Sentinel Lymph Node Identification in Cutaneous Head & Neck Cancer - Lymphoscintigraphy Late Phase

Objective: Sentinel node (SN) biopsy following lymphoscintography is recommended for high-risk cutaneous malignancies. Herein, we investigate different lymphoscintography phases, focusing on the importance of the late static phase and the resultant discovery of distal echelon solitary positive sentinel nodes that would otherwise have been overlooked. Methods: In this retrospective cohort study, conducted in a tertiary referral medical center, we assessed SN localization and time from tracer injection to SN identification on lymphoscintigraphy. Findings on scan were compared with SN found in the surgical field, and with the final pathological investigation. Results: Seventy-three patients, undergoing SN biopsy for head and neck skin malignancies, were investigated. Most patients were male (n = 50). The average age was 65.7 (±15.7) years and the average follow-up time was 29.1 (±22.4) months. Overall, 101 SNs were histologically investigated, demonstrating 7 positive SN. Eleven patients (15%) benefited from the late lymphoscintigraphy phase. In four studies, an SN was identified only in the late static phase, one of which was positive for the disease. In seven patients, SN was identified in the early phase with additional, different, SN on the late phase, one of which was positive for the disease. Comparing the yield (positive SNs) of early versus late phases, demonstrated the same importance (p = 0.275). Conclusions: The late lymphoscintigraphy phase has a crucial role in high-risk HN cutaneous cancer. Level of Evidence: 3 Laryngoscope, 132:2164–2168, 2022.