Does a biopsy carry cancer cells?
As this question is frequently asked, this risk should be given special attention. Patients often express the fear that cancer cells could be distributed in the breast by taking a tissue sample. This fear is essentially unfounded.
Research has shown that the growth of individual cancer cells in the punctured tissue is extremely unlikely. There are, however, differences between different types of cancer and between the different removal techniques. For the two types of cancer for which biopsies are most frequently performed in diagnostics, breast cancer and prostate cancer, there is no evidence to date that displaced tumour cells have led to the development of new cancer foci.
However, it may well be more frequent in other forms of cancer, such as certain types of ovarian cancer. The risk can never be completely ruled out. Which form of biopsy is ultimately used can only be clarified in an individual consultation with the treating physician. The following information is therefore only general background information. There are always new variations in the described techniques of specimen collection, which differ in details, and we are constantly trying to improve the current techniques.
Fine needle puncture
In fine needle puncture, individual cells or cell clusters are taken directly from the node using a syringe and a very fine cannula (only 0.5 mm in diameter, thinner than a pin). The examination result is usually available on the same day. The quality of the fine needle puncture is highly dependent on the experience of the examiner.
In the case of malignant findings, the diagnosis is 96 % certain. In the case of benign findings, unfortunately only 90 %, i.e. in the case of a palpable lump, negative findings cannot always be relied upon. Since only individual cells are removed during fine needle puncture and not entire pieces of tissue, it can be difficult for the pathologist to make statements, e.g. about grading or the type of growth. If necessary, an additional punch biopsy can then be performed. Fine needle puncture is only used by a few specialised examiners and is increasingly being replaced by punch biopsy.
Punch biopsy
The punch biopsy is another possibility to take a tissue sample from an abnormal palpation and/or mammography finding. Here, a needle with a diameter of approx. 1.6 mm is shot into the tissue at high speed.
This technique ensures that the insertion of the needle is actually no more unpleasant than a blood sample. However, a small skin incision under local anaesthetic is additionally necessary. The needle is shot by an experienced examiner “under sight” directly into the findings in question.
Under sight means that an ultrasound of the breast is made at the same time, on which the findings, the needle and its position can be seen. Usually three different punches are taken from three different areas of the tumour, but further punches may be necessary. More tissue can be removed with the punch biopsy than with a fine needle puncture.
Inside the needle is a cavity in which a tissue dressing can be taken as a punch. The sample is then sent to the pathologist. With the punch biopsy, the diagnosis is almost as reliable as surgical removal of the tumour. In the case of a malignant finding, the certainty of the diagnosis is 98 % and even in the case of benign findings, the certainty is over 90 %. With the punch biopsy, many unnecessary surgical interventions can be avoided in the case of benign findings.
