Subareolar injection may not always identify the same sentinel lymph nodes as peritumoral injection in breast cancer.

Abstract

Abstract Abstract #1022 Background. Sentinel lymph node (SLN) biopsy is widely accepted as a standard surgical procedure for early breast cancer, but the optimal site for injection of mapping tracers is still controversial. We evaluated whether a combination of peritumoral injection and subareolar injection can improve the identification rate of SLN biopsy and decrease the false-negative rate.
 Methods. From August 2006 to April 2008, 155 patients with biopsy-proven operable breast cancer underwent SLN biopsy with peritumoral injection of radioisotope (Tc-99m-phytate) and subareolar injection of blue dye (patent blue dye).
 Results. The overall identification rate for blue and/or radioactive (hot) lymph nodes was 99.4% (154/155); the identification rate of blue-dyed lymph nodes was 98.1% (152/155) and of hot lymph nodes was 96.8% (150/155). A total number of the excised SLNs were 379 in these 154 patients, and the average number of SLNs in each patient was 2.4 (range, 1-9). The average number of SLNs was 2.0 (range, 1-8) for blue dye and 1.9 (range, 1-6) for radioactive (hot). Two hundred twenty-six nodes (59.6%) were blue and hot, while 79 were blue-only and 74 were hot-only. Consequently, no concordance between the hot node and the blue node was found in 14 of 154 patients (9.1%). Eight of these 14 patients had separate blue-only nodes and hot-only nodes (so-called sequential mismatch). Four patients had SLNs identified by blue dye only, whereas 2 patients had SLNs localized solely by radioisotope labeling. On the other hand, metastatic disease was identified in SLNs of 40 of 154 patients (26.0%). A number of positive SLNs were 55 in these 40 patients, where 34 nodes (61.8%) were blue and hot, 9 were blue-only and 12 were hot-only. Among these 40 patients, 30 patients (75.0%) had blue and hot positive SLN. Four patients had blue-only positive SLN and 4 patients had hot-only positive SLN. Two patients had separate blue-only positive SLN and hot-only positive SLN. The SLN was the only positive node in 24 of the 41 positive SLN mapping (60%). Consequently, the false-negative rates were 9.8% (4/41) for peritumoral injection and 9.8% (4/41) for subareolar injection. There were no significant differences between peritumoral and subareolar injection. However, both injection methods complemented each other, thereby decreasing the false-negative rate to 0%. It is important to note that metastatic disease was identified by peritumoral injection in 4 patients in which the SLN was hot-only. At a median follow-up of 10.5 months (range, 2-22 months), there were no axillary recurrences in any of the 155 patients.
 Conclusions. Subareolar injection may not always identify the same SLN as peritumoral injection. Subareolar injection of blue dye and peritumoral injection of radioisotope improves the identification rate of the SLN and decrease the false-negative rate of SLN biopsy. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1022.