Sentinel node biopsy for high-risk cutaneous squamous cell carcinoma

The use of sentinel node biopsy (SNB) has not been established for cutaneous squamous cell carcinoma (SCC), and its clinical significance has not been clarified. We investigated the usefulness of and indication criteria for SNB for cutaneous SCC.

Twenty-six patients with high-risk cutaneous SCC that had undergone SNB were retrospectively reviewed. SNB was performed with either the dye method or a combined dye and radioisotope method.

Of the 26 patients, recurrence or metastasis was observed in 5 cases (19.2%). Six cases (23.1%) were sentinel node (SN) metastasis-positive. All cases that were SN metastasis-negative survived, and 4 of 6 SN metastasis-positive (66.7%) cases died of the original disease. The 3-year survival rates of all cases, SN metastasis-negative cases, and SN metastasis-positive cases were 82.2%, 100%, and 20.8%, respectively. Tumour thickness was a significant risk factor for SN metastasis (p = 0.049). Recurrence occurred in 4 of 7 cases involving external genitalia, 3 of which died. The 3-year survival rates of external genitalia and nongenital cases were 47.6% and 94.1%, respectively (p = 0.016).

SNB aided the early discovery and treatment of latent lymph node metastasis and helped predict whether SN metastasis had occurred, and therefore helped predict patient prognosis. These results suggest that thickness of the primary lesion is an indication criterion for the use of SNB in cases of cutaneous SCC. SNB should be considered in cases where tumour thickness is ≥2 mm and actively performed in cases ≥5 mm.