After a diagnosis of mesothelioma, one of the next steps is determining the disease’s stage. Like most other cancers, mesothelioma has a staging system that helps doctors identify how far the disease has spread. There are four mesothelioma stages, with stage 1 having the best prognosis and stage 4 having the worst.
Only pleural mesothelioma has a clinically-accepted standard of staging, mainly because it is the most common form of the disease. The International Mesothelioma Interest Group (IMIG) and American Joint Committee on Cancer (AJCC) have approved a specific staging system for that type of the disease.
The other forms of mesothelioma (peritoneal, pericardial, and testicular) follow that method for staging in a general sense. The AJCC also has a staging method that applies to a number of different cancer varieties.
It really depends on the individual doctor and pathologist to help determine the stage of mesothelioma for these less known forms of the disease.
How Are Stages Determined for Mesothelioma?
It can take some time between the initial onset of symptoms and the determination of the disease’s stage. This is partly because mesothelioma in all its forms is a rare type of cancer that most doctors aren’t expressly looking for. Its symptoms can mimic a wide variety of more common cancer types like lung cancer, adenocarcinoma, and ovarian cancer.
Because of this, the process to diagnose mesothelioma may take some time.
Diagnosis for mesothelioma often requires the use of three primary methods:
- Imaging techniques (X-ray, MRI, CT-Scan, and PET scan)
- Blood tests and biomarkers
Imaging techniques are usually the first diagnostic procedures performed by doctors. In the early parts of the diagnostic process, staging is not a concern. Doctors are usually just looking to see if the imaging scans can identify the presence of any kind of mass or disease. Once the presence of mesothelioma has been verified, however, imaging scans can play a role in classifying the stage.
Most scans can detect where the disease is located and how far it may have spread.
Another diagnostic tool your doctor may use is a set of blood tests. Blood tests are performed to identify any biomarkers in the bloodstream. Biomarkers are substances in the blood that can indicate the presence of a disease. Most biomarkers for mesothelioma are glycoproteins like mesothelin, osteopontin, and fibulin-3. Higher amounts of these biomarkers may be an indication of mesothelioma.
Again, during the diagnostic process, blood tests likely won’t provide much value in staging. They also provide only limited information for staging once a mesothelioma diagnosis has been confirmed. They can help pinpoint mesothelioma progression or how the disease is responding to treatments, however.
The most important method for determining the stage of mesothelioma is a biopsy. Diagnostic biopsies are also the most salient way to identify if the patient has mesothelioma at all.
Biopsy methods include:
- Needle aspiration
- Endoscopy (minimally-invasive camera-assisted surgery)
- Open surgery
With endoscopies and open surgeries, doctors can visually see the scope of the disease without having to estimate based on imaging tests. The tissue samples that are removed from the body during these surgeries can also help identify the cell structure and the behavior of the disease.
Both of those are key elements in determining the stage.
Types of Staging Methods
As we’ve already noted, pleural mesothelioma has the only clinically-approved standard for a staging system. That staging system is known as the TNM method. The AJCC developed the staging method for use specifically with pleural mesothelioma. Of course, there is some overlap between all different forms of the disease. Other staging systems include the Butchart method and the Brigham method.
The acronym of the TNM system stands for tumor, node, and metastasis. These three categories make up the entire basis of the system.
Doctors will usually ask three major questions when using this staging system:
- What are the characteristics and location of the primary tumor?
- Has the disease spread to the lymph nodes?
- To what degree has the disease spread (or metastasized) to other locations in the body?
The TNM staging method is the most commonly used system for pleural mesothelioma, and its tenets can also be applied to other forms of the disease. The Butchart staging system is the oldest method and was designed prior to the advent of imaging techniques. It focuses largely on the primary tumor and its location in the body. The Brigham staging system is similar to the TNM staging system except that it also assesses the probability of surgical success.
Broadly, all staging systems can provide the patient and medical professionals with a good idea of what treatment options are available and what the prognosis will be. Mesothelioma stages are an important factor for any diagnosis.
Stage 1 Mesothelioma
Stage 1 mesothelioma has the best prognosis. It is often characterized by a tumor that is localized to one spot with limited or no metastasis. The lymph nodes also remain unaffected in stage 1.
While the prognosis is good, very few cases of mesothelioma are caught this early on. This is partial because symptoms do not start making themselves apparent until the disease has progressed much further.
Symptoms of stage 1 mesothelioma include:
- Aches in the body (in the chest for pleural mesothelioma and in the abdomen for peritoneal mesothelioma)
- Minor coughing
- Some shortness of breath (dyspnea)
In many cases, patients with stage 1 mesothelioma will exhibit no symptoms whatsoever. When minor symptoms begin to appear, most patients and doctors will likely downplay their significance. Indeed, even symptoms of later-stage mesothelioma can appear as minor medical conditions that aren’t quite as urgent.
Despite this, detecting mesothelioma in stage 1 is paramount to ensuring a good prognosis. Curative treatments are much more effective when the disease is caught in this stage. Patients can usually undergo a combination of surgery, radiation therapy, and chemotherapy to effectively slow the progress of the disease. Remission is not out of the question.
Still, because of the fast-acting nature of mesothelioma, the typical life expectancy for stage 1 mesothelioma is at a range between 21 months and 3 years. Many patients, however, can survive for numerous years beyond that. It is important to begin aggressive treatment as soon as an accurate diagnosis is made in order to improve long-term prognoses.
