(LSM P5) Exploring Head and Neck Melanoma Sentinel Lymph Node Outcome Compliance with Multicenter Selective Lymphadenectomy Trials Predicted Outcome

Introduction MSLT established SLN management in extremity/trunk melanoma, demonstrating a 16% +SLN rate and 14% +NSLN in CLND. CLND improved DSS without OS benefit. Results of MSLT guide H&N melanoma but H&N only represented 13% of patients in MSLT II. This project explored validating the observations reported in MSLT II in H&N. Methods Retrospective H&N melanoma population treated 2005-2019. 124 ≥T1b with SLN injection and 108 SLN dissections performed. CLND were functional dissections. Complication rates, T-stage, rates of +SLN, +NSLN in CLND were calculated, as well as death due to disease (DOD), progression free survival (PFS), along with rates of local (LR), nodal (LNR), and systemic (SR) recurrence. Results T-stage was 41% IB, 23% IIA, 28% IIB, 8% IIC. Nerve complication was 4% for SLN and 11% for CLND. –SLN group survival is 93% compare to survival of 70% for +SLN group with median follow-up of 40 months. Rate of +SLN was 29% (24% IB, 30%-IIA, 33%-IIB, 33%-IIC) and +NSLN rate for CLND was 50%. +SLN, no CLND LR 0%, LNR 9%, SR 27% and 18% DOD compared to LR 35%, LNR 60%, SR 55% and 40% DOD in the CLND group with lower LR (p=0.03) and LR/LNR (0.02).

Conclusion: +SLN rate was 2-fold higher and +NSLN following CLND was 3-fold higher in H&N melanoma. Local regional recurrence rates were higher for CLND compared to SLNB+ only. These results support nodal behavior and failure patterns in H&N may be different from trunk/extremity, supporting consideration of dedicated H&N trial.