Knockout_Mice5006-300Do animals really need to be used in science experiments? Do laboratory animals suffer? Are there any alternatives? These are common questions my friends and family ask me when I talk about animal research, so I thought I would try to answer them here:

  1. Do animals really need to be used in science experiments?

When we – cancer researchers – decide to use animal models in our experiments, it is out of necessity. To understand how cancer develops and to find new treatments, we need to use models that best represent what happens in humans. This is why scientists use animals, such as mice or rats, who are surprisingly similar to us in terms of their genetics, physiology and development. These animals are easy to manipulate as well as breed and are easy to study because they have a short lifespan of only a few years. In fact, in Canada, it is a legal requirement to test new cancer drugs on animals before using them on humans.

Here’s a concrete example of how animal research helps us learn more about cancer and bring forth new treatments: in Canada, 88% of women diagnosed with breast cancer survive 5 years after the disease is detected (1). This great achievement is largely due to animal research. Thanks to experiments performed on rats in the 1950’s, researchers pinpointed the role of hormones in the development of breast cancer. Following these results, other researchers decided to test tamoxifen, a drug that modifies hormone levels in the body, as a new treatment against breast tumours. To determine whether the drug was safe to use on humans and whether it was efficient, they first treated rats and found that the onset of cancer was delayed. All of this work was necessary to help make tamoxifen one of the most successful and extensively used drugs in breast cancer treatment (2).

  1. Do laboratory animals experience pain when being used for cancer research?

As mentioned above, one important step in cancer research is to grow tumors in animals to better understand how cancer develops and/or how to treat it. The process can be stressful or painful depending on where the tumour is located. For example, tumours grown in the brain, bones or lungs may cause more discomfort to the animal than small tumors grown under the skin. In any case, it is important to mention that in Canada, like most other countries, researchers follow very strict guidelines to make sure animals are not subjected to unnecessary pain, distress or suffering (3). For example, animals need to be euthanized before they suffer too much or before the cancer is too advanced. The Canadian Council on Animal Care in science (CCAC), which includes veterinarians, scientists and animal activists, is responsible for defining these guidelines (3). These individuals work together to find better practices to increase animal well-being, inform the public about animal research, and develop alternative models to study diseases. These guidelines are enforced by independent veterinarians hired by research facilities, who not only ensure that scientists follow the guidelines, but also monitor the animals and treat any observed health issues.

  1. Are there any alternatives?

Animal models have limitations. For instance, they are costly and do not always accurately reflect the human disease. Thus, efforts are being made to reduce the number of animals used in any given study and to find alternatives, such as computer modeling, to study cancer whenever possible. I sincerely hope that we will find reliable alternatives in the future but, for the time being, animal research continues to play an important role in cancer research.

For further reading:

(1) Statistics concerning breast cancers in Canada can be found at

(2) For a website that gives a good review on animal research and its use in cancer research:

(3) Canadian regulations concerning animal research can be found at

This article was written by Catherine Brun. She completed her PhD in Zurich, Switzerland and currently works as a post-doctoral researcher in the lab of Dr. Dan Durocher at Mount Sinai Hospital in Toronto studying DNA damage. To learn more about Catherine and her research check out our Members page.

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