Sentinel lymph node biopsy is the preferred criteria foraxillary staging in breast cancer.
A sentinel lymph node is described as thefirst lymph node in a regional basin that receives lymphatic drainage from thesite of the primary tumor. In patients with positive axillary lymph nodes,regional control is most important. ALND can achieve both goals but it isrecognized as the most morbid part of breast cancer surgery. SLNB is asubstitute to ALND for staging axilla in early breast cancer patients withminimal morbidity.
SLN biopsy is a trustworthy, mechanismfor standard level standard level I/II axillary dissection. The main component the lymphatic mapping thatpermits the axillary nodes to assess. Anoccurrence of a node to attain metastasis, the regional metastatic diseaseneeds to exist. The SLN reflects the histopathological status of the whole axilla,therefore if a 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 clinicaltrials the SOUND 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 US imagingusing or computed tomography (CT), or intervention with FNA for suspicious LNs.Hence, a significant thought for an exclusion of SNB or ALND differs on anextremely accurate preoperative staging for axillary LNs assessment. Our study shows that core biopsy had greatersensitivity than FNA in detecting metastasis, it could approach statisticalsignificance.
Our study also reported three vital findings. Primary, the highaccuracy rate of CNB between preoperative diagnostic axillary staging and finalhistological findings, representing the superiority of CNB over FNA. Following,the objective predictors of decisive pathological negative node status wererelated to the clinical characteristics of breast cancer and the investigativemeans used to assess the axillary LNs. Lastly, our study also found that CNBfor axillary staging in terms of safety and simplicity was parallel to FNAprocedure. In this current study, we foundout during the US findings, abnormal LNs among the breast cancer patients whilea negative CNB result had a comparatively lower rate of positive LNs and alower rate of non-SLN metastasis than patients with a negative FNA. Theaccuracy of FNA and CNB compared to the final histological diagnosis of LNs was90.8% in FNA while 96.
2% in CNB. Precisely, Sensitivity was 76.0% in FNA and90.0% in CNB and positive predictive value of FNA 87.2% and CNB 94.2% (Table2). 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, thesurgeons must obtain an aspirate that is both adequate in the amount ofmaterial and at the same time not overly bloody, to enable an optimalinterpretation. It is unclear why there were fewer false negative results whenmultiple FNA entries were achieved, as the total number of needle excursionslikely did not differ greatly. Maybe the chance of obtaining a better samplewas increased by using different entry sites or obtaining less blood mixed withcells from the node. The number of slides used, the actual number of excursionsand length of procedure were not recorded, which could have affected theresults.
In some institutions, a pathologist is present when cytologic samplesare obtained and can request additional sampling if the specimen is estimatedsuboptimal; the presence of a pathologist at the time of sampling could haveimproved the yield from FNA. In our institution, immunostains may be used to aidin interpretation when FNA alone is performed. Our pathologists have extensiveexperience in cytopathology but in this study, there were no immunostains usedin the cytologic evaluation; because the pathologists knew that additionaltissue would be studied by core biopsy, a reason that may have decreased thesensitivity of FNA. Amongst patients with breast cancer, US-guided core needlebiopsy of axillary lymph nodes can yield a high accuracy rate with nosubstantial complications.
The size of a best lymphatic tracershould be (in the range of 50–200 nm)big enough to remain in the sentinel lymphnodes, small enough to allow its entry into the lymphatic capillaries whilelong enough for proper SLN visualization and imaging without being transferredto the higher tier nodes early.61-63 For the SLNs to be properly recognizedduring the surgical procedure, the Nano-sized carbon particles with a diameterof 150nm pass easily through the lymphatic capillaries and also allowsaccumulation in the lymph nodes for the longer duration. In comparison, themolecules of blue dyes are pretty small (<2 nm), allowing the easy shippingacross the sentinel lymph nodes, which has the highest possibility of the falsenegative rate because of the rapid washing of the blue dye.
64The carbon Nanoparticleshave an important application clinically. Thus, it is far better to use carbonnanoparticles than the blue dye in SLN biopsy because it is preserved for alonger time in SLNs. The blue dyes quickly diffuse through SLNs and may beretained in the level II or even level III or even on non-sentinel lymph nodesinstead of being retained in the true sentinel lymph nodes.
As a result, duringthe biopsy of SLNs using the blue dye, there might be an incorrect diagnosis,leading to unnecessary excision of more nodes and a false-negative staging.Carbon nanoparticles are retained in the SLNs thus reducing the false negativedetection. In comparison to the blue dye, Carbon nanoparticles detection ismore reliable and convincing because the dye is more liable to last for alengthier time. 35 We usedboth Carbon Nanoparticle suspension injection and radioisotope in our patientsand it helped us to find accurate SLNs during FNA and CNB under ? probefollowed by ultrasound which helped during surgery to locate SLN. Additionally, gamma probe has itsradioactive content that provides the surgeon a sense of focus and allows detectionof 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 more morbidity than FNA, even with thelargest gauge device.
Use of a biopsy device with a nonthrow option shoulddiminish the chance of vascular injury. Nevertheless, patients whose suspectnode was immediately adjacent to a vessel or profound and difficult to accesswere not asked to participate in the study and hence were not subjected to corebiopsy. Despite the statistically significant difference we observed in thenumber of patients reporting pain being greater during core than FNA, themajority of patients tolerated the pain equally well during both procedures,and we do not believe this should be a factor in deciding which procedure toperform.
Both FNA and core biopsy were least sensitive when the node appearancewas least abnormal. This can be due to difficulty in choosing the appropriatenode for sampling or due to smaller metastatic deposits in the sampled node. Limitations of our study included its small size, in particular, thesmall size of subgroups of needle types and number of samples obtained.Although there may have been some selection bias due to excluding patients withnodes not suited to a core biopsy, the goal of the study was to compare the twomethods when both were possible. In all cases, the core biopsy was performedafter the FNA, with additional lidocaine, which may have minimized the painassociated with core biopsy. FNA was always performed first because of concernthat core biopsy might cause sufficient bleeding to have to abort the secondsampling procedure, but the bleeding was not a substantial problem. Anadditional limitation of our study was some of the false negative biopsyresults can probably be accredited to a failure to identify the SLN under theUS. Earlier reports have shown that the SLN was not always targeted atpreoperative US-guided biopsy subsequently only 64–78% of the LNs thatunderwent CNB corresponded to the SLN removed at surgery.
66,67 Previousstudies reported that morphologically normal-appearing nodes had lymph nodemetastases with positivity ranging from 26 to 52%. 48,50,68,69 In our routine daily practice, webelieve that the combined procedure helps to retain experience in the cytologyof solid organs and provide maximum sensitivity and specificity. FNAB and CNBtechniques should not be considered mutually exclusive, but as two differentdiagnostic modalities 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 earlierstudy which was held in 2016 included new primary breast cancer cases on theipsilateral side that were subjected for the US-guided axillary biopsies in atwo-year time duration with results compared to the decisive histopathologyfrom SLNB or ANC. They were able to find the association for CNB but notstatistically suggestive in favor of either method.
74According to the latest review, it didn’t report absolutesuperiority of CNB over FNAC while reporting the experiences of thecytopathologists to have a likely influence to report the differences in theprocedures.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 main focus of our research was tissue sampling techniquesguided by ultrasound hence we included, only consecutive cancer patients whounderwent US scans which introduced a selection bias.
To conclude, in cases ofnewly diagnosed invasive breast cancer patients when accurate preoperativestaging of the axilla is needed. The CNB should be encouraged as the first linebiopsy method as CNB is more sensitive than FNAB.