If treatment is financially possible for you, I do think it very important to have the biopsy. That's the only way to know what is possible. I recommend that you consult a veterinary oncologist at this time. An oncologist can stage the cancer and assess all factors to determine the best steps. This link will take you to a directory of oncologists:
If your state has a veterinary teaching hospital, there would certainly be an oncologist on staff there, as well.
There are two types of tumors that occur on the heart. One is hemangiosarcoma. This cancer often starts elsewhere in the body, and by the time it has spread to the heart, the prognosis is not good. The other type is called an aortic body tumor. This type can be benign or malignant. . A surgical technique called palliative pericardectomy can be performed. It is removal of as much of the tumor as possible. Before knowing if any procedure would help, the type of tumor your dog has would have to be determined. Because your dog's heart was shaped like a tennis ball, and fluid had to be drained, it seems most likely that this is hemagiosarcoma. You can read more about this cancer on the heart here:
Tumors on the spleen are also often hemangiosarcoma. Most vets recommend surgical removal, even if no other treatment is being done. The surgery alone doesn't result in longer life. What it does is stop the risk of sudden death from rupture, and it alleviates some symptoms. About 10% of dogs are still alive after one year, when surgery is the sole treatment. A few weeks to a few months is typical.
Chemotherapy doesn't cure this type of cancer, but it does lead to a longer life, and good quality for much of the increased time. With chemo, the mean survival time increases to about 400 days. The following links have details on studies, treatment methods, and staging. The early stages of the disease are generally those that have the best prognosis.
If you'll read the sites, you'll also see that there have been some studies done with an additional therapy similar to the cancer vaccines that have been studied in humans. Survival times with that therapy, in conjunction with chemo, increased even more.
With cancer, there are so many factors to consider before deciding on treatment. It can be expensive, so for many people finances are a consideration. Another is the importance of getting an oncologist's opinion. Many local vets simply recommend pain relief because they aren't aware of the latest treatments. An oncologist is up-to-date on them, and is in the best position to assess each individual case to decide what to do. There are, of course, cases that are so advanced that treatment isn't an option. Conversely, some cases that seem hopeless at the outset actually respond well to treatment. The only way to know is to see an oncologist.
There is a lot of misinformation about canine cancer online. The sites I've given you are reputable. I suggest you read the, and if you have follow-up questions afterward, come back here. Just click on REPLY - there is no additional fee. Whatever you decide to do, I hope for the best possible outcome for your dog.
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