Last modified: December 16, 2020
Fine needle biopsies are less invasive than other diagnostic procedures, such as surgical biopsies or core biopsies. A fine needle aspiration takes only a few minutes and provides a sample of cells for laboratory workers (called cytopathologists) to study under a microscope.
Oncologists may order a fine needle biopsy if an imaging scan shows a mass on the breast, thyroid or certain lymph nodes. Fine needle biopsies are not generally used when mesothelioma is suspected because more reliable, but more invasive biopsy methods are are needed, such as a thoracoscopy, to understand the type of mesothelioma and decide what treatment is appropriate.
Mesothelioma may be discovered when an oncologist orders a fine needle aspiration of lymph nodes in the armpit or neck from the biopsy.
Imaging Techniques Help Guide the Needle
Fine needle biopsies are relatively simple. A doctor inserts a long, thin, hollow needle directly into the suspicious mass, then draws a small section of tissue through the needle.
In some cases — such as when the tumor is not directly under the skin — doctors use imaging techniques to guide the needle. These imaging techniques are especially helpful when doctors attempt to diagnose thoracic cancers with a fine needle aspiration.
The process is not painful, although some patients feel a slight prick when the needle is inserted into the skin. Many patients opt for numbing cream to prevent discomfort. Complications are extremely rare, but can include infection or bleeding at the insertion site. Fine needle aspirations are less likely than other biopsies to cause severe complications such as a collapsed lung.
Most doctors can perform this procedure in their office. Patients can go home directly following the biopsy, and most patients receive their results within two or three days.
Using Fine Needle Aspirations to Diagnose Mesothelioma
Fine needle aspiration is not the go-to biopsy technique used to diagnose mesothelioma. The most accurate biopsy for mesothelioma is a thoracoscopy. A fine needle biopsy may accidentally discover mesothelioma, but this instance is rare.
The diagnostic accuracy of fine needle aspirations for mesothelioma depends on several factors, including the size of the tissue sample and the type of mesothelioma cells present.
Fine needle biopsies can rarely be definitive enough to diagnose malignant mesothelioma. Additional tests, such as a thoracoscopy, is often necessary to determine the cell type and confirm the diagnosis.
In some cases, cytopathologists extract molecules called RNA (ribonucleic acid) from fine needle biopsy samples. They then perform molecular tests on the RNA to further confirm an accurate mesothelioma diagnosis.
Procedure Is Common When Testing for Cancer
The advantages of a fine needle biopsy include simplicity and low cost. Because they are easy to perform, they may contribute to an earlier diagnosis, which is crucial in the treatment of mesothelioma and most other cancers.
A fine needle aspiration is used to detect breast cancer, allowing a doctor to remove cells from a suspicious lump in the breast. It is a quick way for a doctor to sample a lump that was felt during a clinical breast exam. The procedure is easier than the common core needle biopsy and reduces the chance of any infection or bruising.
There are times when results from a fine needle biopsy are not conclusive with many cancers, even when a skilled specialist is involved.
The results typically are grouped into four categories:
- Clearly Benign: No sign of cancer
- Clearly Malignant: Definitively cancer
- Less Clear: Nondefinitive indication of cancer
- Inadequate or Insufficient: Sample not adequate to confirm a diagnosis
If the result clearly confirms the presence of cancer and provide the necessary information, a patient may not have to undergo more invasive diagnostic procedures.
This may not be the case with mesothelioma because a fine needle aspiration does not provide the necessary information for accurate diagnosis, or information necessary to decide the appropriate treatment.
A nondefinitive result will be followed by further procedures for additional biopsy.
Downside of Fine Needle Aspirations
With certain cancers, doctors may be unable to make a definitive diagnosis from cell samples obtained in fine needle aspirations.
While it is considered an important diagnostic tool, a fine needle aspiration may limit the preoperative evaluation of cancer patients.
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