Introduction

Canine oral melanoma remains the most common malignant oral tumor; the primary treatments are wide-margin surgery and radiation therapy (RT). In human melanoma, several immunotherapies were approved, and recent studies also focus on the combination of immunotherapy and RT. Less is known about the combination treatment; thus, this research hypothesizes that combining immunotherapy and RT will provide clinical benefit.

Methods

The immunotherapy used is the dendritic cell/tumor cell fusion vaccine. Dendritic cells are separated and cultured from healthy dog’s blood, then fused with tumor cells from canine patients. Hypofractionated RT was utilized, with 7.5–8.5 Gy, weekly in 5 fractions, and regional lymph node included. Vaccination will start after the 2nd radiation treatment. A total of four doses was administered two weeks intervals. Response and adverse effects will be recorded and monitored by physical and hematological examination.

Results

Five dogs were recruited. All had CR or PR after RT, 1 had lung metastasis four weeks after last RT. 2 had local recurrence 79 days, and 219 days after initial RT. 4 patients died, and one is still alive. Three died of tumor-related reasons at 125, 152, and 293 days after diagnosis. One had sudden death without local or distant progression at 83 days after diagnosis. The alive one patient is progression-free now, follow-up 674 days.

Conclusion

Though the case number is low, the effect of combination therapy still warrants further investigation. Detailed cytokine changes and cell analysis will provide us more information.

Funding Information

The study has no funding.