Document Type


Publication Date



Background: Sentinel lymph node (SLN) mapping and biopsy have become the standard of care for axillary staging of a breast cancer patient. Higher rate of use has led to the identification of an absolute failure rate and a subset of patients who fail lymph node mapping due to causes independent of the procedure. Failure of lymph node mapping leads to more invasive procedures with higher morbidity. Body mass index has been associated with higher SLN failure rate. Methods: Retrospective study of patients who underwent Sentinel lymph node procedures between October 2003 to June 2008 at University of New Mexico. After internal board review, electronic medical database was used to identify patients within study parameters, and to collect data needed for BMI calculation and SLN procedure details. Results: BMI of greater than 30 had a failure rate of 44.83% with blue dye and 13.33% with technetium collide tracer (p value 0.05 and 0.04). BMI less than 30 had a failure rate of 30.56% for blue dye and 4.63 for technetium. Odds of success for blue dye were 0.5 and 0.3 for technetium for patients with BMI greater than 30. Failure rates for palpation of sentinel node 41.47% and 50% for BMI less than 30 and greater than 30 respectively. Discussion: Study identified higher failure rate in obese patients compared to overweight to normal weight patients. Study indicates higher failure rates in obese patients than the reported absolute failure rate of SLN mapping. Conclusion: Obesity increases the failure rate of both blue dye and technetium colloid. Obesity does not contribute to the failure to palpate a sentinel node. Obesity alone is not a contraindication for SLN mapping suing Technetium or blue dye, but surgeon must be aware of higher failure rate in obese patients and change their procedural methods to accommodate.