Breast cancer is the most frequent cancer diagnosed in women worldwide. In patients with breast cancer, accurate lymph node staging is essential for both prognosis (in case of early-stage disease) and treatment (for regional control of disease)[1]. One of the most accurate prognostic factors in breast cancer is axillary lymph node metastasis. Sentinel lymph node biopsy is a minimally invasive technique to confirm regional lymph node metastasis in cancer patients with less morbidity such as lymphedema, axillary web syndrome, chronic pain, and loss of sensation. The SNB is well known as the gold standard diagnosis for axillary lymph node metastasis inpatient without axillary lymph node metastasis with clinical or radiology tests. Since Krag introduced SNB for breast cancer in 1993, we have found many innovations for this technique. Over the past 27 years, sentinel node biopsy in breast cancer patients has become an exciting research topic. Many studies have shown that SLNB accurately predicts axillary lymph node status and associate with less morbidity than ALND completion[2].

Historically, the concept of a mapping lymphatic drainage began in the 1950s. By the 1970s, it was noticed that some nodes received drainage before others and were termed, the “sentinel node.” Lymphatic mapping with the purpose of discovering the sentinel node was first described in 1992 for cutaneous melanoma with the use of blue dye by the late Donald Morton. Krag et al. then applied sentinel lymph node mapping with injected radiotracer using the gamma probe in the treatment of breast cancer in 1993[3]. In the molecular level, the mechanism that determines sentinel lymph node status involves antigen presenting cells and their ability to uptake macromolecular tracers. Presently, SLNB has become the standard over the axillary lymph node dissection (ALND) in the staging of the axilla for clinically node negative disease because of its accuracy and limited morbidity and invasiveness[4-6].

Present study was conducted for 01 Year at MNJIO & RCC/Osmania Medical College, Hyderabad of oncology and regional cancer centre on 100 cases. The sample was early breast cancer patients that underwent sentinel lymph node biopsy. Then, the tissue was evaluated to find lymph node metastasis. Sixty patients fit into the inclusion criteria participated in the research. Both mastectomy and breast conservation surgery patients were equally eligible with SLNB. All patients undergoing the study gave their informed consent for Methylene blue dye 1% 2.5 cc peri-areolar or combination with 2cc injection peritumoral for tumour with size >3cm and superolateral position injection of Methylene blue dye 1% and the surgical procedure to be performed. The institutional review board approved the trial.

Inclusion Criteria:

Patients 40 to 75 years of age with invasive breast carcinoma and no history of another cancer except skin cancer were eligible for enrollment. Patients who had multicentric cancer or who had previously undergone excisional biopsy were not eligible.

Table No. 1: Patient characteristics

Age (year), mean (range): 48.3 (25-76)

Estrogen receptor positive, progesterone receptor positive, patients (68%), (62%) respectively.

Extensive intraductal component was found in 51 patients (15%).

Table No. 2: Treatment characteristics

The mean number of removed nodes was two (range, 1 to 16), and positive SLN was found in patients. Among the patients with negative SLN, positive conversion in permanent section was shown in two patients. Close or positive resection margin (RM) were found in (06%) patients.

Table No. 3: Clinical Characteristics

Table No. 4: FNR rate according to the number of dissected SLNs

SLN: sentinel lymph node; FNR: false negative rate.

Accuracy and false negative rate of sentinel node biopsy

The accuracy and false negative rate (FNR) according to the number of dissected SLNs. The sentinel node accuracy was 94.9% and the FNR was 5% in all patients with ALND. The FNR of the biopsy decreased as the number of removed lymph nodes increased. Specifically, the FNR was 00% when more than four lymph nodes were removed.

Neoadjuvant chemotherapy (NC) is offered to women with large primary breast tumors in order to shrink the primary tumour prior to definitive locoregional therapy. The optimal timing for SLNB in patients receiving NC has been debated, as some have reported a higher false negative rate for SLNB performed after induction therapy while others have not[7]. The SENTINA trial noted a high false negative rate with SLNB performed after neoadjuvant chemotherapy.

Notable results of this study were that of the 592 women who converted from clinical node-positive to node-negative status, the SLN detection rate was 80 percent. When compared to completion axillary lymph node dissection, the false negative rate for SLNB was 14.2 percent. Notably, the fewer number of nodes harvested in a SLNB, the higher the false negative rate. When one or two nodes were harvested in the SLNB, the false negative rate was approximately 20%[8]. A criticism of this trial to this point is that there is no long-term follow-up with regards to disease free survival, recurrence and mortality data. Similar to the SENTINA study, the ACOSOG Z1071 (Alliance) trial sought to determine the false negative rate (FNR) of SLNB after neoadjuvant chemotherapy for those patients with clinically-positive nodes that converted to clinically-negative node status. Similar to the SENTINA study, the ALLIANCE study confirmed that the FNR seemed to decrease when more than a single SLN was examined; 31.5% with one, 21% with two, and 9.1% with three or more. Again, mortality, disease recurrence and disease free survival have not been reported and will be important in recommendations regarding SLNB timing with regards to neoadjuvant chemotherapy. Lastly, an oncologist has the option of obtaining an axillary ultrasound in the clinically negative axilla to better delineate the need for a SLNB versus an ALND[9-10]. The 2011 NCCN guidelines recommend that SLNB be performed prior to NC because it provides valuable prognostic information for planning locoregional treatment.

Research by Golshan et al., (2006)[11] stated that methylene blue has high sensitivity and specificity in detecting sentinel lymph node metastasis, which is like this research where sensitivity is 91.6% and specificity is 96.6%. Nour (2004) [12] in his research, also stated that methylene blue alone can identify sentinel lymph node metastasis in breast cancer patients.

Brahma et al., in 2017[13] conducted similar research in 96 patients with a sensitivity of 92% and specificity of 100%. PPV and NPV of the research are 100% and 90% respectively. Li et al., (2017) did other research that supported the same idea in 2014 with sensitivity 87%, NPV 91%, and AR 94%. Another research by Ozdemir et al., (2014) [14] in Turkey has a sensitivity of 85% and specificity of 100% also PPV and NPV are 90% and 100% respectively.

The sentinel lymph node biopsy is a safe, reliable and reproducible operation that provides an accurate assessment of nodal metastasis for the breast cancer patient. It continues to add to the trend in breast surgery in which the surgeon provides less surgery while maintaining a standard of care that minimizes breast cancer morbidity and mortality.

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