Clinical Oncology Service
Veterinary Hospital of the University of Pennsylvania
Ultima Vez Modificado: 1 de noviembre del 2001
Tumors of the nasal passages and sinuses account for 1-2% of all cancers in dogs. These tumors tend to grow into surrounding tissues, but have a low chance of spreading (metastasis) to other parts of the body. When they do spread, the most likely sites are the regional lymph nodes and the lungs. If no treatment is done, dogs live an average of 3-5 months after being diagnosed. Chemotherapy alone can offer improvement in a dog's clinical signs, but it does not prolong survival. Similarly, surgery alone does not generally result in prolonged survival. Radiation therapy with or without surgery (depending on the type of radiation used) provides the longest survival attained so far in dogs with nasal tumors. Dogs live an average of 1 to 1 1/2 years with this treatment. However, most dogs eventually die as a result of their tumor. It is important to realize that any individual dog might do much better or much worse than this "average". At VHUP, treatment for nasal tumors consists of a combination of surgery and low energy radiation. Other facilities on the East Coast offer high-energy radiation, which eliminates the need for surgical removal of the tumor. In selected cases, chemotherapy may be recommended as well.
The surgery (rhinotomy) involves removing all the tissues within the nasal passages through an incision over the bridge of the nose. The procedure takes about two hours, and a blood transfusion is sometimes administered during or after the surgery. Your dog will be hospitalized for 2 to 3 days to monitor for excessive bleeding, swelling, or air accumulation around the incision site. After the surgery, there will be a drain placed in the nasal passages for several days. During this time, an "Elizabethan" collar (a large plastic cone) must be worn to prevent your dog from dislodging the drain. There will be nasal discharge, at times bloody, for 1-2 weeks after the surgery. There may also be swelling and puffiness around the face and head during this time.
Radiation therapy is started as soon as the surgical site has healed, which typically takes about 2-3 weeks. Treatment is given in twelve sessions on a Monday-Wednesday-Friday schedule for 4 weeks. Each session requires a brief anesthetic period to insure that your dog does not move during the treatment, which takes about 10 minutes. The entire treatment period (from when you arrive at VHUP to when you leave) takes about 1-2 hours. Your dog should have no food after 8 PM the nights before a radiation treatment, but water should be available throughout the night. No topical medications should be placed on the radiated area the mornings of treatment.
Your dog will develop radiation dermatitis and mucositis, also known as radiation "burns", starting during the third to fourth week of radiation therapy, and lasting for a total of 2-4 weeks. The side effects are limited to the treatment field, and will include the oral cavity and one eye. There will be loss of hair, redness, and oozing. During this time, your dog will again need an Elizabethan collar to prevent scratching or rubbing of the area, and topical medications for the skin and eyes may also be used. Additional medications may include antibiotics and pain medications. Your dog should be encouraged to eat soft, moist foods during the recovery period. When the burns heal, the skin will initially be pink and hairless. The area will become freckled, and after several months hair may start to regrow, which is usually sparse and of a different color. Over months, tear production will slowly decrease, and your dog will need artificial tears. The eye within the treatment field may gradually lose vision over months to years. As a result of changes to the nasal passages caused by both the surgery and radiation, your dog will probably have a mild, persistent mucus nasal discharge. There is a very small risk (less than 5% of cases) of serious complications that could require additional treatment, such as a non-healing skin wound.
Treatment of nasal tumors requires a large commitment of time, energy, and supportive care, as well as finances. This treatment option may not be the most appropriate choice for every dog or every owner. There are many factors besides medical ones that must be taken into consideration, and there is no "right" or "wrong" treatment decision, only what is best for your pet and your family.
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