Biopsies are becoming less invasive and more accurate, according to a recent study published online by the journal Radiology.
I spoke with the study's lead author, Dr. Sharon Kwan, radiology resident at the University of California in San Francisco, about what the findings mean for patients -- and for the future of medicine.
How has the performance of biopsies evolved over the years?
This idea of taking a small piece of tissue from the body to examine under the microscope to help make a diagnosis or solidify a diagnosis is something that's been around for centuries. But we have all these new imaging tools like CT, MRI and ultrasound and that's what we wanted to explore in the study. These technologies enable us to make all these diagnoses with significantly more confidence. Despite this, there are still a lot of cases where a biopsy is needed to make a more definitive diagnosis. We wanted to look at how the performance of this procedure has changed in the context of the relatively recent widespread availability of these advanced imaging technologies.
Biopsies can be done in a variety of different ways. One way is direct visualization. If you have a lesion on your arm, that's not much of an issue. If it's something more deep, like in the liver, you'd have to do it during open or laparoscopic surgery. You can also take a biopsy when you have a tube going into the body. All of these techniques are rather invasive and come with their own risks. Another way to do it is percutaneously. You do it without cutting the skin, by directing a thin needle through the skin to the area of interest. Before CT or MRI, that could be pretty difficult to do. [With those new imaging techniques] you can see a very small lesion in the liver very well and you can precisely direct a needle into it. You can do this while avoiding hitting any vital structures. Now that we have these advanced imaging modalities, you can do a percutaneous biopsy with much more precision and much more safely.
Your study found that many more physicians were doing percutaneous and image-guided biopsies. What does that mean?
During the last decade, there has been an increase in the number of biopsies done via the percutaneous route. To some extent, this was due to substitution of this route from the old way of doing things, such as with open surgical biopsy. When we look specifically at biopsies performed percutaneously, we found that more of those were being done with imaging guidance. This supported our overall theory that the relatively recent introduction of these advanced imaging technologies has changed the way biopsies are done.
What does this tell us about the future of biopsies?
Based on the trends we found, it's likely there will be continued growth in the relative percentage of biopsies done via the percutaneous route and, more specifically, done percutaneously and with imaging guidance. [But] there's always going to be a place for the other ways of performing biopsies because medicine always comes down to the individual patient.
What does the growth in percutaneous and image-guided biopsies mean for the patient?
These changes reflect overall acceptance of this way of performing biopsies as the safer and more effective way. Should patients find themselves in a situation where they need a biopsy, it's most likely they'll get a biopsy with just a small needle going through the skin. That's great news. The other thing to note is that there's a good chance a radiologist will be the person doing this procedure. You don't need a surgeon to do this. They can just do it on a CT scanner or under the MRI magnets.
Image, top: Dr. Sharon Kwan
Image, bottom: CT-guided percutaneous lung biopsy / Courtesy of Sharon Kwan