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Stage 1 Mesothelioma

Stage 1 mesothelioma is the earliest stage of the disease, indicating the tumor is confined to a specific area and has not yet spread to other parts of the body. At this stage, patients generally have the most treatment options available with the longest life expectancy. Though early detection is rare, those diagnosed at stage 1 typically live 21 months or longer.

Malignant mesothelioma is categorized using a four-tier staging system that indicates the severity and development of the disease. At stage 1, mesothelioma has begun to develop within the lining of the organ affected, but has not yet invaded nearby tissues or spread to lymph nodes or other organs. Symptoms are minimal and are often confused with symptoms of other diseases, leading to misdiagnosis and delays in diagnosis.

Stage I Mesothelioma Illustration Lungs Icon

Stage 1 Mesothelioma by Type

Patients diagnosed with pleural, peritoneal, pericardial or testicular mesothelioma at stage 1 have the most treatment options available compared to the later stages. At this stage, the disease is localized without spreading, and is, therefore, easier to target and treat with surgery, chemotherapy and radiation therapy.

Stage 1 Pleural Mesothelioma

Mesothelioma specialists use three different staging systems to categorize malignant pleural mesothelioma, including the Butchart system, Brigham system and TNM system. Staging for all three systems is similar, though the TNM system is most common and updated with the most recent information on mesothelioma. This option focuses on tumor sizing and extent, number of affected lymph nodes and metastasis. Unlike the other staging systems, the TNM system classifies stage 1 mesothelioma even further into stage 1A and stage 1B pleural mesothelioma.

Stage 1A Mesothelioma

  • Cancerous cells are in the pleural lining of the chest wall, on just one side.
  • No metastasis to distant organs or the lymph nodes

Stage 1B Mesothelioma

  • Cancerous cells are in the pleural lining of the chest wall, on just one side.
  • Tumor growth may extend into the lung tissues, diaphragm, chest wall, pericardium, mediastinal fat or fascia layer.
  • No metastasis to distant organs or the lymph nodes

Resources for Stage 1 Mesothelioma Patients

For stage 1A malignant pleural mesothelioma, the 2-year survival rate is around 46%, and the 5-year survival rate is around 16%. In comparison, stage 2 malignant pleural mesothelioma has a 2-year survival rate of around 38% and a 5-year survival rate of around 10%. These survival rates decrease even further for stage 3 and stage 4.

Stage 1 Peritoneal Mesothelioma

Due to a limited number of peritoneal mesothelioma cases, there isn’t a specific staging system for this type. Specialists rely on the Peritoneal Cancer Index (PCI) for peritoneal mesothelioma staging, which scores the size and number of tumors throughout the abdominal region and adds them together for a numerical total. This total is then used to determine the stage. A score between one and 10 indicates stage 1 peritoneal mesothelioma, indicating minimal tumor extent.

Stage 1 Pericardial Mesothelioma

Accounting for only 1 – 2% of all mesothelioma diagnoses, pericardial mesothelioma does not have a definitive staging system. This type is particularly aggressive with severe symptoms, and as a result, is typically not caught in the early stages. A stage 1 diagnosis would be considered if the mesothelioma is localized within the pericardium (heart linings) and have not spread to distant organs or to the lymph nodes.

Stage 1 Testicular Mesothelioma

Like pericardial mesothelioma, testicular mesothelioma is extremely rare, accounting for only 1% of all cases. There is no definitive staging system used, though a stage 1 diagnosis would be considered if the cancerous cells are limited to the tunica vaginalis (testicle linings) and no distant metastasis or spreading to the lymph nodes.

Stage 1 Mesothelioma Symptoms

Symptoms of mesothelioma may be minimal at stage 1, oftentimes going unnoticed or misdiagnosed for minor conditions like a cold or the flu. If any concerning symptoms occur, patients should seek medical attention right away, as early detection can extend life expectancy and allow a broader range of treatment options.

Common Symptoms of Stage 1 Mesothelioma
  • Shortness of breath
  • Chest pain
  • Coughing
  • Fever
  • Fatigue

Prognosis for Stage 1 Mesothelioma

The prognosis for stage 1 mesothelioma is the most favorable of the stages, giving patients higher survival rates than advanced stage diagnoses. Patients typically live 21 months or longer, but prognosis can vary based on location of the tumors, cell type and patient health.

During stage 1, symptoms may be mild and patients are generally still in good overall health, allowing them to receive aggressive treatments. Tumors are also localized, allowing for aggressive surgery and multimodal treatments. As mesothelioma nears the later stages, treatments become more limited and patients may be more likely to experience the side effects of chemotherapy and radiation.

Stage 1 Mesothelioma Treatment

Stage 1 has the most treatment options available of the four mesothelioma stages, and each of the standard treatments can be applied more aggressively for this stage than the later stages. Typically, patients undergo a multimodal treatment plan, which is a combination of surgery, chemotherapy and radiation.

Treatment plans for stage 1 mesothelioma patients may include:

Aside from traditional treatment plans, many stage 1 mesothelioma patients may seek clinical trials for experimental treatments like immunotherapy and targeted therapies, which have shown promise. While palliative treatments are common for late-stage diagnoses, they may also be used for stage 1 patients to reduce cancer symptoms and provide patients with comfort through their treatment journey.

Author: Linda Molinari

Editor in Chief, Mesothelioma Cancer Alliance

Linda Molinari

Reviewer: Dr. James Stevenson

Medical Reviewer and Thoracic Medical Oncologist

Dr. James Stevenson

Alexander HR Jr., Li CY and Kennedy TJ. Current Management and Future Opportunities for Peritoneal Metastases: Peritoneal Mesothelioma. Annals of Surgical Oncology. August 2018; 25(8):2159-2164.

American Cancer Society. Survival Statistics for Mesothelioma. Updated December 2017.

Bonomi M, De Filippis C, Lopci E, et al. Clinical staging of malignant pleural mesothelioma: current perspectives. Lung Cancer. August 2017; 8:127-139. doi: 10.2147/LCTT.S102113

Chekol SS and Sun CC. Malignant Mesothelioma of the Tunica Vaginalis Testis: Diagnostic Studies and Differential Diagnosis. Archives of Pathology & Laboratory Medicine. January 2012; 136(1):113-117. doi: 10.5858/arpa.2010-0550-RS

International Association for the Study of Lung Cancer. 8th Edition of the TNM Classification for Malignant Pleural Mesothelioma.

Karpathiou G, Mobarki M, et al. Pericardial and Pleural Metastases: Clinical, Histological and Molecular Differences. The Annals of Thoracic Surgery. September 2018;106(3)872-879. doi: 10.1016/j.athoracsur.2018.04.073

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