Treatment of Metastatic Squamous Cell Carcinoma (or Advanced Disease Untreatable by Local Modalities)

As is the case with basal cell carcinoma (BCC), metastatic and far-advanced SCC is unusual, and reports of systemic therapy are limited to case reports, small case series, or early-phase trials with tumor response as the end point.[Level of evidence C3] The metastatic rates are 5% for primary tumors of sun-exposed skin, 9% for tumors of the external ear, and 14% for tumors of the lip. Metastases occur at an even higher rate (about 38%) for primary SCCs in scar carcinomas or in nonexposed areas of skin.[9] About 69% of metastases are diagnosed within 1 year, 91% within 3 years, and 96% within 5 years.