Radiotherapy is the technique of using highly controlled blasts of radiation to kill tumor cells before they have a chance to multiply and spread throughout the body. Whilst the radiation is highly damaging to cancer cells, the healthy cells surrounding them are much more resistant to the therapy, meaning that healthcare professionals are able to readily target cancerous tissue. Due to their relatively small size, dogs are especially good candidates for the use of this therapy.

Prior to undergoing the actual procedure, the dog will have to go through several CT and MRI scans of the body to pinpoint the locations of the tumors. To begin the radiotherapy, the dog will be given a general anesthetic and secured to a 'sledge' (much like that used during the MRI/CAT scans) that will assist the radiotherapy machine with targeting the tumors. Next, the machine will send beams of high-energy radiation into the body from different angles, having them intersect at the site of the tumor. This prevents healthy tissue from receiving lethal doses of radiation whilst simultaneously ensuring that the cancer cells receive the full brunt of the radiation. After each tumor has received an appropriate amount of radiation, it is simply a matter of performing another series of scans to measure the results. Multiple treatments are typically administered at regular intervals, though the frequency and duration of treatments will depend on the dog’s condition.

The cancers best treated by radiotherapy are ones that are localized, as this makes it easier to target the tumors and decreases the total amount of radiation that the dog will be absorbing. Against more widespread cancers, it may be appropriate for a vet to recommend chemotherapy instead, as this takes a holistic approach that will kill cancers situated throughout the entire body. It may be the case that a vet will recommend chemotherapy and radiotherapy in conjunction with one another. Obviously, such diagnoses can only be made on a case-by-case basis. Against the relevant types of tumors, radiotherapy is typically extremely effective and results can often be seen within a matter of days.

As radiotherapy is non-invasive, there is virtually no recovery time. Although the beams of radiation may cause a sunburn-like rash or skin discoloration at the points where they entered and exited the body, this is completely normal and will not require any additional treatment in order to heal. Hair loss can also be experienced at these sites, but the hair will typically start to regrow within a couple of weeks.

In terms of measuring the effectiveness of the treatment, the vet will most likely book a series of follow-up exams over the coming months. These examinations will measure the effect that the treatment has had on the tumors themselves and determine whether or not it is necessary to utilize further radiotherapy. Typically, owners can expect the process to take approximately six months from beginning to end, with periodic checkups following on from that if needed.

Due to the complexity of the process and cost of equipment, the price for radiotherapy can typically range from $1,000 to several thousand dollars. Two of the main factors that determine the price are the virulence of the cancer being treated and how many follow-up sessions will be needed to completely eliminate it. This is roughly analogous to the price of chemotherapy, which can easily reach $5,000, depending on the number of treatments and size of the dog.

Radiotherapy is one of the most effective ways to treat localized cancers, offering a quick and relatively stress-free experience for the dog. However, there are several drawbacks that should be kept in mind when making the decision to pursue this course of treatment. Firstly, the healthy cells that grow to replace the dead tumors may take a while to appear, and can themselves be somewhat defective (leading to potential neurological problems or bone spurs, for instance). Another risk is the use of general anesthetic, which always poses a small but not insignificant threat of complications if your pet is old or has breathing difficulties.

Although many cancers are genetic in nature and are common in certain breeds, there are measures that can be taken to prevent the appearance of other tumors that owe their existence to environmental factors. Making sure that your dog is not exposed to hazardous substances such as toxic chemicals or dangerous particulates such as asbestos is a start. Secondly, making sure they have a generally healthy diet lifestyle can help ensure good health well into old age.