(0748) To Drain or Not to Drain: Sentinel Lymph Biopsy for Head and Neck Melanoma

Introduction: Sentinel lymph node biopsy (SLNB) is a vital staging tool for cutaneous melanoma, allowing detection of regional metastasis. In the head and neck (H&N) region, the success of radiotracer drainage and subsequent biopsy in SLNB is distinctly complicated by factors including complex lymphatic drainage patterns and proximity of critical anatomy.

Methods: In this retrospective cohort study, patients with Stage I and II cutaneous malignant melanoma of the H&N undergoing Mohs micrographic surgery (MMS) and SLNB between October 2006 and January 2023 at a tertiary academic medical center were included. The primary outcome was successful radiotracer drainage, defined as drainage sufficient to mark lymph node(s) for excision. Secondary outcomes included successful biopsy, defined as excision of at least one lymph node; and complications of SLNB. Statistical analyses were performed in RStudio.

Results: 285 patients were included. Of these, 249 (87%) had successful radiotracer drainage and 241 (85%) had successful biopsy. Successful drainage was significantly associated with age < 65 years (p-value=0.001) and SLNB before (vs. after) MMS (p-value=0.003); drainage success was not significantly associated with gender, immunosuppression, lymphovascular invasion, T-stage, MMS margin status, incomplete surgical excision preceding SLNB, or biopsy to SLNB interval. Biopsy success was significantly associated with age < 65 years (p-value < 0.001), SLNB before MMS (p-value=0.005), successful drainage (p-value < 0.001), and lack of cross-sectional imaging (p-value=0.042). SLNB complications were observed in 8 patients (3.8%), including wound infection or dehiscence, seroma, hematoma, sialocele, and temporary facial nerve temporal branch paresis.

Conclusions: Success of radiotracer drainage in SLNB of H&N melanoma may be improved by performing SLNB prior to MMS and predicts successful biopsy. Of interest, time elapsed to SLNB and radiotracer injection into scar (vs. melanoma) are not significantly associated with successful drainage. SLNB in the H&N region is generally safe with low complication rate.