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.