Validation of nomograms to predict non-sentinel lymph node metastasis after positive sentinel lymph node in breast cancer: Indian cohort background.

568 Background: Axillary lymph node metastasis is still the important prognostic factor in the management of breast cancer (BC). Where we have moved towards axillary conservation in clinically node negative (cN0), the debate on what after 1-2 sentinel lymph nodes positive (SLN+ve) still continues. The ideal situation would be wherein we can accurately predict which patient has a risk of additional non SLN+ve. Several nomograms have been developed to predict the risk of NonSLN+ve. But in view of the differences in tumor size and nodal burden between our patients and the western data, we conducted a study to validate some of these nomograms in our cohort of early BC with positive LN on Low axillary sampling (LAS). Methods: Clinico-pathological data was collected for operable BC (OBC) with cN0 who underwent upfront SLNB or AS. This was entered into the various nomograms and the probability of the Non SLN+ve was calculated. Nomograms with AUC of greater than 0.7 were pre-defined as considerable discrimination. Results: From 2013 to 2018, 2350 women with cN0 OBC underwent LAS. Of which, 670 (28.5%) had a positive node on LAS. Median pT size was 3 cm with 327 (48%), LVI +ve 152 (77%) ENI +ve, 525 (78.4%) Hormone receptor +ve and 485 (72.4%) grade 3 tumors. Of 670, 239 (35.7%) had a NonSLN+ve on completion axillary dissection. The AUC values for nomograms included,ie. MSKCC, MDAnderson, Tenon, Cambridge, Shanghai, Mayo clinic and Turkish were 0.769, 0.77, 0.55, 0.74, 0.65, 0.529, 0.563 respectively. Only three nomograms, MDA, MSKCC and Cambridge had an AUC of more than 0.7. However, they were associated with poor sensitivity and specificity and high FNR (Table) making them clinically unreliable for this cohort. Conclusions: All 7 nomograms were not validated in our study. The larger T size and higher nodal burden of our cohort may be responsible for the same. We thus need to develop an Indian nomogram to predict the risk of non SLN+ve for our patients. [Table: see text]

Randomized surgical multicenter trial to evaluate the usefulness of lymphoscintigraphy (LSG) prior to sentinel node biopsy (SLNB) in early breast cancer: SenSzi (GBG80) trial.

555 Background: It is not clear whether SLNB performed with LSG is necessary to reliably detect sentinel lymph nodes (SLN) in breast cancer. The omission of LSG might offer an accelerated preoperative workflow, cost reduction, and the opportunity for developing innovative, safe detection strategies. Methods: Patients with cN0 early breast cancer or extensive/high grade DCIS received standard radiolabeled colloid LSG and SLNB. Patients were randomized 1:1 to either conducting SLNB with the performing surgeon knowing the preoperative LSG pictures and results or without knowledge of the LSG results. Since the false negative rate (FNR) of SLNB correlates with the number of harvested SLN, our primary endpoint was the average number of histologically detected SLN per patient in both treatment arms in a non-inferiority design. An average number of 2.7 SLN with a standard deviation of 1.8 was assumed. LSG of all patients were collected postoperatively for central review. Results: Between May 2014 and October 2015 n = 1198 patients were randomized in 23 participating breast centers. Baseline characteristics were well-balanced between the treatment arms. Modified intention-to-treat analysis (n = 1163) confirmed the omission of LSG. The average number of histologically detected SLN was 2.207 with LSG and 2.258 without. The range for the one-sided 95% CI for the difference between the arms was (-0.18, +infinity), i.e. above the pre-specified non-inferiority margin of -0.27. Secondary endpoints were analyzed to rule out differences in reliable detection of nodal metastases. Rates of nodal positive disease as identified by SLNB (Odds ratio (OR) 1.005, 95%CI (0.759, 1.33), p = 0.972) and rates of completion axillary dissection (OR 0.984, 95% CI (0.567, 1.71), p = 0.954) in the two treatment arms and in specific subgroups showed no statistically significant differences. Conclusions: Our results support the hypothesis that SLNB is equally effective irrespective of the knowledge of preoperative LSG results. We therefore suggest performing SLNB without LSG to accelerate the preoperative workflow, reduce costs, and improve the comfort for the patients. Clinical trial information: NCT02481128.

The Predictive Value of Micrometastasis in Nonsentinel Lymph Nodes

The rate of micrometastatic disease (MMD) to nonsentinel lymph nodes (NSLNs) has been shown to vary considerably in the literature. We identified patients with breast cancer with MMD (N1mi) and measured the incidence of NSLN involvement. We then compared these patients with those who had no metastasis to the SLN (N0) and those who had macrometastasis to the SLN (N2) in an attempt to better understand the behavior of patients with N1mi positivity. A retrospective analysis was conducted on 574 patients with invasive breast cancer between January 2000 and December 2007. Patients were stratified into three groups: no metastasis (N0), MMD (N1mi), and macrometastasis (N2). Chi square analysis and logistic regression models using SPSS software were applied to determine significance between groups. MMD rate was 7.7 per cent (44 of 574). Of this subset of patients, 33 underwent completion axillary dissection, and only two were found to have NSLN-positive disease. Statistical significance was achieved for NSLN positivity when comparing all three nodal groups against one another (χ22,572 = 337.084, P = 0.000). Logistic regression showed multifocality and lymphovascular invasion to be significant predictors of NSLN metastasis. NSLN positivity in patients with MMD acts similarly to node-positive disease and therefore cannot completely exclude axillary dissection from therapeutic algorithm.