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What stage 3 mesothelioma looks like inside the body.

What Is Stage 3 Mesothelioma?

Stage 3 mesothelioma is the second to last stage characterized by cancer cells and tumors spreading throughout the abdomen and chest cavity. People diagnosed with stage 3 have reached an advanced level of infection and their symptoms are hard to ignore because they are beginning to interfere with daily activities. Most people diagnosed with mesothelioma are in stage 3 since stages 1 and 2 typically do not have prominent symptoms.

Symptoms of prolonged chest pain and discomfort may lead to your doctor ordering a chest X-ray to examine your lungs and chest further. Mesothelioma on a chest X-ray may show irregularities such as fluid buildup, pleural thickening, or tumors. After viewing your chest X-ray, your doctor may have you undergo further imaging scans like a CT, MRI, or PET scan to solidify your diagnosis.

Mesothelioma is diagnosed with two staging systems— SEER stages and TNM staging. The SEER, or surveillance, epidemiology, and end results, database compiles survival statistics based on their data research into a disease. They stage cancer by separating them into localized, regional, and distant groups, which is based on where the cancer has spread to.

The TNM staging system is broadly used to stage many cancers accurately. It decides which stage your in depending on the size and extent of your tumors, the number of lymph nodes with cancer, and whether your cancer has metastasized. When you seek a medical center for help for mesothelioma, you will likely be advised which stage of cancer you are in with the TNM stages.

Stage 3 Life Expectancy and Treatment by Mesothelioma Type

By the time a patient has reached stage 3 their odds of surviving long-term have decreased significantly. Since cancer has spread beyond the initial area of infection, treatment options have become minimal. A stage 3 mesothelioma prognosis is around 16 months. This number can vary depending on which type of mesothelioma you have.

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

Stage III Pleural Mesothelioma

If you have been diagnosed with mesothelioma, odds are you probably have it in your pleura. Pleural mesothelioma accounts for 70% and 90% of all disease cases. It affects the pleura, the lining of the lungs and chest, and is the only type with a defined staging system.

Tumors in this stage have grown into nearby tissues and organs and have begun to infect their functioning abilities. Surgery is typically reserved for localized tumors, but depending on the cancer’s progression it may still be an option. Cancer cells have likely reached the lymph nodes, diaphragm, and potentially the heart sac but remain localized to these areas. There is no further spreading of tumors into other organs at this stage.

The TNM scale has two categories for stage 3 pleural mesothelioma. Stage 3A and Stage 3B have overlapping characteristics but distinct differences to allow for accurate disease staging.

Stage 3A

  • Primary tumor is likely resectable
  • Cancer is localized to one side of the chest cavity and may reach the lymph nodes or diaphragm
  • Cancer may have reached the pericardium (heart sac)
  • Tumors have not spread beyond the abdomen areas

Stage 3B

  • Metastasis may be too extensive for surgery
  • Cancer may be more expansive, getting into the abdomen or other nearby organs
  • Lymph nodes are infected, creating a higher likelihood of spreading throughout the body
  • Other vital organs remain uninfected


This is an image of stage 3 peritoneal mesothelioma.

Stage III Peritoneal Mesothelioma

Cancer formed in the abdomen is peritoneal mesothelioma. This form is rare, accounting for only about 660 cases annually. There hasn’t been a staging system yet because of the very small amount of data to collect.

Instead, doctors look to the Peritoneal Cancer Index (PCI) for staging peritoneal mesothelioma. The PCI measures the extent of metastasis and provides a score between 0 and 39. A low score represents a less aggressive cancer, whereas a high score indicates a large amount of cancer. Stage 3 patients usually have a PCI score between 21 to 30. After a PCI score is determined, doctors can determine a patient’s course of treatment.

The PCI score helps doctors determine a patient’s course of treatment.


This is an image of stage 3 pericardial mesothelioma.

