Rand Jordan Stack MD, Abstract Co-Author: Nothing to Disclose

Munir Ghesani MD, Presenter: Nothing to Disclose

Ramesh Gadiraju MD, Abstract Co-Author: Nothing to Disclose

Sentinel lymph node biopsy (SLNB) is a minimally invasive technique for identifying lymphatic metastasis of breast cancer at the time of lumpectomy. Intradermal injection of radiotracer is the first step of (SLNB). This injection is painful for the patient: in one published study, patients rate the pain of the SLNB injection 6 on a scale of 10. Recent studies have described techniques for reducing the pain of the SLNB injection by pretreatment of the skin with topical anesthetic (EMLA) or by mixing the radiotracer solution with lidocaine. A modified technique for SLNB injection is described which patients find less painful and has the benefit of a success rate at least as high as previously published techniques.

Much of the pain from SLNB injection results from physical trauma to the dermis related to the volume of material introduced into the layers of the skin. In this study, the solution used for SLNB injection was modified to decrease the volume of the intradermal injection. This was achieved through elution of the radiotracer in a smaller volume of liquid. A total of 100 uCi [3.7Mbq] of Tc99m sulfur colloid, 0.22 micron filtered was suspended in a volume of 0.1 cc of normal saline for same day surgery and a total of 500 uCi [18.5mBq] of Tc99m sulfur colloid, non filtered was suspended in a volume of 0.1 cc of normal saline for next day surgery. The dose was administered as a single intradermal injection in the periareolar distribution in the upper outer quadrant adjacent to the areola.

The sentinel lymph node was successfully identified based upon radiotracer uptake in 90% of a series of 100 patients injected with this technique. Retrospective review of questionnaires (routinely completed by nuclear medicine patients) regarding discomfort of the injection using the Wong-Baker FACES pain-rating scale (a standardized 10-point Likert scale where 0 is no pain and 10 is the worst pain) 80% of the patients had pain rating between 0-1 and 20% had pain rating between 1-2. None of the patients complained of pain beyond 2.

This technique results in a high success rate for SLNB while simultaneously reducing the pain associated with the procedure.

This technique significantly reduces the pain associated with a procedure performed on many patients undergoing lumpectomy for breast cancer.

Stack, R, Ghesani, M, Gadiraju, R, Reduction of Pain Associated with Sentinel Lymph Node Biopsy Radiotracer Injection through Modification of the Concentration of Radioisotope.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9004277.html