Clinical Features and Outcomes of Locally Advanced and Metastatic Basal Cell Carcinoma

Cutaneous basal cell carcinoma (BCC) is a primarily indolent tumour that is easily cured. However, locally advanced BCC (laBCC) and metastatic BCC can have a poor prognosis. This retrospective cohort study, conducted at a single cancer centre over a 32-year period, reports the characteristics and clinical course of 51 patients with laBCC or metastatic BCC. Thirty-five patients were men (69%), with a mean age of 72 years. Most primary BCCs were located in the head and neck (59%), and were treated with surgery (78%). Thirty-four patients had laBCC; 6 of those developed subsequent metastasis. Twenty-three metastatic BCCs were included. The median size of laBCC was 73 mm (IQR 110; range 15-400 mm), with 71% measuring 5 cm or larger. Tumour infiltration beyond the subcutaneous fat was present in 59% of laBCC and bone infiltration in 12%. Of laBCC, 44% experienced local recurrence after resection, which was seen in 35% of local tumours later developing metastasis. Median time to metastasis was 33 months. Most patients developed nodal metastases only (70%), but 26% developed distant metastases. Fifteen patients died during follow-up (29%). Three patients died of their laBCC with a 5-year disease-specific survival of 79%. Five-year disease-specific survival for metastatic BCC was 30%. Patients with laBCC in this cohort were at high risk of local recurrence and metastasis, and 12% died of their laBCC. These findings highlight the need for intensified follow-up for this relatively rare population, especially since Hedgehog inhibitors and PD1 inhibitors might be available for these patients.