The SLN can be defined as the first lymph node that receives the lymphatic drainage of the region containing the primary tumour. SLNB is now a standard technique that is applied to early-stage breast cancer with clinically negative axillae; it can predict the presence of metastasis with a high rate of accuracy [4, 15]. Technically, SLNB can be applied using only dye, only radioactivity, or a combination of these two methods. All three methods can reportedly be applied with high rates of detection, sensitivity, and accuracy and with acceptable false-negative rates .
Performance of SLNB with blue dye only is a more inexpensive and easier technique to apply compared with the combination method because it does not require involvement of the nuclear medicine department. In studies using these methods, the success rates of finding SLNs are reported to be 41% to 100% with the dye-only method, 69% to 100% with the radioisotope-only method, and 76% to 100% with the combination method [16–18]. Kim et al. investigated 69 clinical studies performed between 1970 and 2003 and calculated a false-negative rate of 10.9% with the dye-only method, 8.8% with the radiocolloid-only method, and 7% with the combination method in their meta-analysis . The relatively low success rates reported in the literature for SLNBs performed with the dye-only method can be explained by the fact that in these studies, the initial SLNB was performed with the dye-only method .
When comparing the dye-only and combination methods, Radovanovic et al. reported that in their prospective randomised study with 150 patients, although there was no significant difference in the number of lymph nodes removed, the combination technique was superior in its negative predictive value and overall accuracy rates. In this study, the negative predictive value was 86.9% in the dye-only group and 95.3% in the combination group; the overall accuracy was 68% in the dye-only group and 83% in the combination group . Varghese et al., in a prospective randomised study with 329 patients, reported similar results for the two methods and stressed that in institutions without nuclear medicine capability, SLNB can be performed using the dye-only method. and Meyer-Rochow et al. reported comparable findings in their randomised study with 104 patients [14, 19]. Koukouraki et al. found that the SLN detection rate was higher with the combination method in their randomised study with 501 patients, but Kern et al. reported a high concordance between the two methods in their study with 185 patients, and similar numbers of SLN detection ratios were obtained with both techniques [12, 20].
Three reviews have been published regarding SLNs: in 2006, Steven et al. reported that all of the methods could be performed with similar SLN detection and false-negative rates when they were performed by experienced surgeons; in 2007, Sato et al. reported that the dye and combination methods returned the same results and that the radioisotope added extra cost and potential radioactivity damage risk; and in 2008, Collins reported that radiopharmaceutical-only SLNB was superior to dye-only SLNB but that only the combination method had the potential to maximise the correct staging [5, 6, 9].
In all of the above-mentioned studies, SLNB was performed by two surgical teams and, as required by the randomisation, the dye-only group and the combination group comprised different patients. Because of this, the surgeon and patient factors could not be equalised in these studies. Our study design is novel because these two factors were completely equalised by having the same surgeon perform all of the surgeries and by applying both techniques to the same patient group.
In our study, as a result of adding the radioisotope to the blue dye, 34 additional lymph nodes were excised from 42 patients; this number is quite high compared with other studies in the literature. In addition, the average number of lymph nodes that were identified for removal by the combination method was significantly higher than the number of lymph nodes removed by the dye-only method. Despite this high additional lymph node dissection, the lymph nodes first removed from the axilla using the dye-only method, the hot-only nodes that were removed later, and the stained-hot nodes that were not missed during the first stage were 100% concordant in terms of metastasis and did not change the decision to perform axillary curettage.
The mean age was low in our present study because of the limited number of patients. In general, the mean age of the patients who undergo breast cancer surgeries in our institution is higher. Furthermore, in Turkey, the mean age of patients with breast cancer is correlated with world numbers. We believe that the low mean age in our present study was incidental.
SLNB may be difficult in obese patients. In the present study, we did not evaluate body mass indices, which is a limitation.
Although the addition of the radioisotope tracer method increases the number of lymph nodes excised from the axilla, it was not found to be superior to the dye-only method with respect to the SLNB detection rates and determination of axilla positivity; furthermore, it did not change the ALND decision for any of the patients. In this context, when the side effects of the combination method (which are perhaps due to the potentially unnecessary removal of additional lymph nodes) are taken into account, we conclude that SLNB should be performed with the dye-only method. The present study is an original surgical method performed by the same surgeon without the need for a control group. Some authors believe that this method does not bring any additional data to the literature and may result in excessive lymph node dissection.