Patient Information on Fine Needle Aspiration
What is a fine needle aspiration (FNA)?
Fine Needle Aspiration is a method of taking a small amount of tissue from a lump in the body, in order to find out what it is. A small needle (usually smaller than one that is used to draw blood) is inserted into the lump and tissue is dislodged by movement of the needle and by gentle suction. The tissue is smeared onto slides and sent to the laboratory for staining, and then examined microscopically by a pathologist. The pathologist will make a diagnosis (find out the cause of the lump) and send a report to your doctor.
Is FNA painful?
No procedure is completely painless. However, the needles used in FNA are very thin, smaller than those used to draw blood. Also, local anesthesia is often used before the FNA, so that you are more comfortable.
If you are sore after the procedure, a simple pain reliever such as Tylenol (no nonsteroidal anti-inflammatories, i.e. Advil) or an ice pack may alleviate mild symptoms.
How accurate is FNA?
Most doctors consider FNA to be a very good test. Overall, it is about 90-95% accurate when the aspiration and interpretation are done by an experienced cytopathologist. However, the test is not perfect. There is a small chance (usually less than 10%, depending on the size, location and nature of the lump) that the FNA will not be interpreted as cancer when cancer is there. Very rarely (usually less than 1% of the cases), FNA may be falsely interpreted as cancer when cancer is not there. It is very important that you return for follow up with your doctor after the FNA. He/she will use the results of the FNA and other clinical information to determine if further tests or treatment are necessary.
What are the risks of FNA?
As with any procedure in which the skin is broken (like having your blood drawn), there is always a risk of pain, bleeding, bruising or slight tenderness at the aspiration site. Very rarely, an infection may occur after an FNA. In extremely rare cases, air may be introduced into the pleural (lung) cavity causing shortness of breath (pneumothorax) after an FNA of the breast or chest wall. However, the benefits of the FNA far outweigh the risks.
What are the alternatives to FNA?
The alternative is to do a biopsy, which is done with a much larger needle or by an operation. Surgery is more difficult, has more complications, and may take a while to schedule. An FNA is simpler, cheaper and has fewer complications.