Radiotherapy – Providing New Options and New Hope

1 February 2007

Radiotherapy has been used to treat cancer in animals for over 50 years. However, this technology has only very recently become available in Australia. It is now offering new options and new hope to cancer patients where none existed less than a year ago.

The Southern Animal Referral Centre offers the first deep radiotherapy unit in Australia specifically for small animals. Traditionally vets in Australia have relied on surgery and chemotherapy to treat cancer in our pets. Whilst both of these treatments are very effective and widely used, there are some tumours and situations where radiotherapy is appropriate. Radiotherapy is very versatile and can be used alone or in combination with surgery and/or chemotherapy.

As with any new therapy, owners and practitioners often have questions about how and when it is most appropriately used, or even what it is.

So what is radiotherapy?

Radiotherapy is the administration of a measured dose of low-level radiation targeted at a site where it acts to destroy tumour cells. Just like surgery it is a local treatment and is given to target the tumour cells and a small area of surrounding normal tissue.

Radiotherapy targets cells that are rapidly dividing. Most tumour cells are rapidly dividing, making them sensitive to radiation. Because radiation affects all cells (in the treatment field) that are rapidly dividing, some normal cells will also be affected.

What are the side effects?

Side effects of radiotherapy will be seen when radiation is given in doses that will effectively treat cancer. These side effects are restricted to the area being treated and are generally do not cause any problems to the animal. Areas that are commonly affected include the skin, and other tissues containing rapidly dividing cells. Skin side effects are the most common (it is difficult to treat an area on the body without including the skin) and are similar to a sun burn. These develop towards the end of the 3-4 week treatment and they generally resolve of their own accord within 2-3 weeks after the completion of therapy.

What happens when my pet receives radiotherapy?

For curative intent radiotherapy the total dose of radiation is divided into a number of smaller doses called fractions, which are given daily Monday through Friday for 3-4 weeks. One of the most important reasons for using small fractions is to decrease the likelihood of developing side effects. The animals need to be perfectly still when the treatment is given so a general anaesthetic is required for each treatment. Boarding options are available for animals who do not live close to the Centre.

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