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Mesothelioma Stages

Doctors stage mesothelioma according to factors that indicate its progression. The mesothelioma stages range from Stage 1 (most treatable) to Stage 4 (fewest curative treatment options). The system for mesothelioma staging is different for each primary type of mesothelioma.

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Written by Jenna Campagna, RN

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How Doctors Determine Mesothelioma Staging

The staging of mesothelioma involves tests to determine what stage, or how advanced, mesothelioma is after discovering it. This is accomplished through conducting a CT scan, PET scan or other surgical diagnostic methods.

These tests allow doctors to see if the mesothelioma has spread beyond the point of origin. The spread of this cancer is known as mesothelioma metastasis and it’s important in the staging of mesothelioma.

The Basics of Mesothelioma Stages

The primary factor in mesothelioma stages is the level of metastasis. Mesothelioma forms primarily in one of two protective linings: the pleura (which separates the chest wall and lung cavity) or the peritoneum (which covers the abdominal cavity). The stages of mesothelioma advance as the cancer moves further from these original sites.

If you have mesothelioma, knowing the stage of your cancer is vital to determining your best treatment plan. The different mesothelioma stages provide boundaries for physicians as they recommend treatment options.

The stages of mesothelioma will impact your treatment options. You should always seek a second opinion, which may lead to a lower mesothelioma stage and more opportunities for treatment.

Pleural Mesothelioma Stages

Pleural mesothelioma stages are classified from Stage 1 to Stage 4. Stage 1 pleural mesothelioma is localized in the pleura. As the cancer spreads farther away from its point of origin, the pleural mesothelioma stages advance.

There are three staging systems used for pleural mesothelioma. The outline below will follow the Tumor, Node, Metastasis (TNM) Staging System.

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Stage 1 Pleural Mesothelioma

Stage 1 pleural mesothelioma is categorized by the lack of metastasis and lymph node involvement. The tumors are also small in collective size. This stage is divided into 1A and 1B.

Stage 1A involves mesothelioma cells only on the pleura’s outer cell layer (parietal). Stage 1B involves diseased cells on the inner cell wall (visceral) as well. Curative treatment options are available for Stage 1 pleural mesothelioma patients.

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Stage 1 Pleural Mesothelioma

The cancer is located on or in:

  • One side of the chest
  • The lining of the chest wall
  • The lining between the chest wall and lungs (pleura)
  • The lining of the diaphragm
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Stage 2 Pleural Mesothelioma

Stage 2 pleural mesothelioma involves the cancer spreading beyond the pleura. The cancer is still localized to one side of the chest.

The mesothelioma tumors continue growing and replicating during this stage and often begin invading the lung cavity. The tumors also begin spreading toward the chest wall, which is known as diffuse chest wall invasion. Treatment options for this pleural mesothelioma stage still include the curative surgeries.

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Stage 2 Pleural Mesothelioma

The cancer has spread to:

  • The surrounding lung tissue
  • Partial areas on the diaphragm
  • Lymph nodes (possibly)
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Stage 3 Pleural Mesothelioma

Stage 3 pleural mesothelioma hasn’t spread to the other side of the chest, but there is definite metastasis to the lymph nodes. Stage 3 is more locally aggressive, meaning it has affected the nearby lung and may have also spread to other organs. Curative surgery is not always a treatment option for Stage 3 pleural mesothelioma patients.

Similar to Stage 1, this stage is split into 3A and 3B. The TNM system differentiates the two by how far the cancer has spread. While still considered localized metastasis, stage 3B often is more challenging to treat with surgery.

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Stage 3 Pleural Mesothelioma

The cancer has likely spread to the surrounding tissue, such as:

  • Tissue between the ribs and lining of the chest wall
  • Fat in the area between the lungs
  • Soft tissue in the chest wall (not just the lining)
  • The sac surrounding the heart (pericardium)

Similar to Stage 1, this stage is split into 3A and 3B. The TNM system differentiates the two by how far the cancer has spread. While still considered localized metastasis, stage 3B often is more challenging to treat with surgery.

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Stage 4 Pleural Mesothelioma

Stage 4 pleural mesothelioma is the most advanced stage of this cancer and involves distant metastasis. Patients may experience more serious symptoms, such as difficulty swallowing and coughing up blood.

Treatment options are limited due to how far the cancer has spread — and how difficult or harmful it is to remove tumors through surgery. The main treatment options for stage 4 patients are chemotherapy, radiation and pain-relief operations (such as draining fluid).

