Stage 3 Mesothelioma

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This page was medically reviewed by James Stevenson, M.D. on February 6, 2019. For information on our content creation and review process read our editorial guidelines. If you notice an error or have comments or questions on our content please contact us.

James Stevenson, M.D. Thoracic Medical Oncologist

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In Stage 3 mesothelioma, the cancer has spread to nearby tissues, organs and possibly to distant lymph nodes. Stage 3 is the most frequently diagnosed stage of mesothelioma with a median life expectancy of about 16 months.

Symptoms increase in severity for stage 3 malignant mesothelioma patients as the cancer progresses. Although there is no spreading to distant organs and tissues, nearby spreading and lymph node involvement typically limits treatments available, as aggressive surgery is typically not an option.

01. Overview

Stage 3 Mesothelioma by Type

During the diagnostic process, physicians will look at a patient’s medical history and symptoms, conduct imaging tests and blood tests, as well as a biopsy, to determine cancer type and staging. Mesothelioma cancer uses a four-tier staging system to classify the disease, and staging varies based on the type of mesothelioma that a patient has.

Stage 3 Pleural Mesothelioma

Pleural mesothelioma is the most commonly diagnosed type of the cancer, making up 80 – 90% of all diagnoses. Specialists have established three staging systems for this type, including the Brigham system, Butchart system and TNM system, which is the most common.

The TNM system looks at the size and extent of mesothelioma tumors (T), lymph node involvement (N) and metastasis (M), or growth. Stage 3 malignant pleural mesothelioma is classified further into stage 3A and stage 3B.

Stage 3A Mesothelioma
  • Cancerous cells are present in the pleura on one side of the chest
  • Nearby lymph node involvement
  • Potential spreading into chest wall, pericardium, fascia lining or mediastinal fat
  • No distant metastasis
Stage 3B Mesothelioma
  • All components of stage 3A mesothelioma with distant lymph node involvement possible


  • Spreading into chest wall, peritoneum, pleura on opposite side of the chest, mediastinal organs, pericardium or other areas of the spine
  • Nearby or distant lymph node involvement
  • No distant metastasis

The defining characteristic between stage 3 and stage 4 mesothelioma is that stage 3 diagnoses have spreading into nearby organs and tissues, while stage 4 diagnoses indicate metastasis to distant organs and tissues. According to the American Cancer Society, the 2-year survival rate for stage 3 mesothelioma is around 26 – 30% and the 5-year survival rate is around 5 – 8%.

Stage 3 Peritoneal Mesothelioma

Malignant peritoneal mesothelioma makes up just 15 – 20% of all diagnoses. Less common than pleural mesothelioma, this type doesn’t have its own staging system. Instead, mesothelioma specialists use general mesothelioma characteristics or the Peritoneal Cancer Index (PCI), which grades tumors throughout distinct areas of the abdomen and totals the scores together. A score ranging from 21 – 30 indicates stage 3 peritoneal mesothelioma.

Mesothelioma tumors are localized to the abdomen at this stage, but may have spread to nearby organs and lymph nodes. Many stage 3 peritoneal mesothelioma cases show cancer growth in the chest wall and throughout the abdominal cavity.

Stage 3 Pericardial Mesothelioma

Pericardial mesothelioma makes up only 1 – 2% of diagnoses. With limited case studies, specialists have not established a pericardial mesothelioma staging system. Pericardial mesothelioma tumors are often aggressive and fast-growing, and most patients are diagnosed at stage 3 or stage 4, or posthumously during an autopsy. At this stage, the cancer has likely spread throughout the chest cavity and to nearby organs and lymph nodes and possibly the lungs.

Stage 3 Testicular Mesothelioma

Even rarer than pericardial mesothelioma, testicular mesothelioma also does not have a definitive staging system, and specialists rely on general staging tools to diagnose the disease. Stage 3 testicular mesothelioma indicates that the cancer has spread outside of the linings of the testicles, limiting treatment options and worsening prognosis.

02. Symptoms

Stage 3 Mesothelioma Symptoms

In earlier stages, mesothelioma symptoms are often minor and may not even be noticeable. But by stage 3, symptoms are more intense and may be severe. Stage 3 patients often undergo various palliative treatments to relieve symptoms, which could involve procedures like pleurocentesis or pleurodesis to remove fluid buildup, alleviating pain and improving breathing.

Common Symptoms of Stage 3 Mesothelioma
  • Chest or abdominal pain
  • Chest tightness
  • Coughing
  • Difficulty breathing
  • Fatigue
  • Fever
  • Fluid buildup
  • Shortness of breath (dyspnea)
  • Weight loss

Even if cancer has progressed to stage 3, it’s still crucial for patients to get medical care as soon as possible to begin treatment before the disease progresses further.

03. Prognosis

Prognosis of Stage 3 Mesothelioma

Stage 3 malignant mesothelioma patients face an average life expectancy of 16 months. Prognosis is less favorable than early stages because the disease has become more invasive, and aggressive surgical treatments are typically no longer an option.

Prognosis will vary from patient to patient as each diagnosis is different. Patient gender, age, genetics, overall health and history of smoking can impact prognosis, as well as cell type and cancer type. Survival rates continue to increase as researchers and mesothelioma doctors improve diagnostic tools and discover new treatment techniques.

04. Treatment

Stage 3 Mesothelioma Treatment

Staging is an influential factor in determining a patient’s treatment plan. Stage 3 patients usually have limited options and aren’t able to undergo aggressive surgeries or multimodal treatment.

Surgery, chemotherapy and radiation may be used on their own to remove as much cancer as possible or delay cancer progression. These therapies may also be applied palliatively to relieve symptoms. Palliative care is often a large component of stage 3 treatment plan to provide the patient with the highest quality of life possible.

  • Surgery: Pleurodesis, paracentesis or thoracentesis are palliative surgeries that may be used to remove fluid buildup.
  • Chemotherapy: Hyperthermic intraperitoneal chemotherapy (HIPEC) has shown success in extending life expectancies by at least 50% in some peritoneal mesothelioma cases, but may be too aggressive for patients with advanced spreading. Intravenous chemotherapy options such as pemetrexed, cisplatin and bevacizumab are used to prolong life and improve quality of life. Immunotherapy treatments have also become standard options after chemotherapy.
  • Radiation: Radiation therapy may be used palliatively to shrink tumors and reduce symptoms like chest pain and difficulty breathing.

Staging is an important factor in determining what treatments a patient can pursue. Accurate staging not only helps physicians understand disease progression, but can also provide patients with insight into their treatment options.

Patients may be eligible for experimental cancer treatments and clinical trials that have shown success in improving life expectancy in some cases. Patients should discuss options with their physician to see if they meet the criteria required to participate in such treatments.

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