Meningioma by John R. Mangiardi, M.D. and Howard Kane, Wm.

Life after surgery.
The downside is that no matter how thorough your surgeon may be, there will probably be some tumor cells that remain after the main mass is removed.
      Because meningioma is benign, these cells won't spread to other parts of the body. However, they probably will continue to multiply.  Each case is different in how fast, or how slowly this will occur. Some even say that the tumor cells may grow faster after the operation.
      Eventually, the new tumor cells may fill the space that the old tumor left behind.  At that point, pressure in the dog's brain begins to build.  This pressure will begin to cause old symptoms to reappear, or for new ones to develop. Seizures may start up again, or increase in severity.
      Your veterinarian will probably prescribe a steroid like prednosolone to shrink the tumor cells, and to prolong the time before the tumor outgrows the available space.

Radiation is a possibility for some dogs. This treatment can help clear out the remaining tumor cells and prevent them from growing back. Even though radiation is not without the possibility of potentially serious side effects, the course prescribed for animal patients is not as rigorous as that used for humans. A less intense, gentler approach is favored instead of the all out assault that is used to treat humans.
      Even so, radiation may not be advisable for older dogs, or dogs with other serious health problems. If radiation therapy is a possibility for your dog, your veterinarian will help you weigh the possible advantages against the possible risks.
      Unfortunately, chemotherapy has not yet been found effective in treating tumors of the brain in dogs.

More time to live.
On the plus side, by surgically removing the tumor, your dog will probably gain a good extension of his or her lifespan. The usual scenario is in the range of about a year. Most dogs recover relatively quickly from surgery and experience a lessening of pain and debility.
      Many dogs that develop meningiomas are in their senior years, and there is a chance that they may succumb from some unrelated problem — for example, an unrelated cancer, heart disease or kidney failure — before the tumor grows back.
      The good part is, if your dog remains otherwise healthy, these additional months could be relatively happy ones.
      Because the cause of increased pressure on the brain is removed, your dog may experience some relief from pain, as well as the number and severity of seizures.  If all goes well, your dog's neurologist may decide to try backing him down on his seizure controlling medications.

What if we decide against surgery?
There are many reasons why you may decide against choosing surgery for your dog. Your budget may not allow it. Or, your dog may have health problems that make surgery too risky. If your dog is very old, it is possible that surgery will not greatly extend his or her life. Because of factors such as the size or location of the tumor, surgery sometimes is not possible.
      In JoJo's case, the tumor was found to be operable, but for many reasons, most important of which was his overall poor health, we decided against surgery. It was an extremely difficult decision, and we second-guessed ourselves daily.
      After JoJo died, reports from the autopsy showed that in addition to the brain tumor and heart problems, he also had the beginning of a lung cancer (a primary adenocarcenoma). Based on this, we found he probably would not have survived much longer, even with heroic measures. In the end, we are as comfortable with our decision as is possible in such a situation.
      Each case is different, however, and some are much more hopeful than JoJo's. You may decide your best course is to opt for surgery and an extension of life. In this case, I wish you success and I invite you to write to me to share your experience and outcome. Whatever you decide, my heart goes out to all of you who must now make this difficult decision.