Straight Talk about Mesothelioma, a blog series created by Michael T. Milano, M.D., Ph.D., a radiation oncology specialist, as a resource for mesothelioma patients and their loved ones.

If you or a loved one has been diagnosed with malignant mesothelioma, it’s understandable that there’s not a whole lot that can be said to console you. Patients and their families are swarmed with stress and confusion about how and why such a disease has infiltrated their lives.

While the prognosis for mesothelioma is generally poor (it’s a terminal cancer), there are a lot of factors that directly influence how long a patient may live after being diagnosed. These details are heavily considered by doctors, not only in determining a patient’s life expectancy, but also in developing a treatment plan. Nonetheless, all decisions a doctor makes are made with the goal of extending the patient’s life as much as physically possible.

For example, a middle-aged patient (40 – 55) with an otherwise clean health record will likely survive longer than a senior citizen who has difficulty doing day-to-day activities without becoming tired or winded. Nevertheless, the most important factors in determining a patient’s life expectancy are the type and stage of the cancer.

Cancer Staging: An Introduction

Doctors use staging systems to determine the general extent and severity of a cancer. They assign a number – I to IV – with “I” indicating an isolated tumor and “IV” implying a cancer that has spread (metastasized) to other regions of the body. The later the stage, the more serious the prognosis.

Because it’s relatively rare and, therefore, lacking sufficient data to inform a diagnosis, peritoneal (abdominal) mesothelioma currently has no formal staging system. (Researchers are currently investigating a potential staging system.) Pleural mesothelioma, however, is diagnosed in a similar way to other cancers. In addition to the I-IV method described above, doctors also use something called the “TMN staging system.”

The “T,” “N,” and “M” stand for “tumor,” “node,” and “metastasis,” respectively, and they are combined with the numerical stage of a cancer to provide a more specific categorization of the condition (e.g., “T4” or “N1”).

Generally, the “T” or “tumor” designation refers to the size and spread of the main or original tumor. “N” or “node” determines if the cancer has spread to the lymph nodes, which itself indicates how the cancer is spreading through the body. Finally, “M” or “metastasis” implies whether the cancer has spread (or “metastasized”) to other areas or organs of the body.

How Is the Stage Determined?

Doctors perform a variety of physical examinations, biopsies, and imaging tests to determine both the numerical and TMN stage of a cancer. Some of these tests include x-rays, CT (computed tomography), MRI (magnetic resonance imaging), and PET (positron emission tomography) scans. Together, this information can be used to visually assess the extent of tumors. If the cancer is not clearly visible, doctors can use blood, fluid, and tissue tests to find evidence of cancer cells. For example, mesothelioma patients typically have higher levels of certain proteins that can be directly detected through a blood test.

Keep in mind, however, that the staging of any cancer — mesothelioma or otherwise — is not the only factor in determining a patient’s prognosis or life expectancy. Doctors also consider:

  • Age
  • Gender
  • Recent weight loss
  • Physical fitness
  • Red and white blood cell counts
  • The appearance of the cancer cells under a microscope (histopathology)

All of these factors affect survival times and are considered by doctors when predicting life expectancy.

Nevertheless, the 5-year survival rate for malignant mesothelioma (at any stage) is low (just 10 percent). The 1-year survival rate is also poor, at 40 percent. While those figures have improved significantly in recent decades, patients and their families are often encouraged to manage their expectations.