Multicenter trial of sentinel node biopsy for breast cancer using both technetium sulfur colloid and isosulfan blue dye

Objective To determine the factors associated with false-negative results on sentinel node biopsy and sentinel node localization (identification rate) in patien ts with breast cancer enrolled in a multicenter trial using a combination t echnique of isosulfan blue with technetium sulfur colloid (Tc99). Summary Background Data Sentinel node biopsy is a diagnostic test used to detect breast cancer meta stases. To test the reliability of this method, a complete lymph node disse ction must be per formed to determine the false-negative rate. Single-insti tution series have reported excellent results. although one multicenter tri al reported a false-negative rate as high as 29% using radioisotope alone. A multicenter trial was initiated to test combined use of Tc99 and isosulfa n blue. Methods Investigators (both private-practice and academic surgeons) were recruited after attending a course on the technique of sentinel node biopsy. No inves tigator participated in a learning trial before entering patients. Tc99 and isosulfan blue were injected into the peritumoral region. Results Five hundred twenty-nine patients underwent 535 sentinel node biopsy proced ures for an overall identification rate in finding a sentinel node of 87% a nd a false-negative rate of 13%. The identification rate increased and the false-negative rate decreased to 90% and 4.3%, respectively, after investig ators had performed more than 30 cases. Univariate analysis of tumor showed the poorest success rate with older patients and inexperienced surgeons. M ultivariate analysis identified both age and experience as independent pred ictors of failure. However, with older patients, inexperienced surgeons, an d patients with five or more metastatic axillary nodes, the false-negative rate was consistently greater. Conclusions This multicenter trial, from both private practice and academic institution s, is an excellent indicator of the general utility of sentinel node biopsy . It establishes the factors that play an important role (patient age, surg ical experience, tumor location) and those that are irrelevant (prior surge ry, tumor size, Tc99 timing). This widens the applicability of the techniqu e and identifies factors that require further investigation.