The prognosis for dogs with oral melanoma can vary depending on various factors, such as the cancer stage, the tumor's location and size, and metastasis (spread to other body parts). Oral melanoma is considered an aggressive form of cancer in dogs, and the prognosis is generally guarded. Without treatment, the survival time for dogs with oral melanoma is often around 1-5 months. However, the survival time can be extended with appropriate treatment, including surgery, radiation therapy, and immunotherapy. Some dogs may live for several months to a year or more with treatment. Unfortunately, 90% of malignant melanomas have already spread at diagnosis. Therefore, it's essential to consult with a veterinarian or veterinary oncologist who can provide a more accurate prognosis based on the specific details of your dog's case.