Women undergoing breast imaging with mammography, ultrasound, or MRI, may receive a recommendation at some point during their lifetime that a biopsy is recommended. A core needle biopsy is the standard of care when it comes to diagnosing a suspicious abnormality seen on breast imaging. However, a long-held belief by a number of patients has been that a biopsy can cause cancer cells to spread. This fear stems from the idea that tumor cells can get displaced in the surrounding breast tissue through the needle tract at the time of biopsy. While there are rare case reports of this happening, in a vast majority of cases, this has no clinical impact. Needle biopsies have been demonstrated to be safe and accurate and are also less deforming, less invasive, and less expensive than open surgical biopsies. In fact, studies have shown that patients who undergo a needle biopsy for cancer do not have an increased risk of local recurrence or death, and may even have a better outcome and longer survival than patients who do not have a pre-operative needle biopsy. (1-4)
So, what exactly is a needle biopsy and how is it done? A biopsy is a sampling of tissue that is obtained in order to establish a diagnosis. A small amount of local anesthetic is used to numb the area prior to the needle being inserted. The simplest and least traumatic needle biopsy is a fine needle aspiration (FNA), in which a thin needle, is inserted into the tumor and aspirated. Since FNA uses such a small needle, there is a risk that the biopsy could miss the cancerous cells, producing a false negative result. Another drawback of FNA is that it cannot differentiate between non-invasive cancer and invasive cancer. For this reason, larger gauge needles are frequently used for breast biopsies, often with the aid of a spring loading device, known as a biopsy gun. Additionally, some biopsies are performed with vacuum assistance which allows larger specimens to be obtained. If a needle biopsy is inconclusive or shows atypical cells, the next step is often an open surgical biopsy performed in the operating room to excise a larger area of tissue to make a diagnosis.
When it comes to the treatment of breast cancer, the gold standard is to perform a needle biopsy prior to undergoing a surgical procedure to remove the tumor. The goal of the needle biopsy is to remove a small representative sample of the tissue in order to establish a diagnosis and guide treatment. A tiny titanium clip or marker is left in the breast tissue at the site of the biopsy for future reference showing that the area has been sampled. Additional information can be gained from a biopsy of a breast cancer by staining the tumor cells for specific receptors called the estrogen, progesterone and HER2 receptor. This information can be extremely helpful in tailoring treatment options for patients to offer them the best outcome.
In summary, physicians and patients should feel reassured that a biopsy is very safe. Anxious patients, who may inquire about the risk of a biopsy causing tumor cells to spread, can feel relieved that microscopic displacement of cells appears to have a negligible clinical effect. While undergoing a biopsy will not cause cancerous cells to spread, delaying or avoiding a biopsy over this fear may lead to a worse prognosis. It is important to note that only 20-35% of patients undergoing a breast biopsy for suspicious imaging findings will actually end up having a cancer. A majority of patients will have benign results that will require no further treatment. If you are recommended to undergo a breast biopsy and have questions or concerns, be sure to discuss these concerns with your primary care provider or a breast specialist prior to undergoing the biopsy.
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References:
1: Ngamruengphong S, Swanson KM, Shah ND, Wallace MB. Preoperative endoscopic ultrasound-guided fine needle aspiration does not impair survival of patients with resected pancreatic cancer. Gut. 2015 Jul;64(7):1105-10.
2. Fitzal F, Sporn EP, Draxler W, Mittlböck M, Taucher S, Rudas M, Riedl O,Helbich TH, Jakesz R, Gnant M. Preoperative core needle biopsy does not increase local recurrence rate in breast cancer patients. Breast Cancer Res Treat. 2006 May;97(1):9-15.
3. Taxin A, Tartter PI, Zappetti D. Breast cancer diagnosis by fine needle aspiration and excisional biopsy. Recurrence and survival. Acta Cytol. 1997 Mar-Apr;41(2):302-6.
4. King TA, Hayes DH, Cederbom GJ, Champaign JL, Smetherman DH, Farr GH, Bolton JS, Fuhrman GM. Biopsy technique has no impact on local recurrence after breast-conserving therapy. Breast J. 2001 Jan-Feb;7(1):19-24.
