Disclosed is a method for treating canine mammary carcinoma/tumor in a dog suffering from a canine mammary carcinoma/tumor comprising: a) surgically debulking the tumor； and b) administering to the dog a clinically-effective amount of a xenogeneic differentiation antigen of the same type as a differentiation antigen expressed by mammary cells of the dog； and wherein canines receiving the antigen exhibit significantly increased overall, disease-free, and/or metastasis-free survival times relative to canines receiving the surgical debulking without subsequent immunization, thereby treating the carcinoma/tumor.
