Combined systemic and intratumoral administration of human papillomavirus vaccine to treat multiple cutaneous basaloid squamous cell carcinomas

IMPORTANCE Squamous cell carcinoma (SCC) is the second most common form of skin cancer, and its incidence is increasing. When surgical management is not an option, finding a safe and efficacious treatment is a challenge. Mounting evidence suggests that the human papillomavirus (HPV) is involved in the pathogenesis of some SCCs. OBJECTIVE To assess whether the 9-valent HPV vaccine could be an effective treatment strategy for cutaneous SCC. DESIGN, SETTING, AND PARTICIPANTS A woman in her 90s with multiple, inoperable cutaneous basaloid SCCs was successfully treated at a university-based outpatient dermatology clinic with a combination of systemic and intratumoral delivery of the 9-valent HPV vaccine from March 17, 2016, through February 27, 2017, and then followed up through May 21, 2018. MAIN OUTCOMES AND MEASURES Reduction in tumor size and number after a combination of systemic and intratumoral administration of the HPV vaccine. RESULTS All tumors resolved 11 months after the first intratumoral injection of the vaccine. The patient remained free of tumors at the end of follow-up. CONCLUSIONS AND RELEVANCE This is the first report, to our knowledge, of complete regression of a cutaneous malignant tumor after combined systemic and direct intratumoral injection of the 9-valent HPV vaccine. This report suggests that the HPV vaccine may have therapeutic utility for SCCs in patients who are poor surgical candidates, have multiple lesions, or defer surgery.