Sentinellymph node biopsy is the preferred criteria for axillary staging in breastcancer. A sentinel lymph node is described as the first lymph node in aregional basin that receives lymphatic drainage from the site of the primarytumor. In patients with positive axillary lymph nodes, regional control is mostimportant. ALND can achieve both goals but it is recognized as the most morbidpart of breast cancer surgery. SLNB is a substitute to ALND for staging axillain early breast cancer patients with minimal morbidity.
SLN biopsy is a trustworthy, mechanism for standard levelstandard level I/II axillary dissection. The main component the lymphatic mapping that permits the axillary nodesto assess. Occurrence of node toattain metastasis, regional metastatic disease needs to exist. The SLN reflects the histopathological status of the whole axilla,therefore if finding of the SNL is negative, that indications the nodal basinto be negative as well. In 1992,Morton’s group tested the SNL biopsy with more than 500 melanoma patients.Successfully removing the sentinel node, along with the remaining regionallymph nodes. 54 Thepathology of the sentinel node claimed to show 99% accuracy of remainingregional nodal status. Other institutions authorized complete lymphadenectomyand histopathological examination, addition to follow-up to distinguishpotential recurrences in undissected nodal basins shadowing a negative sentinelnode biopsy.
55-57 Giuliano et al. 19 alsoillustrated the initial experience with SNL biopsy for breast cancer, by usingvital blue dye injection, it was proven by histopathological examination of thenon-SLNs. 58 By using atechnetium sulfur colloid injection and operating a hand-held ?-probe fordetection, Krag et al. 22 stated aprimary series of breast cancer SLN biopsies.Lately, several randomized clinical trials theSOUND 59 and NCT 01821768 60 randomized amongst SNB and non-SNBfollowing negative US/FNA findings including the early breast cancer patients.Such trials revealed the prerequisite for SNB in cases with negative ultrasound(US)-guided fine-needle aspiration cytology (FNA) of doubtful LNs. Numerousother investigative tools were used to identify negative axillary node (cN0)status in these trials.
For example: The palpation of the axilla, the USimaging using or computed tomography (CT), or intervention with FNA forsuspicious LNs. Hence, a significant thought for an exclusion of SNB or ALNDdiffers on an extremely accurate preoperative staging for axillary LNsassessment. Ourresults show that although core biopsy had greater sensitivity than FNA indetecting metastasis, it could not approach statistical significance, perhapsmainly owing to the lesser patients. Our study also reported three vitalfindings. Primary, the high accuracy rate of CNB between preoperativediagnostic axillary staging and final histological findings, representing thesuperiority of CNB over FNA. Following, the objective predictors of decisivepathological negative node status were related with the clinicalcharacteristics of breast cancer and the investigative means used to assess theaxillary LNs. Lastly, our study also found that CNB for axillary staging interms of safety and simplicity was parallel to FNA procedure. In this current study, we found out during the USfindings, abnormal LNs among the breast cancer patients while a negative CNBresult had a comparatively lower rate of positive LNs and a lower rate ofnon-SLN metastasis than patients with a negative FNA.
The accuracy of FNA andCNB compared to the final histological diagnosis of LNs was 90.8% in FNA while96.2% in CNB. Precisely, Sensitivity was 76.0% in FNA and 90.0% in CNB andpositive predictive value of FNA 87.
2% and CNB 94.2% (Table 2). Our studycomprised several experienced surgeons and allowed a variety of samplingdevices to simulate actual clinical practice. While axillary node FNA istechnically easy to perform for one skilled in image-guided procedures, the surgeonsmust obtain an aspirate that is both adequate in the amount of material and atthe same time not overly bloody, to enable an optimal interpretation.
It is unclearwhy there were fewer false negative results when multiple FNA entries wereachieved, as the total number of needle excursions likely did not differ greatly.Maybe the chance of obtaining a better sample was increased by using different entrysites or obtaining less blood mixed with cells from the node. The number ofslides used, the actual number of excursions and length of procedure were notrecorded, which could have affected the results. In some institutions, apathologist is present when cytologic samples are obtained and can requestadditional sampling if the specimen is estimated suboptimal; the presence of apathologist at the time of sampling could have improved the yield from FNA. Inour institution, immunostains may be used to aid in interpretation when FNAalone is performed. Our pathologists have extensive experience in cytopathologybut in this study, there were no immunostains used in the cytologic evaluation;because the pathologists knew that additional tissue would be studied by corebiopsy, a reason that may have decreased the sensitivity of FNA. Amongstpatients with breast cancer, US-guidedcore needle biopsy of axillary lymph nodes can yield a high accuracy rate withno substantial complications.
