A trend analysis of the relative value of blue dye and isotope localization in 2,000 consecutive cases of sentinel node biopsy for breast cancer.

BACKGROUND: Among the advocates of blue dye, isotope, or combined dye-isotope mapping of the sentinel lymph node (SLN) for breast cancer, there is no universal consensus as to which technique is optimal and whether the relative value of each method changes with increasing experience. The objective of this study was to examine the relative contributions of blue dye and radioisotope to successful identification of the SLN as the SLN-mapping technique evolved over our first 2,000 consecutive cases. STUDY DESIGN: Using the first 2,000 consecutive SLN biopsy procedures for breast cancer, performed by eight surgeons (none previously experienced in SLN techniques) at one institution, using a combined technique of blue dye and isotope mapping, we report the institutional learning curve and the relative contributions of dye and isotope to identifying both the SLN and the positive SLN, by increments of 500 cases. RESULTS: Comparing the first 500 with the most recent 500 cases, success in identifying the SLN by blue dye did not improve with experience, although success in isotope localization steadily increased, from 86% to 94% (p < 0.00005). With the increasing success of isotope mapping, the marginal benefit of blue dye (the proportion of cases in which the SLN was identified by blue dye alone) steadily declined, from 9% to 3% (p = 0.0001). Parallel to this trend, the proportion of positive SLNs identified by blue dye did not change with experience (89% to 90%), but isotope success steadily increased, from 88% to 98% (p = 0.0015). The proportion of positive SLNs identified by blue dye alone declined from 12% to 2% (p = 0.0015). CONCLUSIONS: Using a combined technique of blue dye and radioisotope mapping, and with refinement of the radioisotope technique, we report 97% success identifying the SLN. Although we continue to recommend the use of both methods in SLN mapping for breast cancer, we observe with experience a declining marginal benefit for blue dye.

Intradermal isotope injection is superior to intramammary in sentinel node biopsy for breast cancer.

BACKGROUND: The optimal sentinel lymph node (SLN) biopsy technique remains undefined in breast cancer. Injecting radiotracer or blue dye by a variety of routes seems to stage the axilla with comparable accuracy, and we have hypothesized that the dermal and the parenchymal lymphatics of the breast drain to the same SLN in most patients. Two previous studies from our institution support this concept: (1) a single-surgeon series of 200 consecutive SLN biopsy procedures demonstrating a high dye-isotope concordance for both intradermal (ID) and intraparenchymal (IP) isotope injection, and (2) a series of 100 procedures validated by a backup axillary dissection (ALND) in which the false-negative rate following ID isotope injection was comparable to that of our previous results with IP injection. Here, we directly compare the results of SLN biopsy using either ID or IP isotope injection for our entire experience of SLN biopsy procedures in which a backup ALND was done. METHODS: This is a retrospective, nonrandomized study of 298 clinical stage I to II breast cancer patients having SLN biopsy with a backup ALND planned in advance, comparing the results of ID (n = 164) and IP (n = 134) isotope injection. All patients had IP injection of blue dye. Endpoints included (1) successful SLN identification, (2) false-negative rate, (3) dye-isotope concordance, and (4) the SLN/axillary background isotope count ratio. RESULTS: ID isotope was more successful than IP, identifying the SLN in 98% versus 89% of cases, respectively. False-negative results (4.8% vs 4.4%) and dye-isotope concordance (92% vs 93%) were comparable between the 2 groups, and SLN/axillary background isotope count ratios were significantly higher with ID than with IP injection (288/1 vs 59/1). CONCLUSIONS: ID isotope injection identifies the SLN more often than IP, stages the axilla with comparable accuracy, and is associated with higher levels of SLN isotope uptake. The dermal and parenchymal lymphatics of the breast drain to the same axillary SLN in most breast cancer patients, and ID isotope injection is the procedure of choice in this setting.