In order to accurately diagnose mesothelioma, a biopsy of the infected area must be taken and analyzed. A sample of the infected tissue or fluids will be taken and analyzed under a microscope by a pathologist. Biopsies are currently the best way to get an accurate diagnosis. The information discovered in the analysis of the biopsy also provides doctors with critical information about the type of mesothelioma so they can determine the best route of treatment and give a prognosis.
There are several different biopsy procedures which may be used to analyze suspected mesothelioma. Which procedure is used is largely based on where the infected area is located. For example, if masses are found in the lungs (such as with pleural mesothelioma), a patient may undergo a thoracoscopic biopsy which uses a specialized instrument for looking inside the chest. Biopsies are usually only minimally invasive; they are typically performed with a local anesthesia as an outpatient procedure.
Fine-needle aspiration
This is one of the simplest methods of biopsying a suspicious mass in the body. During the procedure, a doctor uses a very thin needle to draw a sample of the infected area. The patient will first receive a local anesthetic at the area where the needle will be inserted. Patients may feel a brief stinging pain during the anesthesia process and, during the actual biopsy, a feeling of pressure from the needle. There may be some bruising or soreness to the area after the procedure.
The benefit of fine-needle aspiration biopsy is that is minimally invasive. Because the needle used for the biopsy is so small, it allows doctors to take samples from masses in areas which would be hard to reach during more-invasive procedures. While fine-needle aspiration is considered very safe, complications can occur, such as infection. It is also possible that the needle misses the suspected mass and the procedure has to be repeated.
Fine-needle aspirations are usually guided using imaging equipment like the sonograph or other sophisticated imaging technology. Extracting the right tissue is critical to a successful mesothelioma diagnosis.1
Thoracoscopy (pleuroscopy)
A thoracoscopy is used for biopsying suspected pleural mesothelioma. As pleural mesothelioma is the most common type of the cancer, this is one of the most widely-performed mesothelioma biopsy procedures.
During a thoracoscopy, a small incision is made in between the ribs so a pleura-scope (a thin tube with a video camera attached to it) can be inserted into the lungs. The pleura-scope will be used to visually examine the lungs and locate suspicious masses. An imaging scan may also be performed before the thoracoscopy to inform the surgeon about the location of masses. Once the suspicious tissues are located, a small sample of them will be taken so they can be later analyzed under a microscope by a pathologist.
Patients undergoing a thoracoscopy will first receive a local or general anesthetic. In most cases, the patients are put under unconscious sedation though it is possible for the patient to be awake during the procedure as well. Once the anesthesia is complete, an incision or incisions are made between the ribs and the exploration and biopsy are performed. After the procedure, the tube is removed and another tube is put in its place to drain fluids from the lungs and prevent air from building up in the incised cavity. The area of incision will then be closed.
In order for a thoracoscopy to be performed, patients’ lungs must be partially or fully deflated. Thus, the patients will be placed on a ventilator during the procedure and have their breathing monitored by an RN or respiratory therapist. Lung deflation can be risky, particularly if the patient has a history of lung problems. However, thoracoscopy is generally a safe procedure and complications are uncommon. It has proven to come close to 100 percent accuracy in the diagnosis of malignant pleural effusions.2
Thoracentesis
Also known as a pleural tap, a thoracentesis is similar to fine-needle aspiration biopsy as it also uses a needle. However, a thoracentesis for diagnosis uses a needle to remove fluids rather than tissues from the pleural space of the lungs. The biopsy procedure can be used for diagnosing pleural mesothelioma.
During the procedure, patients will be required to sit leaning forward with their backs exposed. The area where the needle will be inserted will be numbed with a local anesthetic. After the anesthesia is complete, the doctor will insert the needle into the site and to the pleural space of the lungs. Fluid will be removed from the space and sent for analysis. In addition to diagnosis, a thoracentesis can also be used to remove fluid from the pleura to make breathing easier for patients with pleural effusion.
Thoracentesis is minimally invasive and generally a very safe procedure. There are some risks with this procedure including partial lung collapse, pulmonary edema, infections, hemorrhaging, or (rarely) damage to other organs. It can done using ultrasonography guidance which reduces potential complications like hemorrhaging.3 A thoracentesis is typically followed by an x-ray to ensure that no complications occurred. The procedure itself is generally not painful but can be uncomfortable. While the fluids are being withdrawn, patients may feel a suction-like feeling inside their chests.