Stage 2 Mesothelioma
As you might expect, stage 2 mesothelioma has the second-best prognosis. At this stage, the pleural form of the disease has spread to either the lung near the primary tumor or the diaphragm. Some mesothelioma cells may have migrated to nearby lymph nodes, as well. The peritoneal form of the disease is similar except that doctors will look for minor spreading to nearby organs in the abdomen.
Symptoms with stage 2 mesothelioma are similar to those of stage 1. Again, some patients may feel no symptoms at all during this stage, making it hard to detect.
Some symptoms include:
- Persistent coughing
- Unexplained loss in weight
- Pain in the affected area
It is generally agreed that aggressive treatment methods can be curative in this stage of the disease. Again, a combination of surgery, radiation therapy, and chemotherapy can improve life expectancy greatly.
One treatment for peritoneal mesothelioma called hyperthermic (heated) intraperitoneal chemotherapy (HIPEC) has shown great efficacy in improving survival rates for individuals with stage 2 mesothelioma. In fact, patients who underwent HIPEC therapy have demonstrated a 5-year survival rate of 50%, meaning that half of those patients survived for 5 or more years after the treatment.
Still, the median life expectancy for patients with this stage of mesothelioma is only around 19 months to 2 years.
Stage 3 Mesothelioma
At stage 3, mesothelioma becomes a direr disease. The disease at this stage is still in one region of the body, but it has generally invaded several different nearby tissues, organs, and lymph nodes.
In pleural mesothelioma, tumors begin appearing on the chest wall and may end up in the lung itself or the pericardium (lining of the heart). Individual cancer cells may also be found in the chest muscles, ribs, heart, spine, or any other nearby organ or tissue.
For peritoneal mesothelioma, the spread usually cares in the abdominal cavity, though it can make its way to the chest wall. Still, it’s usually localized to one side of the body. Other organs commonly affected by stage 3 peritoneal mesothelioma include the pancreas, kidneys, and appendix.
Unfortunately, the disease is more commonly detected at this stage because symptoms start to become more prevalent and unavoidable.
Some symptoms include:
- More persistent coughing
- Heavy, labored breathing
- Tightness in chest or abdomen
- Fluid buildup in chest or abdomen
- Increased pain
Despite the localized spread of the disease in stage 3 mesothelioma, there are some cases in which surgical resection may still be an option. It really depends on the extent of the metastasis to nearby tissues and organs. Unfortunately, it is rare for this to be an option, and the median life expectancy is only around 15 months or so.
In lieu of curative treatments, patients may be given palliative therapies that aim to reduce pain and improve quality of life.
Stage 4 Mesothelioma
This is the most advanced stage of mesothelioma and the one with the worst prognosis. During this stage, metastasis has occurred on both sides of the body, and distant lymph nodes have also been affected. Organs and tissues throughout the chest wall and the abdominal cavity may be affected.
Again, mesothelioma is frequently diagnosed during this stage because of the onset of much more severe symptoms.
These symptoms include:
- Increased coughing
- More difficulty breathing
- Severe chest or abdominal pain and tightness
- Increased fluid buildup in abdomen or chest
- Weight loss
- Problems with swallowing (dysphagia)
- Coughing up blood
The chances of long-term survival after being diagnosed with stage 4 mesothelioma are slim. The median life expectancy is around one year or less for these patients. It is most common for doctors to apply only palliative treatments during this time.
Major surgeries may improve prognoses to some degree, but many patients opt against them to avoid the pain and discomfort of recovering from surgery. Smaller, less invasive procedures like the pleurodesis or paracentesis can drain fluid buildup to relieve pain and pressure.
Still, long-term survival with stage 4 mesothelioma is not impossible. With an aggressive treatment regimen and the possible application of new and emerging treatments, patients can outlive their original prognosis.
Mesothelioma staging can often dictate what treatment options are provided to patients. Virtually all treatments can either be curative (aimed at ridding the patient of the disease) or palliative (aimed at improving comfort and quality of life).
As noted above, doctors most commonly prescribe a mix of three different treatment therapies:
- Radiation therapy
Obviously, these treatments work better in the early stages of the disease because the spread is very limited. In later stages, the treatments may be purely palliative.
Surgery is often performed in early-stage mesothelioma as a curative treatment to stop the spread of the disease. Surgeries most often require the removal of organs and tissues that may be affected.
Common surgeries include:
- Pneumonectomy (lung removal)
- Extrapleural pneumonectomy (lung removal that includes removal of the affected chest and heart lining and the possible removal of portions of lymph nodes or the diaphragm)
- Pleurectomy / Decortication (removal of the lung lining and associated nearby tumors, but not the removal of an entire lung)
- Peritonectomy (removal of the affected area of the abdominal lining that is often combined with cytoreductive surgery)
- Pericardiectomy (removal of the lining of the heart)
Before and after surgery, chemotherapy and radiation therapy are applied. In some cases (like with the aforementioned HIPEC), chemotherapy treatments are administered during the surgery to provide a better result. This multimodal approach to mesothelioma treatment is currently the best method for improving outcomes.
Other treatment options like immunotherapy and gene therapy are always being studied, and many patients join clinical trials to undergo the most experimental but possibly effective treatments.
It should also be noted that, even if mesothelioma improves or gets worse over time, the stage of the disease remains the same as it was at diagnosis. For instance, someone diagnosed with stage 3 mesothelioma whose condition starts to improve will be said to have stage 3 mesothelioma in remission. Mesothelioma stages are only determined at diagnosis.