Cancer is one of the leading causes of mortality globally. Many types of cancers still remain challenging to treat, for modern medicine. Nonetheless, the prognosis is always better if the disease is diagnosed early. Diagnosis of cancer is difficult as in many cases either there are no symptoms in the early stages or symptoms are too vague.
Mesothelioma is one of the preventable, but aggressive and difficult to treat cancers. Most people diagnosed with mesothelioma do not survive more than one year after the diagnosis, which only underlines the value of early recognition of cancer.
Mesothelioma is the cancer of thin cellular line that covers most of the internal organs. The primary reason for mesothelioma is professional exposure to the asbestos. Though asbestos is banned in most industries, however, it continues to be used in specific sectors due to some of its excellent physical qualities. Mesothelioma of the lining of lungs is most common, though it may occur in any organ that is covered by serous tissue. Thus mesothelioma may occur in lining around the heart, and around the organs of abdominal cavity too.
Mesothelioma is common in elderlies, especially those who sometimes in their life worked in the mining sector, though not necessarily in the mining of asbestos. Asbestos commonly co-occurs with talk and many other minerals too. Construction workers are still at the risk of asbestos exposure as many of the old building contains it in high quantities due to its excellent insulating properties. Defense is another sector where it is still used widely in certain parts of equipment. Thus naval veterans are at higher risk of mesothelioma than other military personnel.
In more than 80% of cases of mesothelioma, there is a history of exposure to asbestosis. Thus if any person who was exposed to asbestos any time in life and develops vague symptoms characteristic of cancer like losing body weight, sweating in the evening, coughing, difficulty in breathing, he or she should immediately go for specific tests for the diagnosis of cancer.
Diagnosis of mesothelioma
Though history taking is helpful, but diagnosing cancer solely based on the patient’s complaints is rarely possible. Tests used to diagnose mesothelioma can be divided into three categories: imaging, blood tests, and biopsy.
Doctors would mostly start with imaging by using ultrasound, x-rays, MRI, CT scans, since these methods can provide a lot of information regarding cancer, they may help in differential diagnosis/exclude other conditions. Best of all, imaging methods are safe and non-invasive.
Blood tests can be divided into two groups, that is non-specific and specific blood tests. Non-specific blood tests may provide information about inflammation, general wellbeing, and help to exclude other conditions like infectious diseases or autoimmune disorders. While specific tests help to confirm the diagnosis of mesothelioma, and in some cases, they may even provide additional information regarding the type of mesothelioma.
Biopsy remains the golden standard in the diagnosis of any type of cancer. It included aspiration of a small amount of tissues from the place where cancer is thought to be located. This aspirate of tissues is then examined below the microscope to confirm the diagnosis. This method not only provides the definite information about cancer, but it also helps to differentiate between the various cancer types.
Imaging tests for mesothelioma
These are the tests used to look through the body. They help to identify the location of tumor or cancer. Imaging methods can be used more often and may also tell about how fast and aggressively the cancer is growing, and what is the effectiveness of any given treatment. These imaging tests send sound waves, x-rays, radioactive particles, or magnetic fields through the body of the person. Changes in the tissues caused due to cancer make a pattern that helps to identify cancer or other changes. Imaging methods allow printing the picture on the paper so that the condition of the patient can be analyzed thoroughly.
Most imaging tests are quite safe, meaning that they can be even used for screening in the high-risk groups, or in people with mild symptoms (where physician doubts cancer or other formations). Most of the imaging methods may show the changes in the internal organs, the formation of lump (though this lump may not necessarily indicate cancer). Imaging tests can be repeated to see if the tumor is growing or not, they also help to assist in biopsy and some other medical procedures.
- Ultrasound– it has less value in mesothelioma as it is most useful in identifying the lumps in the abdominal However, mesothelioma most commonly occurs in the lungs. Nonetheless, in case of abdominal symptoms ultrasound is highly valuable. Moreover, ultrasound is 100% safe diagnostic methods as it uses sound waves to create images of internal organs. Thus ultrasound can be repeated as many times as required. It is the method of choice in case of abdominal symptoms.
- X-ray– one of the oldest imaging techniques that are still widely used, it can show the buildup of fluids, size of tumors and their location. Though x-ray imaging can be used for any part of the body, they are highly useful in the diagnosis of diseases of the chest. An x-ray would not only give information about cancers; they would help in differential diagnosis by providing information about the other conditions that may mimic malignancies. However, x-rays have low resolution, though they are suitable for screening, but they may miss the mesothelioma in its early stages.
- Computer tomography– is technology based on x-ray but with the ability to provide far more details and create a 3D image of any part of the body. CT scan may detect much smaller tumors in comparison to the traditional x-rays.
- Positron Emission Tomography (PET) Scan– is highly efficient in staging the cancers including mesothelioma. Usually, the radiologist would inject a special drug before the scan and then carry out imaging.
- Magnetic Resonance Imaging (MRI) Scan– They are now widely available, they are safe as they use magnetic field instead of radio waves and they provide a very detailed 3D picture of internal organs. MRI scans can be used for diagnosis, screening, determining the spread of cancer, staging cancer. MRI is also helpful in making a decision regarding the treatments.
