Can dogs get cancer; unfortunately, the answer to this question is yes. The worst thing about cancer in dogs is that a dog can withstand much more pain than a human can, so by the time you realize there is something wrong, the cancer could be in advanced stages.
The most common cancers that are seen in dogs are breast cancer, bone cancer, skin cancer, mouth cancer, and cancer of the lymphatic system. Breast cancer is most common in female dogs, but it can show up in males also. It usually appears in older dogs, especially those that were not spayed, or spayed after they became adults. If your dog has breast cancer you will be able to feel firm lumps or masses near the nipples. Typical treatment for breast cancer is to remove the lump and then start chemotherapy. Treatments are expensive and usually not successful because by the time it is diagnosed the cancer will have spread throughout the dog.
Bone cancer is usually seen in the legs of older large breed dogs. Treatment calls for the removal of the affected leg and chemotherapy. Like breast cancer, treatment is considered a success if the dog lives a year past diagnosis. Skin cancer will appear as lumps or nodules on the body of the dog. If skin cancer is found early, radiation and chemotherapy can extend the life of the dog for several years. The symptoms of mouth cancer are bad breath, blood in the saliva, and difficulty eating. Like most cancers in dogs, by the time this cancer is found it is in advanced stages and treatment is not usually effective.
There are four main causes that lead to cancer in dogs. The first is genetics, some breeds carry cancer genes. Various types of infections can turn to cancer; papilloma virus often turns to mouth cancer. Hormones can cause cancers in dogs, especially breast cancer. That is why you should have a female spayed as a puppy unless you intend to breed the dog. The environment your dog is exposed to can cause cancer, especially if the dog is exposed to cigarette smoke. There is also recent evidence that shows that modern types of topical flea and tick treatments can cause cancers in dogs.