Nowadays, there are three main ways of treating cancer in both pets and humans: surgery, chemotherapy, and radiotherapy.
In today’s article, we’re looking at what radiation therapy is, what types there are, what kinds of cancer it can treat and is appropriate for, and what side effects can be expected from this type of treatment.
What Does Radiation Therapy Mean?
As its name suggests, radiotherapy involves the administration of a particular type of radiation with the aim of killing the cancer cells in the specific body area where they developed.
The most common type of radiotherapy involves the use of x-rays, and the dosage is usually customized as per the dog’s cancer type, overall size, and other factors, such as age and additional health conditions.
Cancer cells are quite sensitive to radiation, which is why this type of treatment is particularly effective at killing them. However, some amount of normal cell damage can happen because even if the radiation is specifically administered to a focal spot, it has to go through a number of tissues.
For example, in osteosarcoma cases, the radiation has to penetrate the skin and all of its layers, the muscles, fascias, as well as the superficial layers that exist on the bone. The animal’s skin is particularly sensitive to radiation, which is also why some dogs can develop local irritation and lose their fur in the areas where the therapy has been administered.
Types of Tumors That Respond to Radiation Therapy
Some cancers can be treated with surgery or chemotherapy or a combination of these two treatments, but others can be treated with radiotherapy. Unfortunately, there is a quite limited number of cancers that respond to it, such as the following:
- Mast cell tumors
- Squamous cell carcinoma
- Thyroid tumors
Having a talk with your veterinarian and a veterinary oncologist can help clear up any dilemmas you might have on whether radiotherapy might be appropriate for your dog’s type of cancer.
Once the staging of the neoplasm is discovered, the vet can recommend either radiotherapy or another type of treatment, such as chemotherapy The second is used particularly in cases where multiple cancer sites already exist, so it would be counterproductive and also detrimental to the animal if radiotherapy were to be employed in all of these body areas.
Types of Radiation Therapy
There are two main types of radiotherapy, and they are named after the purpose they are used for: adjuvant and palliative radiation therapy.
The first is typically employed for cancer cases where surgery is the primary elected treatment. However, depending on the area where the tumor is located and its spread to the surrounding tissue, the veterinary oncologist might recommend radiation therapy before the operation takes place. This makes it possible for the tumor to be easily operable in a procedure where all cancer cells are removed (so that it doesn’t return later on).
Palliative radiotherapy is used for cases where the tumors are actually inoperable. Because of their size or the pressure they put on surrounding organs, some neoplasms can significantly impact the dog’s quality of life. This type of radiation therapy is commonly utilized in brain tumors, for example.
How Often Should Radiation Therapy Be Administered?
This is an answer that only your veterinarian and veterinary oncologist can give you. However, in many cases, pet owners can expect a session per week for at least a month — especially in adjuvant radiotherapy.
The treatment is typically not administered more often than once a week as dogs have to be put under anesthesia to make sure that they do not move (even an inch) during the procedure. Mild sedation is an option, of course, but given that most pets should not go under general anesthesia more often than several times a year, and given its risks in geriatric patients, especially, once a week is the standard for most radiotherapy treatment courses.
What Side Effects Does Radiation Therapy Have on Dogs?
The adverse reactions that the patient can experience as a result of being treated for cancer using this method can be split up into two categories — early side effects and late side effects.
The most commonly encountered early ones are superficial modifications. Skin changes such as color modifications, irritations, and the appearance of the area being sunburnt are the most common of all.
If the area where the radiation is administered is the dog’s mouth, several changes can occur in this body region, too — such as halitosis, excessive drooling, ulcers in the oral cavity, and the development of bacterial infections as a result of the gums having entryways for these pathogens.
In nasal tumors, some early side effects can be seen, too, such as sneezing and discharge, while for eye neoplasms, corneal ulceration is a potential risk that must be taken into account.
As for the late adverse reactions that a dog can experience to radiation therapy, they usually show up about six months after the treatment sessions. Although their incidence is low, they can range from pathological fractures to non-healing wounds at the irradiated site.
How Long Does Radiation Therapy Last?
Unlike chemotherapy, which can sometimes be administered for the remainder of the dog’s life, especially if their tumor is inoperable, radiotherapy is given for a limited amount of time.
Most plans do not go beyond two to three months (maximum). This is because the local tissue can only stand a specific amount of radiation before serious side effects begin affecting it.
How Much Does Radiation Therapy for Cancer in Dogs Cost?
The price of an entire radiation therapy plan can be quite high, but it can vary from $2,000 to $6,000 or more. There are many factors involved, and given that some dogs might also have to be operated on or given chemotherapy at the same time, the cost could end up being higher.
Since cancer treatment is not affordable in any way, we strongly suggest getting pet insurance for your dog from their first months of life.
What Happens After?
Once the radiation therapy protocol is completed and the cancer is eliminated one way or the other, you will have to take your dog to the vet for regular monitoring.
As is the case for human cancer patients, dogs have to be taken to the animal hospital for check-ups to make sure that they remain as healthy as possible throughout the treatment and after it has ended.
The dog also has to be tested and diagnosed on occasion to prevent and quickly treat cancer recurrence, if it happens.