5 percent of all mesothelioma cases) and the fact that it is usually diagnosed posthumously, there is no formal staging system for pericardial mesothelioma (i.e., cancer of the heart lining caused by asbestos exposure). Instead, the severity is primarily gauged by the size of the tumor on the pericardium and whether it can be removed with surgery. As with peritoneal mesothelioma, your oncologist may also use general cancer-staging guidelines to estimate a stage.

Mesothelioma Support Team

Mesothelioma Hub is dedicated to helping you find information, support, and advice. Reach out any time!