Can a needle biopsy be harmful to a GIST patient?
I read the following statement at the American Cancer Society website. "Needle biopsy is not recommended by most doctors for GISTs. Although needle biopsies are safe to use in most cancers, many doctors feel they are dangerous in GISTs because they might spread the cancer cells."
Could seeding of tumor cells along the track of the biopsy needle result in new tumors?
GIST Support International put this question to Christopher Corless, MD PhD, who is Professor of Pathology at Oregon Health & Science University.
Dr. Corless completed his medical and graduate school training at Washington University, St. Louis, and his residency in Anatomic Pathology at Brigham & Women's Hospital, Boston. In addition to serving as Director of the Cancer Pathology Shared Resource for the OHSU Cancer Institute, Dr. Corless pursues research on immunohistochemical and molecular testing to novel therapeutic targets. He has co-authored dozens of groundbreaking scientific papers concerning the mutations and cell-signalling paths involved in GISTs and the response of GISTs to drug treatments. You can learn more about Dr. Corless and his work at the Heinrich-Corless Laboratories website
ANSWER FROM DR. CORLESS:
"The objective of a biopsy is to obtain enough tissue/cells to make or confirm a diagnosis of GIST (or perhaps to rule it out). Obviously, pathologists are the ones who make this determination. Biopsies can be guided by a CT-scan or abdominal ultrasound to sample tissue from the tumor." [Fine-needle biopsies obtain less tissue than core-needle biopsies, but the needle path is more protected from biopsy-tissue contact using the core-needle technique.]
"I want to emphasize that the controversy over the use of a needle biopsies centers solely on new, primary tumors for which GIST is on the list of possibilities. On the one hand, such a biopsy may lead to a diagnosis of lymphoma, which is generally not treated by surgery (thus sparing the patient a procedure). On the other hand, a needle biopsy could allow GIST cells to seed the abdominal cavity. I am not aware of any hard data on exactly how big this risk is."
"The ACS site that you mention is probably quoting the NCCN guidelines that were released in mid 2004. The 2004 guidelines have been updated, but you can link to the current 2006 NCCN Soft Tissue Sarcoma Guidelines.
Concern has been raised by a number of physicians in the GIST field as to whether it is safe to put a needle into a large tumor by way of the abdominal skin (thus crossing the abdominal cavity). There is a theoretical risk of allowing some tumor cells to be pulled out along the shaft of the needle when it is withdrawn, allowing them access to the abdominal cavity. Of course, this is primarily a concern with regard to primary tumors. If there is already tumor spread within the abdomen or to the liver, the issue is moot. The NCCN guidelines have taken the conservative stance that such trans-abdominal biopsies are not a good idea when evaluating a new, primary GIST. But we really don't know how significant the risk is."
"The other comment that I would make on this topic is that it is quite safe to evaluate GISTs by way of an endoscope. With the assistance of an ultrasound device passed through the endoscope, it is possible to do a needle biopsy of a GIST from inside the stomach, small bowel (in some cases) or colon. Such biopsies do not pose a risk of spreading tumor into the abdominal cavity, because the needle is simply pulled back inside the gut and drawn out through the endoscope. Quite amazing when you think about it! We've even done mutation analyses on such specimens.
So, although the use of endoscopy to biopsy GISTs is quite safe, not all tumors can be approached this way."
"In my view, the best way to deal with a new case of possible GIST is a team effort between the surgeon, radiologist and gastroenterologist; collectively, they can decide what is the best and safest way to get diagnostic tissue."
FOR FURTHER INFORMATION...
GSI thanks Dr. Corless for the information he provided above. If you want to read further, here are some sources.
NCCN Sarcoma Guidelines state that biopsy is rarely needed for resectable retroperitoneal sarcoma of any type (not just GIST), and that CT-guided core biopsy is recommended if needed. One reason a biopsy might be needed is if neo-adjuvant therapy (such as Gleevec for GIST) is being considered for an unresectable or marginally resectable tumor (to shrink it first).
The NCCN Task Force Report on Optimal Management of Patients with GIST further states that pre-operative biopsy may not be appropriate if the tumor is easily resectable.
Both NCCN documents are found at http://nccn.org
Click here for the link to the American Cancer Society write-up on diagnosing GIST.
Here are links to general descriptions of biopsy procedures.