Blood tests for mesothelioma
At present no blood test can detect mesothelioma in all the cases. Nonetheless, there has been lots of progress in the direction. Nowadays, few blood tests are available that may help to detect mesothelioma in the majority of the cases. Blood tests are often preferred by the patients and doctors as they are easier to carry out, they are safe, and they provide enormous information regarding the health. Once the venous blood has been taken, the laboratory can easily carry out tens of tests.
- Complete blood count (CBC)– though it would not tell whether a person has cancer or not, but still CBC is done in all the cases. CBC provides the information regarding general wellbeing. It may help differentiate cancer from infection or other diseases. Specific changes in the CBC may be a more specific indicator of cancer.
- Mesomark– as the name suggests, it is one of the few FDA approved blood tests that are specific for mesothelioma. Though it may not detect mesothelioma in all the cases, if the test comes positive then there are really high chances of finding the mesothelioma. This test looks for soluble mesothelin-related peptides (SMRPs). SMRPs are elevated only if a person has mesothelioma. This test may be useful in the early diagnosis of cancer.
- Cancer Antigen 125 (CA125)– although CA125 are present in healthy individuals too, their levels are much lower in comparison to those who have developed mesothelioma.
- Fibulin-3– at present to tests, that is, Mesomark and CA125 are available for mesothelioma testing. However, they are not sensitive enough to detect mesothelioma in its very early stages. The reason is that both SMRPs and CA125 are present even in healthy individuals. The fibulin-3 test may change the scenario and make the early diagnosis of mesothelioma through blood tests possible. However, it is still not an FDA approved test as it is going through clinical trials.
Though discussed last, it is the most critical method in the diagnosis of mesothelioma, or in just any kind of cancer. History taking, blood tests, imaging and other techniques or analysis may tell us about the possibility of cancer. A biopsy is the only test that is 100% confirmatory, as it involves checking the cancer cells under the microscope by the highly trained pathologist. However, getting the cancer tissues is not straightforward task and biopsy is an invasive procedure, and it is the reason that why a doctor would only ask for biopsy when he or she strongly suspects cancer.
A biopsy involves small operating procedure, though with the advent of modern technologies this procedure is becoming minimally invasive. Thus in many cases, the doctor may try to get a small amount of tissue from the suspected tumor with the help of a fine needle. To ensure that needle reaches the tumor, it is often guided by one of the imaging methods like ultrasound, MRI, CT scan, or X-ray.
In a small number of cases getting the suspected tissue via sharp needle may not be possible and thus doctors may go for the minor surgical procedure. Therefore they may do an excisional biopsy, laparoscopically biopsy, or endoscopic biopsy.
Choice of method would depend on many factors, but whatever be the method final aim is to get enough tissues for microscopic examination. Examination of the extracted tissue could be done by the surgeon, radiologist, though pathologists are best trained to do this kind of job.
Some of the term commonly associated with the biopsy for mesothelioma are:
- Thoracotomy- involves getting access to the chest cavity. It is the most common type of biopsy used in mesothelioma as mesothelioma of pleura (outer lung layer) is the most common. It would not only help to get the tissue but would provide additional information regarding the spread of cancer.
- Laparotomy- would be used when mesothelioma is suspected in the abdominal cavity.
- Other methods that are less invasive are thoracoscopy, laparoscopy, mediastinoscopy.
Diagnosing the mesothelioma type
One of the main aims of biopsy is to find about the type of mutation or kind of mesothelioma, as prognosis and the treatment method directly depends on it. Most common type of mesothelioma is so-called epithelioid mesothelioma (75% cases) and has the best prognosis. While 10% may be diagnosed with sarcomatoid mesothelioma, which is the most aggressive form with the worst prognosis. Rest of the cases belong to biphasic mesothelioma or mixed type; it has characteristics of both the epithelioid and sarcomatoid type of mesothelioma.
Once the location of mesothelioma has been pinpointed, and type of cancer confirmed, doctors would try to stage cancer, that is they would estimate the spread of cancer. Depending on the location, type, and stage, decision regarding the treatment would be made.
Mesothelioma is treated with three methods that are commonly used to treat any type of cancer. That is surgical removal of the tumor, the radiological killing of the surrounding tissues, and then giving the chemotherapeutic drugs to suppress the remaining cancer cells. In advanced cancer, doctors may not go for surgery, but may still use radiotherapy and drug therapy.
Whatever be the mode of treatment, the prognosis of mesothelioma remains poor. However, it does not mean that there are not long-term survivors with mesothelioma. A small number of cases are known to have survived more than five years after the diagnosis, and there are cases that have lived more than ten years after the diagnosis. Thus hope is always there, and one should also consider the alternative treatments.
Finally, it is worth knowing that there are many funds to compensate the patients and families who have developed mesothelioma due to asbestos exposure. Looking at this legal option is important too, as it would not only compensate treatment costs but would also compensate the family for the loss of a member.