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Stage 4 Pleural Mesothelioma

In this stage, the cancer has likely metastasized to the:

  • Lymphatic system
  • Opposite sides of the chest, diaphragm and peritoneum
  • Spine and distant organs
  • All organs within the chest cavity

Peritoneal Mesothelioma Stages

Peritoneal mesothelioma staging involves a different system than the four-stages one for pleural mesothelioma. Peritoneal mesothelioma rarely involves metastasis to lymph nodes, so doctors don’t rely on that characteristic for staging. They instead look at the extent of the tumors in the abdominal cavity and follow the peritoneal cancer index (PCI).

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What Is the Peritoneal Cancer Index?

The peritoneal cancer index is the primary staging system for peritoneal mesothelioma. It applies a score based on how far the cancer has spread within the abdomen.

13 Sections of the Abominal Cavity

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The PCI scores on a range of 0-39, with each of the 13 sections of the abdomen receiving a score between 0 and 3. If a section has no signs of mesothelioma, it receives a 0 score. If the section is overrun with mesothelioma tumors, then it receives a 3.

Some doctors simplify the PCI for patients’ understanding by correlating a score to one of the four pleural mesothelioma stages:

PCI OF 1-10

STAGE 1

PCI OF 11-20

STAGE 2

PCI OF 21-30

STAGE 3

PCI OF 31-39

STAGE 4

The lower the PCI score, the more treatment options are available. However, you should always receive a second opinion after your initial diagnosis.

Mesothelioma survivor Alexis K. was originally diagnosed with late-stage peritoneal mesothelioma. Her cancer was considered inoperable. A second opinion revealed a less-advanced stage. Alexis underwent curative surgery and as of 2020, she has survived for 12 years and counting.

Staging Systems

The three common systems used for staging pleural mesothelioma are the TNM, Butchart and Brigham. The primary staging system for peritoneal mesothelioma is the peritoneal cancer index.

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Mesothelioma TNM Staging

The mesothelioma TNM Staging System is the most commonly used system. It is a four-stage system developed by the American Joint Committee on Cancer (AJCC) and the International Union for Cancer Control (IUCC).

It evaluates three aspects of the cancer: the tumors’ size (T), lymph node involvement (N) and metastasis (M). Each aspect receives a classification to help doctors stage the disease.

THE T CATEGORY

The T category considers whether mesothelioma tumors have grown within the pleural space and invaded nearby tissue:

  • TX means the tumors cannot be measured.
  • T0 means the tumors can’t be found.
  • T1, T2, T3 and T4 measure the tumors’ collective size and where the cancer has spread.

THE N CATEGORY

The N category focuses on lymph nodes:

  • NX means lymph node involvement can’t be evaluated.
  • N0 means there is no lymph node involvement.
  • N1, N2 and N3 are classifications when lymph node involvement occurs, with numbers ranging in how many are affected and how much they’ve swollen.

THE M CATEGORY

The M category focuses on metastasis to other areas of the body:

  • M0 means no metastasis has occurred (the disease remains local).
  • M1 means the mesothelioma has spread to distant organs or tissues.

The AJCC and IUCC update the mesothelioma TNM Staging protocol every six or eight years as cancer research and treatment evolves. The system was last updated in 2018 to include Stage 1A and Stage 1B.

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The Butchart System

Developed by Dr. Eric Butchart in 1976, the Butchart System is the oldest system for determining mesothelioma stages. It consists of four stages and focuses on the size of the tumors, rather than the number of cancer cells and tumors that have formed, or where they’ve spread.

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The Brigham System

Dr. David Sugarbaker, who passed away in 2018, developed the Brigham Staging System while working at Brigham and Women’s Hospital in Boston. This system focuses on whether surgery is an option for the patient. It is a four-stage system that looks at whether there is lymph node involvement.

The system considers location, size and spread of the cancer. Stage 1 and Stage 2 patients are candidates for surgery. Stage 3 and Stage 4 patients are not.

What Is the Next Step After Mesothelioma Staging?

Once mesothelioma staging concludes, patients should review their treatment options with their primary doctor. Depending on your mesothelioma stage, you may be eligible for life-saving surgery.

If you have a mesothelioma stage that prevents you from receiving curative treatment, then you should consider getting a second opinion from a mesothelioma specialist. Second opinions for your mesothelioma stage may provide new treatment options to extend life. Get connected to a specialist today using our free Doctor Match program.

Last Edited: July 9, 2020.

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