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Stage 3 Mesothelioma

The stage of cancer refers to how advanced the cancer is in the body. Stage 3 is considered a more advanced stage of cancer. In stage 3 mesothelioma, the cancer has spread to lymph nodes beyond the local area but has not spread to more organs. Treatment is available for patients with stage 3 mesothelioma; surgery may or may not be an option.


Medically Reviewed By:
Patricia Shelton, M.D.

Patricia Shelton

Medically Reviewed By:Patricia Shelton, M.D.

Stage 3 is generally considered to be a more advanced stage of cancer. Some patients in stage 3 may be eligible for tumor-removing surgery, but most will not. However, patients still have treatment options that can extend survival.

What is Stage 3 Mesothelioma?

Cancer is most commonly described using a system of four stages. Stage 1 is the earliest stage, while stage 4 is the most advanced. A few different factors are used to determine the stage, including the size and extent of the original tumor and whether it has spread to lymph nodes or to more distant organs.

Stage 3 cancers may have a variety of different characteristics. In general, cancers in stage 3 may have spread to lymph nodes beyond the immediate local area, and/or they may have undergone more extensive local spread. However, stage 3 cancers have not spread to more distant organs of the body.

Stage 3 Pleural Mesothelioma

Pleural mesothelioma is the only type of mesothelioma that has a formal staging system. This system has been officially accepted by the American Joint Committee on Cancer. The most recent updates were published in 2016 and officially accepted in 2018. Using the newest version of the system, stage 3 pleural mesothelioma is divided into two substages:

  • In stage 3A, there is spread to lymph nodes on the same side of the chest only. The tumor has also grown to involve the chest wall, the pericardium (the membrane around the heart) and/or the mediastinum (the tissue in the center of the chest). 
  • In stage 3B, there is spread to lymph nodes on the opposite side of the chest. The tumor may involve only the pleura, or it may involve the lung, diaphragm, chest wall, pericardium and or mediastinum. 

If the tumor has only spread to the lung or the diaphragm, and lymph nodes are involved only on the same side of the chest, then the cancer is in stage 2. If the cancer has spread more extensively into other organs of the chest (such as the heart, spine or ribs), then it will be diagnosed as stage 4. Any spread to more distant parts of the body also places the cancer in stage 4.


Stage 3 Peritoneal Mesothelioma

There is no formally defined staging system for peritoneal mesothelioma, and doctors may use a few different methods for determining the stage of a particular case. 

One common system is called the modified TNM staging system. This system uses only three stages for peritoneal mesothelioma; this is somewhat unusual, as most cancer staging systems have four stages. Using the modified TNM system, peritoneal mesothelioma patients are considered to be in stage 3 if they have one or more of the following:

  • Very extensive local spread within the abdomen. The peritoneal cancer index (PCI) is used to quantify the extent of spread. The abdomen is divided into 13 sections, and the amount of cancer tissue in each one is scored from 0 to 3. Patients with a PCI of 31 or higher are in stage 3.
  • Spread to lymph nodes, and/or metastases to more distant organs outside of the abdominal cavity.

The modified TNM system is gaining more widespread acceptance but is not the official system for determining the stage of peritoneal mesothelioma. Some doctors may use alternative ways of describing a patient’s stage. In many types of cancer, a patient would be considered to be in stage 3 if there is relatively extensive local disease and/or spread to lymph nodes, particularly those that are beyond the immediate local area. However, any metastasis to other parts of the body would place a cancer in stage 4.

Diagnosis of Stage 3 Mesothelioma

The clinical stage of a cancer is the stage as determined by information obtained before surgery. This may include the results of a few different types of tests, including:

Imaging studies, which can allow doctors to localize the primary tumor and look for more distant spread of the cancer.

    • Computerized tomography scans (CT scans) and/or magnetic resonance imaging (MRI) are detailed scans that can allow doctors to precisely determine the extent of the primary tumor. In patients with stage 3 mesothelioma, these types of scans may show enlarged lymph nodes in certain areas, which suggests that cancer has spread to those nodes. Doctors can also look for evidence of metastasis; if found, this would generally place the cancer in stage 4 rather than stage 3. (However, under the modified TNM system, metastatic peritoneal mesothelioma is stage 3.)

Biopsy results. On a biopsy of the original tumor, pathologists will look for signs such as the cancer cells passing through certain membranes, which indicates that the cancer has begun to spread. Biopsies of lymph nodes can be used to determine whether cancer cells are present in them; if so, this places the cancer in stage 2 or 3.

There are some cases where the stage of a cancer changes as a result of information discovered during surgery. The new stage is known as the pathological stage. For example, based on clinical evidence, a patient may be believed to have stage 1 pleural mesothelioma, without spread to lymph nodes or more distant organs. However, during surgery to remove the cancer, lymph nodes will be biopsied and the samples sent to a pathologist. If cancer is detected in any of these samples, then the cancer may be restaged as stage 2 or 3. When the stage of a cancer increases based on information discovered during surgery, this is called upstaging.

