This is a continuation of the previous blog topic, radiation therapy in dog cancer.
We looked at some benefits of radiation previously, both in terms of life quality and lifespan.
This time, I would like to look at some of the downsides. I am not interested in painting a darker picture than is necessary. This is a treatment where a rationale approach in needed, where good and bad are evaluated. As an owner and guardian of your dog, you should be advised of things so you can make educated decisions.
Radiation therapy is no joke. Each treatment requires general anesthesia, and protocols for designed for cancer remissions involve multiple treatments each week, sometimes even daily. Multiple rounds of general anesthesia should be taken into account when making a decision about radiation, especially in senior dogs. Most vets would agree that an aged canine and 30 rounds of general anesthesia may not be a good mix.
Palliative treatment, radiation designed for the comfort (pain control) of the dog, is less frequent, perhaps weekly for a month or so. This seems a bit “easier on the system” overall.
The radiation in the beam, if it contacts other living tissue, will damage it as well. Sometimes there is radiation scatter, which is where the beam directed at the tumor actually ends up hitting a bit of normal (non cancerous) body tissue.
There can be some side effects that may be seen immediately following treatment, when the beam contacts normal body parts.
The skin can get a little inflamed, similar to a sunburn. There may be nausea, vomiting, diarrhea, and loss of appetite. If radiation contacts the mouth, irritation and sores may occur within mucus membranes lining the mouth. This can be painful and require care. If the beam or scatter contacts the gland that makes tears to lubricate the eye, injury can occur to the glands. This requires lifetime lubricating ointment to be put in the eyes. Similarly, the lining of the lungs can become damaged if they are exposed to radiation.
All of these effects can occur within days or weeks of radiation treatment and examples of acute toxicity.
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Radiation consequences can occur years later…delayed radiation toxicity. This can include injury to kidneys, nerves or spinal cord, and ligament damage.
A bizarre delayed toxicity form is the development of new cancers, as a consequence of the radiation. This is documented with cases of osteosarcoma (bone cancer), bladder tumors, and connective tissue tumors.
Take home message? Radiation is not a minor therapy. Consider it carefully. Be advised if you have a young dog that you are considering radiation for, you may see delayed toxicity, years later but during the dog’s lifespan, even in the form of new cancers.
Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.