Sentinel lymph node biopsy for high-risk cutaneous squamous cell carcinoma: clinical experience and review of literature

High-risk cutaneous squamous cell carcinoma (SCC) is associated with an increased risk of metastases. The role of sentinel lymph node (SLN) biopsy in these patients remains unclear. To address this uncertainty, we collected clinical data on six patients with clinical N0 high-risk SCC that underwent SLN biopsy between 1999 and 2006 and performed a literature review of SLN procedures for SCC to study the utility of SLN biopsy. There were no positive SLN identified among six cases and there was one local and one distant recurrence on follow-up. Literature review identified 130 reported cases of SLN biopsy for SCC. The SLN positivity rate was 14.1%, 10.1%, and 18.6%; false negative rate was 15.4%, 0%, and 22.2%; and the negative predictive value was 97.8%, 100%, and 95.2% for all sites, head/neck, and truncal/extremity sites, respectively. SLN biopsy remains an investigational staging tool in clinically node-negative high-risk SCC patients. The higher false negative rate and lower negative predictive value among SCC of the trunk/extremity compared to SCC of the head/neck sites suggests a more cautious approach when treating patients with the former. Given the paucity of long-term follow up, an emphasis is placed upon the need for close surveillance regardless of SLN status.