Utility of sentinel lymph node biopsy for solitary dermal melanomas.

ABSTRACT

BACKGROUND AND OBJECTIVES: Solitary dermal melanoma (SDM) is melanoma confined to subcutaneous and/or dermal layers in the absence of a known primary cutaneous lesion. We hypothesized that sentinel node biopsy is an effective staging strategy for this rare disease. METHODS: A Markov decision model was constructed to represent two management strategies for SDM wide local excision followed by observation, and wide local excision followed by sentinel node biopsy. Utilities, likelihood of positive sentinel node biopsy, and cancer progression rates during a five year time horizon were assigned based on institutional data and a review of existing literature. Estimated costs were derived using Medicare reimbursements. RESULTS: Excision followed by sentinel node biopsy provides greater utility, yielding 3.85 discounted quality-adjusted life years (dQALY) compared to 3.66 for excision alone. The incremental cost-effectiveness ratio for sentinel node biopsy is $19,102 per dQALY. Sensitivity analyzes demonstrated that observation is more cost-effective if greater than 23% of sentinel node biopsies are positive (16% reported), or if 5-year survival for observed patients is greater than 76% (69% reported). CONCLUSIONS: Based on existing clinical evidence, sentinel node biopsy yields greater utility than excision alone and is cost-effective for patients presenting with solitary dermal melanoma.