Upstaging has been found to occur in up to 80 percent of early stage (stage 1 and 2) pleural mesothelioma patients, who may then be reclassified to stage 3 or 4 after surgery. It also occurs in 22.8 percent of patients in clinical stage 3, who may then be reclassified to stage 4.

Stage 3 Mesothelioma Life Expectancy

For patients with stage 3 pleural mesothelioma, studies have reported an average life expectancy of about 16 months. Only approximately 10 percent of pleural mesothelioma patients survive for five years after diagnosis.

In general, the prognosis for peritoneal mesothelioma is better than for pleural mesothelioma. Peritoneal mesothelioma patients who are in stage 3 by the modified TNM system have a five-year survival rate of 29 percent.

Treatment for Stage 3 Mesothelioma

Treatment options for patients with stage 3 mesothelioma can vary widely. Stage 3 mesothelioma may be considered resectable in some cases, meaning that patients may be candidates for surgery. However, there are also patients in this stage who are no longer eligible for surgery.

Stage 3 Pleural Mesothelioma Treatment Options

For patients whose cancers are considered resectable, surgery is generally the preferred treatment option. This is generally used along with other treatment modalities to remove as much of the cancer as possible. The treatment plan may include:

Tumor-removing surgery, which is intended to remove as much cancer tissue as possible. Surgical options may include extrapleural pneumonectomy (EPP), in which the lung, pleura and other tissues are removed on the affected side, or pleurectomy/decortication (P/D), which leaves the lung in place but removes the pleura along with as much tumor tissue as possible.

Radiation therapy, which may be given after surgery to reduce the chances of the tumor growing back.

Chemotherapy, which may be combined with surgery in a number of different ways:

  • Intraoperative chemotherapy, also known as hyperthermic intrathoracic chemotherapy (HITHOC). After removing as much tumor tissue as possible, the surgeon infuses a warmed solution of chemotherapy drugs into the thoracic cavity. This is left in place for a period of time and then washed out before the surgical incisions are closed.
  • Adjuvant chemotherapy, which is used after surgery to target cancer cells that may have been left behind.
  • Neoadjuvant chemotherapy, which is used before surgery to shrink the tumor and make it easier to remove.

There are also some stage 3 pleural mesothelioma patients whose cancers are not considered resectable. These patients still have effective treatment options available, including:

Systemic chemotherapy, which is delivered to the whole body through an IV. Patients often receive a combination of chemotherapy medications in order to increase effectiveness.

Immunotherapy. These medications stimulate the immune system to target and destroy the cancer cells. Two different types of immunotherapy are FDA-approved to treat certain cases of unresectable pleural mesothelioma.

Tumor-treating fields. This device applies an alternating electrical current through the skin to make it harder for cancer cells to divide and grow. It is sometimes used along with chemotherapy.

Clinical trials, which are research studies of new treatment modalities. Some patients choose to participate in hopes of getting early access to a new treatment that might extend their lives.

Palliative treatment options, which can include:

  • Thoracentesis, which drains fluid from around the lungs in order to relieve symptoms like shortness of breath.
  • Pleurodesis, in which a doctor inserts a medication between the two layers of the pleura to cause them to adhere to each other, so fluid can’t build up between them.
  • Surgery and/or radiation therapy to target specific tumors that are causing significant symptoms.
  • Medications and physical therapy to help manage symptoms.

Stage 3 Peritoneal Mesothelioma Treatment Options

When the modified TNM system is used to determine the stage, then patients with stage 3 peritoneal mesothelioma may or may not be candidates for a procedure called CRS-HIPEC, which has been shown to be highly effective in treating this disease. 

Cytoreductive surgery (CRS) involves a surgical procedure to remove as much tumor tissue as possible from the abdomen.

Hyperthermic intraperitoneal chemotherapy (HIPEC) involves infusing a warmed solution of chemotherapy medications into the abdominal cavity after the removal of tumor tissue. This targets any cancer cells that have been left behind.

Patients who are in stage 3 because their disease has spread extensively through the abdomen (resulting in a PCI of 31 or higher), but who have not yet had spread to lymph nodes or more distant organs, may still be candidates for CRS-HIPEC. However, those whose cancer has already spread outside of the abdominal cavity are not good candidates for the procedure. For these patients, the treatment plan may include:

Systemic chemotherapy, which is delivered to the whole body through an IV. Often, multiple different chemotherapy medications are given.

Clinical trials, which are research studies to test new treatment methods. Some patients choose to participate in hopes of getting early access to a new method of treating their cancer.

Palliative treatments, which may include: 

  • Paracentesis, which can be used to drain fluid from the abdominal cavity. 
  • Radiation therapy or surgery to target particular tumors that are causing symptoms.
  • Medications or physical therapy to help relieve symptoms.
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