Prediction of Sentinel Lymph Node Biopsy Status in Breast Cancers with PET/CT Negative Axilla

Background and Aim Prior knowledge of axillary node status can spare a lot of patients with early breast cancer morbidity due to an unnecessary axillary dissection. Our study compared various metabolic and pathological features that can predict the sentinel lymph node biopsy (SLNB) status in patients with positron emission tomography/computed tomography (PET/CT) negative axilla. Patients and Methods All consecutive patients with early breast cancers (< 5 cm) with PET/CT negative axilla who underwent breast surgery and SLNB from November 2016 to February 2020 were included. Various primary tumor (PT) pathological variables and metabolic variables on PET/CT such as maximum standardized uptake value (PT-SUV (max) ), metabolic tumor volume (PT-MTV), and total lesion glycolysis (PT-TLG) were compared using univariate and multivariate analyses for prediction of SLNB status. Results Overall 70 patients, all female, with mean age 55.6 years (range: 33–77) and mean tumor size 2.2 cm (range: 0.7–4.5), were included. SLNB was positive in 20% of patients ( n = 14) with nonsentinel nodes positive in 4% ( n = 3) patients. Comparing SLNB positive and negative groups, univariate analysis showed significant association of SLNB with low tumor grade, positive lymphovascular invasion (LVI), positive estrogen receptor (ER) status with lower mean K (i) -67 index (34.41 vs. 52.02%; p = 0.02), PT-SUV (max) (5.40 vs. 8.68; p = 0.036), PT-MTV (4.71 cc vs. 7.46 cc; p = 0.05), and PT-TLG (15.12 g/mL.cc vs. 37.10 g/mL.cc; p = 0.006). On multivariate analysis, only LVI status was a significant independent predictor of SLNB status (odds ratio = 6.23; 95% confidence interval: 1.15–33.6; p = 0.033). Conclusion SLNB is positive in approximately 20% of early breast cancers with PET/CT negative axilla and SLNB status appears to be independent of PT size. SLNB+ PTs were more likely to be LVI+ and ER + ve, with lower grade/K (i) -67/metabolic activity (SUV (max) /MTV/TLG) compared with SLNB–ve tumors. Logistic regression analysis revealed LVI status as the only significant independent predictor of sentinel lymph node status.