Mesothelioma Biopsy

During a biopsy, a surgeon extracts a sample of suspicious tissue or fluid for analysis. A pathologist then views the sample under a microscope, analyzing the features, activity and interactions of the cells to confirm a cancer diagnosis.

Although techniques for identifying asbestos-related cancer through imaging scans and blood tests are improving, biopsy procedures are still the most important step in a mesothelioma diagnosis. Doctors can easily mistake mesothelioma for common benign illnesses — because of its vague early symptoms — or other types of cancer with similar cell characteristics.

Adding to the complexity of diagnosis, mesothelioma has three primary cell types associated with different prognoses, and its progression is divided into four cancer stages based on how far the cancer has spread.

Only a thorough biopsy analysis performed by experienced mesothelioma surgeons and pathologists can ensure an accurate diagnosis.

Various methods of biopsy exist, and depending on the invasiveness of the method used, local or general anesthesia may be required. The type and location of a patient’s tumor dictates which procedure should be performed.

Patients at risk of peritoneal mesothelioma commonly undergo a fine-needle aspiration (FNA) biopsy, while video-assisted thoracoscopic surgery (VATS) is more effective for patients at risk of pleural mesothelioma.

Video-Assisted Thoracoscopic Surgery (VATS)

The VATS technique is a type of endoscopic biopsy procedure, meaning surgeons use a thin, tube-shaped instrument with a light and a camera to look inside the patient’s body without the need to make a major incision. This type of instrument is called an endoscope, and it may also have a built-in tool for extracting tissue samples, or surgeons may use it in conjunction with other thin surgical tools.

Although this procedure requires general anesthesia, it is still considered a less invasive type of surgery, given its short recovery time and low risk of complications.

Endoscopic procedures have different names depending on where they are performed in the body:

• Thoracoscopy examines the chest cavity.
• Laparoscopy examines the abdominal cavity.
• Mediastinoscopy examines the area between the lungs.

Thoracoscopic biopsy has a remarkable track record of accurate pleural mesothelioma diagnoses because it allows doctors to see into the pleural space to evaluate cancer spread and retrieve multiple tissue samples.

In a 2008 study of 45 malignant mesothelioma patients, researchers compared the accuracy of several biopsy techniques. Thoracoscopy was associated with the highest diagnostic accuracy, confirming a diagnosis in 95 percent of patients with the disease.

Doctors may also combine thoracoscopy with a pleurodesis procedure, which is a specific intervention that involves the injection of a mildly irritating medication into the pleural space. The pleural space is the area between the lung and the chest wall.

This procedure is an attempt to “stick” the lung to the chest wall to prevent collection of fluid or air in this space. The goal is to prevent the malignant fluid from re-accumulating around the lungs. Historically, a pleurodesis procedure is generally effective about half the time in preventing a recurrence of a malignant effusion from malignant mesothelioma.

Other Biopsy Procedures for Mesothelioma

Although mesothelioma specialists rely on thoracoscopy in most cases, the procedure may not always be possible because of the tumor’s location or other complications.

Other biopsy procedures used to diagnose mesothelioma involve draining fluid buildup, extracting cells through a needle or performing tumor-removing surgery.

Draining Fluid Buildup

Thoracentesis uses a hollow needle to extract fluid from the pleural lining around the lungs. While doctors commonly perform it to remove excess fluid that causes pain and weakens lung function, the fluid obtained can also help with diagnostic analysis.

This procedure also removes cancerous fluid from the space surrounding the lungs. Through this intervention, a surgeon can often relieve painful symptoms, decrease the troublesome problems of shortness of breath and collect fluid samples for analysis. Sometimes, doctors perform a pleurodesis at the same time as the thoracentesis.

Paracentesis is a similar procedure that extracts fluid from the lining of the abdomen, while pericardiocentesis extracts fluid from the sac around the heart.

Needle Biopsies

Fine-needle aspiration (FNA) is a quick and safe biopsy procedure that uses a long, hollow needle attached to a syringe to remove up to 10,000 sample cells for analysis. This procedure is preferred for its ability to access hard-to-reach areas — such as the lymph nodes between the lungs — without the need to put the patient under general anesthesia and keep them in the hospital overnight.

Core needle biopsies use a wider needle to collect sample cells, which is a common procedure when the tumor is easily accessible. Needle biopsies are often guided by ultrasound imaging, and they usually only require local anesthesia.

Even with larger samples, however, needle biopsies are not as effective for diagnosing mesothelioma as thoracoscopic surgery, with an overall diagnostic sensitivity around 80 percent.

Tumor-Removing Surgery

In a surgical resection procedure, surgeons attempt to remove as much of the malignant mesothelioma cancer as possible. This procedure provides the most tissue for analysis, and it can eliminate the need for a second surgery if testing shows the tumor is malignant.

Thoracotomy involves opening up the chest, while laparotomy involves opening up the abdomen.