Biopsies are the last step in a mesothelioma diagnosis and the only way to confirm that a patient has the cancer. The most common types of biopsies used are needle biopsies, camera-assisted biopsies and surgical biopsies, each with varying degrees of invasiveness.
Mesothelioma biopsies are meant to remove a sample of affected tissue or fluid for analysis, to then confirm malignancy, mesothelioma type, cell type (epithelioid, sarcomatoid or biphasic) and staging. This step in the diagnostic process will help determine viable treatments and provide a more accurate prognosis for the patient.
Biopsies and Diagnosing Mesothelioma
A biopsy is many times the last step in a diagnosis, after imaging tests and bloodwork. Biopsies typically aren’t ordered until there are signs and symptoms that point toward a cancer diagnosis, since they are an invasive procedure.
If abnormalities are found during an image scan, patients will undergo a biopsy, where a tissue or fluid sample is collected for analysis in a process called pathology. The analysis will allow specialists to determine whether a tumor is malignant or benign, confirm mesothelioma and determine cell type (epithelioid, sarcomatoid or biphasic). A biopsy is the only way to confirm a cancer diagnosis, and is therefore crucial in determining a patient’s treatment options and prognosis.
Types of Mesothelioma Biopsies
There are three types of biopsies that are common during a mesothelioma diagnosis, including needle biopsies, camera-assisted biopsies and open surgery biopsies. The type of biopsy that is performed will be determined based on malignant mesothelioma type.
Needle Biopsies
Needle biopsies are considered closed (non-surgical) procedures that are usually quick with little to no recovery time. Like any procedure, there are risks involved, including mild pain and discomfort, bleeding or damage to nearby organs (less likely), depending on needle biopsy type and location.
Needle biopsies differ based on location. Often done to remove fluid from the affected area, these biopsy types are also used as palliative treatments to relieve pressure and reduce symptoms of pleural, peritoneal and pericardial effusion. Many times, analysis of fluid will not reveal definitive evidence for mesothelioma, which will then necessitate another type of biopsy procedure. A needle can also be inserted directly into an area of tumor, such as the pleura, which can then produce what is called a core needle biopsy sample, which is more likely to lead to a definitive diagnosis than a fluid sample.
Thoracentesis
A thoracentesis is most often performed to remove fluid from the space between the lungs and the chest wall. Most commonly, the doctor will numb the area with a local anesthetic and then insert the needle into the patient’s back along the midscapular line (about midway between the spine and flank). After the fluid is drained, the needle will be removed and the area will be covered with a sterile bandage.
Paracentesis
A paracentesis is performed to remove excess fluid from around the abdomen. Typically, the area where the needle is to be inserted will be shaved, cleaned and numbed with a local anesthetic. The doctor will then insert a fine needle into the abdominal area and drain the fluid into a syringe. If a very large amount of fluid is present, a catheter may be mounted to the syringe so that fluid can be collected in a vacuum bottle. When enough fluid is collected, the needle will be withdrawn and the area will be covered with a sterile bandage.
Pericardiocentesis
A pericardiocentesis is performed to remove excess fluid from the thin space between the heart and the pericardium. With this type of biopsy, the doctor will sterilize and numb an area of the chest immediately below the sternum where the needle will be inserted. An echocardiogram is often used to help guide needle placement during the procedure. After the biopsy, the needle is withdrawn and the area is covered with a sterile bandage. In some cases, a catheter may be inserted to allow fluid to continue draining.
Core Needle Biopsy
A core needle biopsy is a minimally invasive procedure that involves the use of a CT scan or ultrasound to guide a needle through the skin into an area of suspected tumor, such as thickened pleura. A piece of tissue is removed with the needle and then analyzed by pathologists. After the biopsy, the needle is withdrawn and the area is covered with a sterile bandage. This type of sample (termed surgical pathology) allows pathologists to diagnose mesothelioma with greater likelihood than fluid analysis (termed cytology).
Camera-Assisted Biopsies
Camera-assisted biopsies, or endoscopies, are considered “minimally invasive” procedures that allow doctors to visually inspect the tumor and obtain a tissue sample large enough for proper analysis. Recovery is typically quick, though there are some risks involved, including infection, bleeding, injury to nearby organs or organ failure in severe cases. Risks are also associated with anesthesia administration including allergic reactions, headaches and nausea.
Like needle biopsies, there are several different types of camera-assisted biopsies, depending on location. For mesothelioma, the most common types include thoracoscopy, laparoscopy and mediastinoscopy.
Thoracoscopy
After anesthesia is administered, the surgeon will make several small incisions in the chest and between the ribs to access the pleural cavity or thoracic cavity. The scope is inserted and if the tumor is seen, a small tissue sample is removed for analysis.
Laparoscopy
Laparoscopy is most commonly used when peritoneal mesothelioma is suspected. Small incisions are made in the stomach and the abdomen is inflated with gas (usually carbon dioxide) to access the peritoneal cavity and get a clear view of the abdominal organs. A small scope (laparoscope) is inserted with a light and camera to locate tumors and remove a tissue sample for analysis. Once the sample is taken, the scope will be removed and the gas is released from the abdomen.
Mediastinoscopy
A mediastinoscopy is common when pericardial mesothelioma is suspected or when metastasis to the chest is present. A mediastinoscope is used to look at the mediastinum, or the space between the sternum and middle of the chest, between the lungs. First, an endotracheal tube is inserted into the patient’s nose or mouth to assist with breathing. An incision is then made below the neck for insertion of the scope for the surgeon to locate the tumor or abnormal lymph nodes and remove a tissue sample for analysis.
Resources for Mesothelioma Patients
Surgical Biopsies
Surgical biopsies differ from needle and camera-assisted types in that they are much more invasive. Doctors are conservative when ordering surgical biopsies, only prescribing them when results of less-invasive procedures are inconclusive or when the area cannot be reached easily with a needle or endoscope.
The benefit of collecting a mesothelioma biopsy through surgery is access for obtaining a large tissue sample, though there are risks involved such as infection, bleeding, injury to organs or blood vessels, fluid buildup and pain, as well as allergic reactions, nausea, headaches and vomiting as reactions to anesthesia.
Surgical biopsies require the longest amount of recovery time, but recovery and side effects may differ based on patient age, overall health and what type of surgical biopsy was performed. The most common surgical biopsies for mesothelioma include a thoracotomy and laparotomy.
Thoracotomy
A thoracotomy is an open-chest procedure that gives doctors access to the thoracic cavity to obtain a biopsy. This is most commonly used for pleural mesothelioma, but has also been used for cases of pericardial mesothelioma. During the procedure, a thoracic surgeon will make an incision in the chest wall to then evaluate areas around the lungs, heart or other affected areas where metastasis is suspected. When abnormal tissues or tumor masses are found, samples are collected for analysis.
Laparotomy
A laparotomy is an open abdominal procedure commonly used to obtain a biopsy when peritoneal mesothelioma is suspected or peritoneal effusion (fluid buildup) is found. During the procedure, a surgeon will closely examine the abdominal organs to identify tumors, abnormal tissues or causes of effusion. If found, a biopsy is performed to remove a sample for analysis to confirm diagnosis.
In some cases, surgeons may decide to conduct an emergency surgery to remove any tumors they find during a surgical biopsy procedure. In such instances, the doctor generally will use the same incision.
Diagnosis After a Biopsy
The only way to definitively diagnose mesothelioma is with a biopsy. When a biopsy is collected, it’s sent for pathological analysis. These findings will confirm malignancy, cancer type, cell type and staging, while also helping specialists to provide patients with treatment options and a prognosis.
