Introduction: Sentinel lymph node dissection (SLND) is becoming a recognized technique for accurately staging patients with breast cancer. Its success in patients with large tumors or prior excisions has been questioned. The purpose of this study was to evaluate the effect of biopsy method, excision volume, interval from biopsy to SLND, tumor size, and tumor location on SLND success rate.
Methods: Consecutive patients who underwent SLND followed by completion axillary lymph node dissection from October 1991 to December 1995 were analyzed. Included were cases performed early in the series before the technique was adequately developed. Excision volume was derived from the product of three dimensions as measured by the pathologist. Two end points were analyzed: sentinel node identification rate and accuracy of SLND in predicting axillary status. Univariate analyses using chi2 or Fisher's exact test for categorical variables and Wilcoxon rank sums for continuous variables were performed. Multivariate analysis was performed using logistic regression.
Results: There were 284 SLND procedures performed on 283 patients. Median age was 55 years. The most recent biopsy method used before SLND was stereotactic core biopsy in 41 (14%), fine-needle aspiration in 62 (22%), and excision in 181 (64%) procedures. The mean excision volume was 32 ml with a range of 0.3-169 ml. The mean time from biopsy to SLND was 17 days with a range of 0-140 days. The mean tumor size was 2.0 cm (15 Tis [5%], 184 T1 [65%], 72 T2 [25%], and 13 T3 [5%]). Tumors were located in the outer quadrants in 74%, the inner quadrants in 18%, and subareolar region in 8%. The sentinel node was identified in 81%, and 39% had metastases. There were three false-negative cases early in the series. Sensitivity was 97%, and accuracy was 99%. Negative predictive value was 98% in cases in which the sentinel node was identified. On the basis of biopsy method, excisional volume, time from biopsy to SLND, tumor size, and tumor location, there was no statistically significant difference (P>.05) in sentinel node identification rate or accuracy of SLND.
Conclusions: SLND has a high success rate in breast cancer patients regardless of the biopsy method or the excision volume removed before SLND. In addition, the interval from biopsy to SLND, tumor size, and tumor location have no effect on the success rate of SLND, even in this series which included patients operated on before the technique was adequately defined. Patients with breast cancers located in any quadrant and diagnosed either with a needle or excisional biopsy could be evaluated for trials of SLND.