Tiny gas bubbles could hold the key to reducing the risks associated with ultrasound guided needle biopsies, routinely used to diagnose many types of cancer, including breast cancer and prostate cancer. At the moment, in a small number of cases, the procedures can sometimes dislodge cancer cells, which may then spread to other locations around the body. This can cause secondary tumours to occur which are much harder to treat and may even make a treatable cancer incurable.
To get around the problem of seeding cancer cells by mistake, NHS doctors have developed a special type of needle that is covered with an effervescent coating that produces tiny bubbles. As well as making the needle easier to see on the scan, because the bubbles scatter ultrasound waves in many directions, the bubbles also make a very smooth coating. Cancer cells find it almost impossible to stick to the bubbly surface and don’t move from their original location.
A faint trace of bubbles also remains visible in the tissue for a very brief time on removal of the needle, which helps the surgeon to reposition the needle if a second biopsy sample is required from a different place. The new type of non-stick coating may also be used on surgical devices apart than needles, including gastric tubes, catheters, and postoperative drains.
A biopsy is the removal of some tissue from a body, for examination in order to diagnose a condition. Biopsies can be done surgically or with hollow needles, using ultrasound scanning to guide surgeons who are taking the sample.
The numbers of needle biopsies performed each year are growing as the technique is easy and quick to perform. It is also easily accessible due to the requirement of basic ultrasound equipment. Needle biopsies are nearly painless and bloodless out-patient procedures. They are also much less expensive and time-consuming than surgical biopsies.
Cancer cells are more likely to dislodge than normal cells because they are bonded more loosely together and tend to emigrate. Some types of cancer cells are more mobile than others. Needle biopsies are not routinely recommended for people suffering from liver cancer for example. This is because there is a small but definite risk that a liver biopsy could spread the cancer along the pathway of the biopsy needle.
A study carried out at the John Wayne Cancer Institute of Santa Monica in California found that women suffering from breast cancer who had a needle biopsy were 50 per cent more likely to have cancer spread into the sentinel node (armpit lymph node) versus the women who had their tumours surgically removed.