Comparison of diagnostic characteristics between sentinel lymph node biopsy (SLNB) and radio-guide elective neck dissection (RGEND) in patients with T1-2N0 oral tongue cancer.

Abstract

e18037 Background: Elective neck dissection remains the standard treatment for cN0 oral cancer due to the high incidence of occult lymph node (LN) metastases. Sentinel lymph node biopsy (SNB) might be a less morbid alternative to neck dissection. Diagnostic value of SLNB depends on the number of sampled LNs. We aimed to compare the diagnostic features of SNB and RGEND in patients with T1-2N0 oral tongue cancer. Methods: A prospective study was conducted in patients with cT1-2N0M0 oral tongue squamous cell carcinoma treated between January 2016 and December 2020. The procedure included SLNB ollowed by immediate extent ipsilateral neck dissection. SLNB included accumulated radiotracer LNs, which located close to the primary tumor. RGEND included LNs accumulated radiotracer with all LNs located at the same level. Pathology assessment was performed and diagnostic characteristics were compared between SLNB and RGEND. Results: A total of 38 patients were enrolled. The mean age was 55.7±13,1. Twenty-four patients had unilateral lymph flow and 14 had bilateral. Sentinel LNs were located at levels IIa-III. Occult metastases were found in 15,8% (n = 6) of patients. The median number of LNs in the sample was 3 (IQR: 1-5). The sensitivities of SLNB and RGEND were 50% (95%CI: 15.7 - 84.3) and 100% (95%CI: 54.7-100), respectively, p-value = 0.001. Specificity was similar among groups: 100% (95%CI: 88-100) and 100% (95%CI: 89.1-100. SLNB had accuracy of 89.5% (95%CI: 77.2 - 97), and RGEND 100% (95% CI: 90.7-100), p-value = 0.001. Positive predictive value (PPV) was similar among groups. Negative predictive value (NPV) was 88.2% (95% CI: 78.9 - 93.7) in SLNB and 100% (95%CI: 91-100) in RGEND groups. p-value = 0.001. Conclusions: SLNB and RGEND have high rates of specificity, accuracy, PPV, and NPV, regardless of sampling size. RGEND has the highest sensitivity in patients with cT1-2N0 oral tongue cancer.