Anideal lymphatic tracer must have size (in the range of 50–200 nm) small enoughto pass the lymphatic capillaries and migrate promptly to the SLNs, still adequatelybig enough to retain in the sentinel nodes long enough for imaging and SLNsidentification without prematurely transferring to higher tier nodes. 61-63 Nano-sized carbon particleswith an average diameter of 150 nm, which ensures that these particles passthrough the lymphatic capillaries and accumulate in the lymph nodes long enoughfor the SLNs to be identified during surgery. In contrast, the blue dyemolecules are rather small (<2 nm), and thus they can quickly transportthrough the sentinel lymph nodes, causing color fading of blue dye and a highpossibility of false negative rate. 64Hence, it should be easierapplying carbon nanoparticles than using the blue dye in SLN biopsy due to itslonger presentation time in SLNs. This has important clinical implications.
Because the dyes quickly diffuse through SLNs, a ‘blue’ node may not be thetrue sentinel node, but instead a level II or even level III, non-sentinelnode. So, non-sentinel lymph nodes might be incorrectly diagnosed as SLNs,causing more nodes to be excised than needed and a false-negative staging. Carbonnanoparticles are most expected to reduce this false negative detection byretaining in the SLNs. Carbon nanoparticles detection is more dependable andassuring than blue dye because the dye distribution in SLNs subsequent to injectionof carbon nanoparticles is more liable to last for longer time. 35 We used both Carbon Nanoparticle suspension injection andradioisotope in our patients and it helped us to find accurate SLNs during FNAand CNB under ? probe followed by ultrasound which helped during surgery tolocate SLN. Additionally, gamma probehas its radioactive content that provides the surgeon a sense of focus andallows detection of non-visible nodes. There isincreasing evidence in the literature to support better results when bothdetection methods are combined, compared with the use of these techniquesalone.
28Cserni and associates 65 reported that combined technique has advantages likehigher identification rate, higher accuracy level, and a lower false negativerate. In our study core biopsy had no moremorbidity than FNA, even with the largest gauge device. Use of a biopsy devicewith a nonthrow option should diminish the chance of vascular injury.Nevertheless, patients whose suspect node was immediately adjacent to a vesselor profound and difficult to access were not asked to participate in the studyand hence were not subjected to core biopsy. Despite the statisticallysignificant difference we observed in the number of patients reporting painbeing greater during core than FNA, the majority of patients tolerated the painequally well during both procedures, and we do not believe this should be afactor in deciding which procedure to perform. Both FNA and core biopsy wereleast sensitive when the node appearance was least abnormal. This can be due todifficulty in choosing the appropriate node for sampling or due to smallermetastatic deposits in the sampled node.
Limitations of our study included its smallsize, in particular, the small size of subgroups of needle types and number ofsamples obtained. Although there may have been some selection bias due toexcluding patients with nodes not suited to a core biopsy, the goal of thestudy was to compare the two methods when both were possible. In all cases, thecore biopsy was performed after the FNA, with additional lidocaine, which mayhave minimized the pain associated with core biopsy. FNA was always performedfirst because of concern that core biopsy might cause sufficient bleeding tohave to abort the second sampling procedure, but the bleeding was not asubstantial problem. An additionallimitation of our study was some of the false negative biopsy results canprobably be accredited to a failure to identify the SLN under the US.
Earlierreports have shown that the SLN was not always targeted at preoperativeUS-guided biopsy subsequently only 64–78% of the LNs that underwent CNBcorresponded to the SLN removed at surgery. 66,67 Previous studies reported that morphologically normal-appearingnodes had lymph node metastases with positivity ranging from 26 to 52%. 48,50,68,69 In our routine daily practice, we believe that thecombined procedure helps to retain experience in the cytology of solid organsand provide maximum sensitivity and specificity. FNAB and CNB techniques shouldnot be considered mutually exclusive, but as two different diagnosticmodalities that complement one another. 70-73 (Table 4) Summarizes the benefits ofthe combined procedure.
Therefore, and as shown by other investigators, theutilization of both aspirate smears and core tissue biopsy material arecomplementary and have added value compared to either one alone. 70-72 An earlier study which was held in 2016included new primary breast cancer cases on the ipsilateral side that weresubjected for the US guided axillary biopsies in a two-year time duration withresults compared to the decisive histopathology from SLNB or ANC. They wereable to find the association for CNB but not statistically suggestive in favorof either method.74According to the latest review, it didn’t report absolutesuperiority of CNB over FNAC while reporting the experiences of the cytopathologiststo have a likely influence to report the differences in the procedures.75 Undoubtedly, this explains that the operator’s skillsand techniques are likely to have an important part. A retrospective studyreported 69.1% sensitivity of CNB and specificity of 100% (n = 650) as anoutcome, 33% of patients didn’t undergo SLNB. 76The mainfocus of our research was tissue sampling techniques guided by ultrasound hencewe included, only consecutive cancer patients who underwent US scans which introduceda selection bias.
To conclude, in cases of newly diagnosed invasive breastcancer patients when accurate preoperative staging of the axilla is needed. TheCNB should be encouraged as the first line biopsy method as CNB is moresensitive than FNAB.