Stage III Pericardial Mesothelioma

Pericardial mesothelioma is the second-rarest form of this disease. It typically accounts for less than 5 percent of all cases annually. This form of mesothelioma forms in the lining of the heart and has a high mortality rate. Doctors seeking to diagnose this form typically use the American Joint Committee on Cancer (AJCC) 1 through 4 staging scale. This staging system is similar to the TNM stages as they look into the location and size of the tumor, lymph node involvement, and check for metastasis.

Stage III Testicular Mesothelioma

Testicular mesothelioma is the rarest form of mesothelioma, with barely 100 cases documented. With very few cases to study, there isn’t much data to support the accuracy of survival rates, prognosis, or treatment options available. It is known that this form of cancer forms in the lining of the testicles. Almost 50% of people diagnosed with it may survive up to 5 years after diagnosis.

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What are the Symptoms of Stage III?

Early-stage symptoms of mesothelioma are often overlooked as they can mimic the common cold or flu. Fever, headache, and body aches are common stage 1 and 2 symptoms, but they can also be seen in stage 3. As cancer grows, symptoms begin to become severe causing once-simple daily tasks to become hard to perform. It is common for a physician to diagnose you in stage 3 with increasing severity of symptoms. Stage 3 mesothelioma symptoms may include:

  • A persistent dry cough
  • Anemia
  • Blood clots
  • Body aches
  • Coughing up blood (hemoptysis)
  • Difficulty breathing
  • Fatigue
  • Fever
  • Fluid buildup in the chest or abdominal cavities
  • Night sweats
  • Severe chest or abdominal pain
  • Shortness of breath (dyspnea)
  • Unexplained weight loss

If you or a loved one are experiencing any of the above symptoms — especially if there is a work history around asbestos  — visit a doctor right away.

Stage 3 Mesothelioma Survival Rate by Age

The life expectancy for stage 3 mesothelioma patients is approximately 16 months. However, every case is different and a person’s age can be a contributing factor to your prognosis. It’s important to stay hopeful and remember that many patients have exceeded their initial predictions.

Other factors like gender, health, mesothelioma cell type, tumor location, social demographic, and more can impact a person’s survival rate. Each of these can lower or lengthen your chances of survival.

Treating a Late Stage Diagnosis

Without a cure, the treatment of mesothelioma is performed to help slow the rate of tumor growth and potentially reverse a diagnosis. For stage 3 mesothelioma, the extent of metastasis plays a defining role in determining a patient’s treatment plan. When the tumors are still potentially removable, doctors may treat cancer with surgery. After surgery, chemotherapy and radiation may be used to kill the remaining cancer cells left. Both therapies are commonly used to shrink tumors and prevent the proliferation of new ones.

Depending on your doctor’s advice, Immunotherapy could also be an option at this stage. This form of treatment boosts the body’s immune system in an effort to fight off and prevent the spread of cancer cells. Immunotherapy works because doctors are using the body’s capabilities to fight off disease and boost it through biological therapy. This treatment is continually being explored through clinical trials and may be available to test emerging treatments on stage 3 patients.

Patients who are looking to take the path of not treating their cancer and focusing on pain management may try palliative care. This form of care aims to treat symptoms and lessen the pain of individuals fighting mesothelioma. Radiation, chemotherapy, steroids, pain medicine, and more can all be considered forms of palliative care.

How Long can you Live With Stage 3 Mesothelioma?

Doctors may give those with stage 3 mesothelioma a 50% chance of living one year after their initial diagnosis. Again, other factors must be considered when determining an individual’s chance of surviving cancer. Whether or not you are seeking active treatment is one important deciding factor. Most treatment for mesothelioma is used to prolong an individual’s life since there isn’t a cure yet.

What treatment you seek may depend on what stage your in, where the cancer is, and if your body is reacting positively to the treatment. Although there can be a general chance of survival of 50% for stage 3, it is difficult to say every person will live up to this. Contacting your physician to seek their medical opinion for your specific case is important in determining you chances of survival.

Mesothelioma Support Team

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