Thoracotomy
A thoracotomy is an invasive surgical biopsy procedure that is typically only used for diagnosis if other methods are deemed unsafe. During the procedure, the patient is put under general anesthesia and a significantly large incision is made into the chest which is typically 3-4 inches long. The surgeon will then examine the pleural space of the lungs and collect tissue samples for analysis.
Thoracotomies are major surgeries and generally require a minimum of five days of hospitalization. They are also riskier than many other biopsy procedures with potential complications such as hemorrhaging, infections, organ damage, or fluid buildup, amongst others.
Laparoscopy
If peritoneal mesothelioma is suspected, a doctor may recommend a laparoscopy. This biopsy procedure is minimally invasive and uses a small tube with a video camera attached to explore the abdominal area for abnormalities. Before the procedure, patients will first be put under a general anesthetic. The surgeon will make a small incision or incisions into the abdomen. The surgeon then will insert a hollow needle into an incision. Either carbon dioxide or nitrous oxide gas will be then slowly put into the abdomen through the needle. The gas is used to inflate the abdomen so the surgeon can get a clearer view of the internal organs during the laparoscopy.
After the abdominal area is inflated, the surgeon will put a laparoscope (a thin tube with a camera attached) through an incision to look within the abdominal area. Other instruments may be attached to the laparoscope, such as a laser, to help take tissue or fluid samples. When the procedure is complete, the laparoscope is removed and the gas is slowly released from the abdominal area. The incisions are closed with stitches and the patient is taken to recovery.
A laparoscopy generally takes 30-90 minutes to complete and recovery is typically just several hours. Laparoscopies are generally done as outpatient procedures and patients can return to normal activities the next day. Patients may feel some soreness at the incision sites but laparoscopy recovery is not typically painful. Laparoscopies are generally very safe but there is some risk of complications like infection, hemorrhaging, and organ damage.
Laparotomy
A laparotomy is an invasive surgical procedure which is used for investigating the abdominal area. It may be recommended if peritoneal mesothelioma is suspected. During the procedure, the patient will be put under general anesthesia and a large incision will be made in the abdomen (approximately 4 inches long). The surgeon will examine the abdominal area for abnormalities and may take tissue or fluid samples for analysis. If suspicious masses are found during the laparotomy, it is common for them to be immediately excised. Patients are generally required to stay at least one day in the hospital after the procedure. As with all surgical procedures, laparotomies do have risks of complications such as hemorrhaging, infection, and organ damage.
Madiastinoscopy
A madiastinoscopy biopsy uses a thin scope called a mediastinoscope to analyze the upper part of the chest and area in front of the lungs called the mediastinum. The process involves a surgeon making a small incision in either the neck or chest and then inserting the mediastinoscope into the body. Mediastinoscopies can be very useful for detecting lung problems including mesothelioma. It can also be used for detecting other problems, particularly to the lymph nodes.
Before the procedure, patients will be put under general anesthesia and also receive breathing support. Once anesthesia is underway, a surgeon will insert the mediastinoscope and investigate the chest and lung area. Fluid or tissue samples will be taken for analysis in a laboratory. The procedure generally takes about an hour, after which the incisions are closed with stitches. Patients quickly recover and can generally return home the same day. Madiastinoscopies are considered very safe with minimal risk of complications. However, it is common to feel some discomfort after the procedure.
As you can see there is a number of biopsy procedures used to accurately diagnose mesothelioma. The doctor will choose one or more methods that are most likely to give the best results.
References
1 Ho, L. M., Thomas, J., Fine, S. A., Paulson, E. K., (June 2003) Usefulness of Sonographic Guidance During Purcutaneous Biopsy of Mesenteric Masses, v180:6, 1563-1566.
2 Michaud, G, Berkowitz, D.M., and Ernst A.(Nov 2010) Pleuroscopy for diagnosis and therapy for pleural effusions. Chest, v138:5, 1242-6.
3 Patel. P. A., Ernst, F. R., and Gunnarsson, C. L. (12 Oct 2011) Ultrasonography guidance reduces complications and costs associated with thoracentesis procedures, J Clin Ultrasound, doi: 10.1002/jcu.20884.
