Immune checkpoint inhibitors for children with xeroderma pigmentosum and advanced cutaneous squamous cell carcinoma: A case presentation and brief review.

Patients with xeroderma pigmentosum (XP) frequently develop skin cancers early in life, including cutaneous squamous cell carcinoma (cSCC). The median age of death is 32 years and 60% of XP patients die before the age of 20 years. cSCC in patients with XP exhibits an exceptionally high mutation burden, suggesting a favorable response to immune checkpoint inhibitors (ICIs). We present the case of a 7-year-old boy with XP and a large facial cSCC complicated by cervical lymph node metastases. Following a tumor board recommendation, systemic immunotherapy with cemiplimab was initiated. Following therapy, the tumors rapidly and completely regressed. To date, only 10 XP patients worldwide have been reported to receive ICIs for inoperable and/or advanced cSCC, with all cases demonstrating tumor regression under ICI treatment. Among these, three were pediatric cases with XP-C (one 7-year-old and two 6-year-old children), one of whom had sarcomatoid cSCC. Incidence and nature of adverse events in XP patients were comparable to those observed in the general population. In line with the previously reported ICI-treated XP children, the present case confirms that anti-PD-1 inhibitors are highly effective in children with XP and advanced cSCC.