Performing a surgery on a tumor helps identify if it's cancerous or not. The biopsy requires a small amount of tissue, or the entire tumor if possible, to be removed from the body. That sample is then tested for results.
In order to get the tissue sample, the surgeon needs to know where to pull the tissue from. Usually, a computerized axial tomography image, produced with a CAT scan (or CT scan), shows where that tissue is located. The surgeon then uses tools to manually remove tissue.
The problem with a surgery begins if the surgeon does not take enough tissue or takes out the wrong tissues. When a tumor is buried deep in the body, the surgeon may be going in, more or less, blind, which can make it more difficult to get the correct tissue sample.
There are methods used to take biopsies, like using a suction tool, needle or open incision to palpate and remove the tissue directly. The most important thing to remember is that the part of the tumor that is removed must be large enough to be tested accurately. The tissues removed must be those in question.
If tissues, for example, are taken from the right breast when the left has the tumor, then it's possible that the test result would be wrong. If the tissue taken from a tumor is too close to the surface of the tumor, it may not be representative of what the tumor contains. In fact, the body sometimes surrounds cancerous cells with healthy cells, making a thorough biopsy even more important.
If you have a biopsy that comes back negative incorrectly because of a poorly performed operation, you may be entitled to compensation. Your attorney can help you look into the possibility of a medical malpractice claim.
Source: NCBI, "Surgical Components of Cancer Management," Raphael E. Pollock, MD, PhD and Donald L. Morton, MD., accessed Jan. 13, 2017