Sentinel lymph node biopsy often is performed before or during breast cancer surgery to help figure out if the cancer has spread to nearby lymph nodes. The first step in sentinel lymph node biopsy is injecting a dye or radioactive tracer liquid (or both) into the nipple area. If you're awake during the procedure, this injection can be painful.
The study reviewed here found that adding the local anesthetic lidocaine (a numbing medicine) to the tracer liquid can reduce pain during and after the injection. The lidocaine causes few side effects and doesn't interfere with the procedure's success.
In this study, 140 women who were going to have sentinel node biopsy got either a lidocaine cream (a topical anesthetic) applied to the skin to reduce pain or a placebo cream (a "dummy" cream). Then the women were split into three groups:
The women who got lidocaine mixed in with the tracer injection had much less pain than women who didn't get lidocaine mixed in the injection. The lidocaine cream topical anesthetic reduced the pain a little, but not as much as having lidocaine mixed in the injection.
The sentinel lymph node is the lymph node that would first catch any fluid and cancer cells coming from the breast area. The idea behind sentinel node biopsy is if the sentinel node is identified, removed, and evaluated as free of cancer, then all other lymph nodes also are likely to be free of cancer. This means more lymph node surgery usually can be avoided.
The first step in sentinel node biopsy is to figure out which node is the sentinel node. A common way to do this is to inject a radioactive tracer liquid into the breast tissue. A special instrument then tracks the path of the radioactive liquid as it moves through the breast tissue to see which lymph node it travels to first. That node is the sentinel node. The surgeon then removes the sentinel node (and sometimes other lymph nodes that are very close to it) and sends it out for evaluation. The sentinel node is examined in the lab by a pathologist to see if cancer cells are in the node. If cancer cells are present, surgery to remove other lymph nodes in the area usually is done later (called axillary lymph node dissection). But if the sentinel node is "clean" then more lymph node surgery usually isn't done.
If your doctor is planning to do a sentinel node biopsy as part of your evaluation before surgery, you might want to ask if you can have an anesthetic medicine such as lidocaine mixed in with your injection. Anything you and your doctor can do to make your experience more comfortable is part of taking the best care of you and is worth asking for.
You can learn more about sentinel node biopsy in the Breastcancer.org Lymph Node Removal section.
Adding the anesthetic lidocaine to radioisotope injections significantly reduced pain without compromising the efficacy of sentinel lymph node mapping, according to the results of a randomized controlled trial.
Pain scores immediately after subareolar injection were 6.0 on a 10-point scale with standard care, which includes only topical lidocaine, but only 1.6 with a lidocaine injection (P<0.0001), according to Col. Alexander Stojadinovic, MD, of Walter Reed Army Medical Center, and colleagues.
Lymph node identification rates were no different across treatment groups (P=0.56), nor were there any adverse events associated with lidocaine injection, they reported online, ahead of print, in the September issue of The Lancet Oncology.
The conclusion, according to Stojadinovic's group: lidocaine in the radiocolloid preparation "should be considered a new standard of practice."
Hiram S. Cody III, MD, of Memorial Sloan-Kettering Cancer Center, agreed, noting that this is an issue that has received short shrift in the surgical community.
"All of us who use technetium-99m-sulfur colloid are well advised to add lidocaine to our injection protocols; many patients will benefit," he wrote in an accompanying reaction article.
Among the many approaches to sentinel lymph node biopsy, subareolar injection is quick and effective without requiring image guidance or overlapping radioactivity.
However, these shallow injections under the skin are more painful than deeper injections into breast tissue, and topical anesthetic doesn't always manage the pain well, the researchers noted.
So, Stojadinovic's group tested pain management strategies in a randomized controlled trial. It included 140 women with painless but biopsy-proven early stage breast cancer who had sentinel lymph node biopsy.
The women were assigned to topical 4% lidocaine cream for the skin of the nipple-areolar complex before subareolar injection of the radiocolloid or a topical placebo cream plus one of the following:
Pain scores immediately after injection varied substantially between groups despite identical injection volumes. Measured on the 10-point Likert scale, they were:
Modifying the pH to a more physiologic level did not alleviate pain compared with standard radiocolloid injection (P=0.10) or lidocaine injection (P=0.95).
Likewise, pain ratings by another scale with sensory, affective, and evaluative descriptors showed a similar pattern (17.5 with topical lidocaine, 15.4 with sodium bicarbonate, 4.6 with lidocaine injection, and 3.4 with sodium bicarbonate plus lidocaine injection, P<0.0001).
Again, bicarbonate held no benefit compared with standard radiocolloid preparation (P=0.37) or lidocaine injection (P=0.87).
Sentinel lymph node detection rates were 96% with topical lidocaine, 97% with sodium bicarbonate, 90% with lidocaine injection, and 90% with sodium bicarbonate plus lidocaine injection (P=0.56). All were comparable to rates reported from other centers.
The study was funded by the U.S. Military Cancer Institute, the Clinical Breast Care Project, and the Army Regional Anesthesia and Pain Management Initiative.
The researchers reported no conflicts of interest. Cody reported no conflicts of interest.
Primary source: The Lancet Oncology Source reference: Stojadinovic A, et al "Standard versus pH-adjusted and lidocaine supplemented radiocolloid for patients undergoing sentinel-lymph-node mapping and biopsy for early breast cancer (PASSION-P trial): a double-blind, randomised controlled trial" Lancet Oncol 2009; DOI: 10.1016/S1470-2045(09)70194-9.Additional source: The Lancet OncologySource reference: Cody HS "Sentinel-lymph-node biopsy for breast cancer: the story is not yet over" Lancet Oncol 2009; DOI: 10.1016/S1470-2045(09)70223-2.
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