A fine needle aspiration biopsy uses a very thin needle to extract tissue or fluid from a potentially cancerous mass for diagnosis. Most patients undergo this type of biopsy before more invasive procedures to confirm a mesothelioma diagnosis.[1]
What Is a Fine Needle Aspiration Biopsy?
Fine needle aspiration is a common type of biopsy procedure. During this type of biopsy, doctors use a thin needle to draw fluid or tissue into a vacuum. Fine needle aspiration is a quick and easy outpatient procedure.[2]
Fine needle aspiration is also considered low-risk. For this reason, it is often the first step in a mesothelioma diagnosis. Doctors can use it to take fluid and cell samples from the pleura, abdominal cavity, or pericardium for diagnostic purposes.[2]
What Can Fine Needle Aspiration Biopsy Diagnose?
Biopsies of all types are used to diagnose cancer or to rule out cancer in an area of abnormal tissue. Doctors can use fine needle aspiration biopsy to diagnose most types of cancer, but it is more commonly used to take samples from the thyroid, lungs, skin, liver, breasts, and lymph nodes.
Doctors can also use fine needle aspiration to diagnose cancer deeper in the body. An endoscope is a flexible tube with a light and camera that allows the doctor to see and reach inner areas of tissue for sampling.
A fine needle aspiration biopsy done with an endoscope is more invasive. It requires a small surgical incision but is still a simple outpatient procedure.
How Accurate Is a Fine Needle Aspiration Biopsy? Blind Versus Guided
A blind fine needle aspiration is a biopsy performed without imaging to guide it. This yields a very low success rate and can lead to false negatives.
A negative result does not necessarily mean there is no cancer; instead, the needle did not properly take a sample from the correct place, and more procedures may be required.
Doctors may use a fine needle biopsy after a patient has had a chest x-ray to confirm a pleural effusion (fluid build-up in the pleura). The needle doesn’t need to be guided to extract fluid for examination. This procedure is not perfectly accurate in diagnosing mesothelioma.
A guided fine needle aspiration is a biopsy used in conjunction with an imaging technique. It provides more accurate and safer results. Ultrasound or CT scans are the imaging methods used most often. The imaging helps guide accurate needle insertion. This technique is much more effective for accurate mesothelioma diagnosis.[3]
Fine Needle Aspiration of the Lymph Nodes to Diagnose Mesothelioma
Diagnosing pleural mesothelioma is not a simple process. Mesothelioma is often misdiagnosed as something less serious. This misdiagnosis can shorten life expectancy.
In some cases, a fine needle biopsy of the pleura ruled out mesothelioma, but a subsequent biopsy of the lymph nodes confirmed it.
Although pleural mesothelioma is cancer of the pleura, testing tissue in the lymph nodes will give a more accurate diagnosis for some patients. This may be because the cancer has spread from the pleura to the lymph nodes, where cancer cells are easier to detect.[4]
Fine Needle Aspiration vs Core Biopsy
A core needle biopsy is similar to fine needle aspiration. The main difference is that the needle is larger and removes a core of tissue. It provides pathologists with a larger tissue sample for analysis, approximately one-half by one-sixteenth of an inch.
Neither biopsy is invasive, and both require just a local anesthetic. However, the larger core biopsy may be more uncomfortable later for the patient.
The downside to the fine aspiration biopsy is that it might not provide enough cells for a diagnosis. On the other hand, patients often get results faster than with a core needle biopsy.
How Is a Fine Needle Biopsy Done?
It’s normal to feel nervous about any medical procedure; however, a thin needle biopsy is relatively simple, quick, and only mildly uncomfortable. Still, knowing what to expect can help ease your mind and make you feel more comfortable:[5]
- First, the skin area where the needle will be inserted is cleaned and disinfected. This prevents infection due to the needle’s penetration of the skin. The doctor or assistant then covers the surrounding area with sterile materials.
- Depending on the biopsy’s location and the needle’s size, you may be injected with a local anesthetic to numb the area. The numbing itself will cause a slight sting or pinching feeling.
- During a guided biopsy, the doctor may use an ultrasound device to image the area under the skin. Imaging is painless and allows the doctor to see where the tissue to be sampled is located, making the procedure quicker and more accurate.
- Finally, the doctor will insert a thin needle attached to a syringe into the skin. The syringe has a vacuum that pulls up fluid, tissue, or both from the suspected tumor. Overall, the process is relatively quick.
After the Biopsy
A fine needle biopsy is quick and causes few side effects. Complications of this procedure are unlikely; however, you may experience pain or swelling at the needle site.
An over-the-counter medication will reduce soreness and inflammation. In rare cases, a patient may experience a hematoma (bleeding under the skin) or infection.[5]
Getting Biopsy Results
Depending on the lab, results from a fine needle aspiration biopsy may take up to seven days. Typically, there will be one of four results: definitely not cancer, definitely malignant cancer, non-definitive, or inadequate sample for results.
When results are definitely cancer or are unclear, the next step is usually a more invasive biopsy. With inconclusive results, doctors will usually perform another needle biopsy.
Fine needle aspiration biopsy for mesothelioma is useful for diagnosis, but this method is not perfect. Cancer cannot be definitively diagnosed or ruled out using this technique. This is why diagnostic strategies typically include several procedures for the greatest accuracy.
