Background: Sentinel lymph node biopsy (SLNB) has been introduced as a diagnostic staging modality for detection of occult metastases in patients with early stage oral cancer. Comparisons regarding accuracy to the routinely used elective neck dissection (END) are lacking in literature. Methods: A retrospective, multicenter cohort study included 390 patients staged by END and 488 by SLNB. Results: The overall sensitivity (84% vs. 81%, p = 0.612) and negative predictive value (NPV) (93%, p = 1.000) were comparable between END and SLNB patients. The END cohort contained more pT2 tumours (51%) compared to the SLNB cohort (23%) (p < 0.001). No differences were found for sensitivity and NPV between SLNB and END divided by pT stage. In floor-of-mouth (FOM) tumours, SLNB had a lower sensitivity (63% vs. 92%, p = 0.006) and NPV (90% vs. 97%, p = 0.057) compared to END. Higher disease-specific survival (DSS) rates were found for pT1 SLNB patients compared to pT1 END patients (96% vs. 90%, p = 0.048). Conclusion: In the absence of randomized clinical trials, this study provides the highest available evidence that, in oral cancer, SLNB is as accurate as END in detecting occult lymph node metastases, except for floor-of-mouth tumours.

SNB is a reliable diagnostic staging technique for the clinically negative neck in patients with early-stage (T1-T2, cN0) oral squamous cell carcinoma.

Purpose Sentinel lymph node (SLN) biopsy has proven to reliably stage the clinically negative neck in early-stage oral squamous cell carcinoma (OSCC). [99mTc]Tc-tilmanocept may be of benefit in OSCC with complex lymphatic drainage patterns and close spatial relation to SLNs. Methods A prospective within-patient evaluation study was designed to compare [99mTc]Tc-tilmanocept with [99mTc]Tc-nanocolloid for SLN detection. A total of 20 patients with early-stage OSCC were included, who underwent lymphoscintigraphy with both tracers. Both lymphoscintigraphic images of each patient were evaluated for SLN detection and radiotracer distribution at 2–4 h post-injection. Results The injection site’s remaining radioactivity was significantly lower for [99mTc]Tc-tilmanocept (29.9%), compared with [99mTc]Tc-nanocolloid (60.9%; p < 0.001). Radioactive uptake in SLNs was significantly lower for [99mTc]Tc-tilmanocept (1.95%) compared with [99mTc]Tc-nanocolloid (3.16%; p = 0.010). No significant difference was seen in SLN to injection site ratio in radioactivity between [99mTc]Tc-tilmanocept (0.066) and [99mTc]Tc-nanocolloid (0.054; p = 0.232). A median of 3.0 and 2.5 SLNs were identified with [99mTc]Tc-tilmanocept and [99mTc]Tc-nanocolloid, respectively (p = 0.297). Radioactive uptake in higher echelon nodes was not significantly different between [99mTc]Tc-tilmanocept (0.57%) and [99mTc]Tc-nanocolloid (0.86%) (p = 0.052). A median of 2.0 and 2.5 higher echelon nodes was identified with [99mTc]Tc-tilmanocept and [99mTc]Tc-nanocolloid, respectively (p = 0.083). Conclusion [99mTc]Tc-tilmanocept had a higher injection site clearance, but at the same time a lower uptake in the SLN, resulting in an SLN to injection site ratio, which was not significantly different from [99mTc]Tc-nanocolloid. The relatively low-radioactive uptake in SLNs of [99mTc]Tc-tilmanocept may limit intraoperative detection of SLNs, but can be overcome by a higher injection dose.