br The best method to map axillary positive lymph nodes
The best method to map axillary positive SP-600125 nodes remains a question. The positioning of a metallic clip using ultrasound guidance into a positive node is simple and can be performed by an experienced surgeon or radiologist. The main difficulty here is the identification and localization of the clipped node after NAC. A hyperechoic tissue marker could be easily visualized using ultrasound in a pathologic, enlarged, hypoechoic lymph node; however, after NAC completion and lymph node regression, this can be very difficult or even impossible. Various tissue markers with better ultrasound visualization have been proposed but no one is the “perfect one.” Furthermore, the placement of hook wires into the axillary cavity for clipped node localization, especially if 2 or more nodes must be localized, causes patient discomfort. Use of a radioactive seed is more sophisticated, but also more expensive, and legal issues might arise if seed placement precedes NAC. ALN tattooing is a simple and less expensive method. Tattoo ink remains in site for a long period of time (in our study, up to 231 days) with no necessity of extra radiological imaging or nuclear medicine procedures to localize it. IR of marked nodes is similar to that of other methods. In our study, the intraoperative IR of all marked nodes was 94.6%, but the final achievement of surgical retrieval of all marked nodes was 98.6%. The black pigment in axilla was easily identified in most cases. Sometimes Ioannis Natsiopoulos et al
the blue color of methylene blue was overlaid by black pigment; however, the blue-colored efferent lymphatic vessels indicated the presence of a sentinel node. After adequate experience was gained, the distinction between blue and black pigment was straightforward. Furthermore, the use of the radiotracer technique for SLN mapping diminishes the importance of color overlap, because most SLNs are identified according to the radioactive counts and not according to the blue dye uptake. Blue-dyed lymph nodes identification is important in case of negative lymphoscintigraphy.32 The correspondence between tattooed nodes and SLNs was 75.7%, which indicates that for patients who are cNþ, who become cN0 after NAC, SLNB alone is an inad-equate method of axillary assessment. This is in concordance with the results of Park et al31 (75%) but is in discordance with the results of Choy et al15 (96.3%).
In 45.3% of our patients, final histology revealed black pigment in more lymph nodes than those initially marked. None of those nodes were identified as “tattooed” nodes during surgery and all were included in the “sentinel/no black pigment” group. Black pigment was identified as small foci of black granules. The presence of carbon granules in more nodes than those primarily marked demonstrates the possibility of tattoo ink migration from one node to another. In the study by Choy et al, migration of tattoo ink was observed in 1 of 28 patients.15 In the study by Park et al, the possibility of tattoo ink migration is reported, but detailed data is not provided.31 According to this, identification of black pigment in pathological examination of SLNs is not always evidence of marked node retrieval, especially if black pigment is identified as small foci in the lymph node cortex. Thus, microscopically detected carbon particles in macroscopically non-black nodes should not be considered as evidence of retrieved marked nodes, except the case of extended presence of black pigment in the nodal cortex. Intra-operative identification of all marked nodes using visual inspection is essential and might be sufficient to ensure the accuracy of this method. As a result of tattoo ink migration, a possible disadvantage of this procedure is that, in those cases that tattooed nodes were not identified intraoperatively, it is difficult to confirm their retrieval only using pathological examination.
Careful evaluation of the axilla is critical for patients who undergo NAC, before and after treatment. Physical examination alone has been considered inadequate as an axilla staging assessment, because of its low sensitivity and accuracy. Several studies have reported sensi-tivity and specificity in the range of 25% to 35.5% and 93% to 98.4%, respectively.33,34 Ultrasound combined with needle biopsy (US-NB) is the most common method for axillary evaluation. In a meta-analysis of Houssami et al, pooled estimates for sensitivity, specificity, and positive predictive value of US-NB were 79.6% (95% confidence interval [CI], 74.1-84.2) 98.3% (95% CI, 97.2-99.0), and 97.1% (95% CI, 95.2-98.3), respectively.35 Before NAC, nodes indicative of disease must be biopsied, and every biopsy-positive or biopsy-negative (but indicative of disease) node must be marked. Ultrasound examination and, if necessary, US-NB after NAC is essential to determine if residual disease exists, thus avoiding unnec-essary SLNB and TAD procedures in patients with positive axilla.