Chemotherapy

At Seaforth Veterinary Hospital

What is cancer

The words cancer and tumour are synonymous. Even a wart is a form of tumour. The distinction of importance is whether the tumour is benign i.e. will just sit there and cause no real problem, e.g. with fatty growths, lipomas or malignant. Malignant tumours can spread about the body, invade healthy tissue, and interfere with normal body functions. This is when the animal becomes ill
Cancer is no more than faulty cell reproduction in the body. Here cells divide beyond the normal limits of the body's requirements. Anything that can damage cellular DNA (the genetic material in a cell's nucleus) can cause cancer. Cancer cells are cells of your pet, they are not some foreign horrible invading monster. The problem is that these cells may invade normal, essential tissues of the body causing organ failure ( e.g. liver, kidney, lung) or pressure build up (e.g. if inside the skull or spine) both of which can cause pain and make our pets ill

How can we treat it

Cancer is a condition for which medical science has single-mindedly sought a cure. However it is useful to view it from another perspective. If we re-define this disease as no more than a chronic disease (just as diabetes is) it helps us deal with its treatment. The question then becomes "How are we going to control it?" rather than "How are we going to cure it", just as we control, and do not cure diabetes

Historically

For a long time surgery has been the mainstay of cancer therapy in veterinary medicine. In many cases it can be curative, but there are also many situations where it is simply impossible to consider surgery, such as when there is no well-defined single lesion to remove. Previously, such cases were essentially a death sentence to the animal


So what's new

These days chemotherapy and radiation therapies are realistic options either as single mode treatments (e.g. chemo and lymphosarcoma, thyroid tumours and radiation treatment). More often than not we use them in conjunction with surgery. The purpose of this adjunct to surgery is an attempt to "mop up" any residual tumour cells that surgery may leave behind, or simply to attack small secondary lesions that may have spread from the primary location


Treatment worse than the cure

A lot of people baulk at the idea of chemo or radiation therapy in their animals. This normal reaction is often a result of their own personal experience of a human that has undergone such treatments
I often stress to clients that chemotherapy in cats and dogs has few side effects! The worst is usually mild lethargy for a day or so following treatment. Quality of life during chemotherapy is often very good. Furthermore the field is rapidly expanding and new drugs are emerging that can specifically target cancer cells pathways sparing the bodies normal cells, as a results the future is bright for minimal side effects and maximal efficacy

Does this mean that cats and dogs have something humans do not? No. In humans, chemo doses tend to be pushed to their toxic limits, whereas in small animals we keep away from this extreme, and as a result side effects are often minimal, much to the surprise and relief of the client

What can I do to help

As in human medicine, the key to best outcomes is early diagnosis. Early diagnosis not only makes treatment simpler, it is more effective
To achieve early diagnosis we need your help

This means

Ensure your pet gets a full health check twice a year, especially in their senior years, get along to the Seven Plus check

Get the vet to check out any suspicious lumps or clinical signs you may have noticed in/on your pet

Keep in mind the long established principle that prevention is far better than cure


Outlook following treatment

Tumours come in all forms, sizes and distributions. Some are curable. This is of course our ultimate aim if at all possible. For those we cannot cure, we control.

This control is not indefinite, as tumours that cannot be cured often will return at a later date and at that stage are often none responsive to chemotherapy. It's like a survival of the fittest in the cancer cell world. Some cells develop drug resistance. It is for this reason chemotherapy is a mixture of drugs. It reduces the opportunity for cells to become resistant

Being honest from the outset is important. Chemotherapy will not control a tumour forever

It is important to keep in mind the principle that 1 of our years is equivalent to 7 years in their life, for the older cat or dog. So if a vet can offer your pet another 6 months of remission, this is like your doc offering a treatment that will extend your life by 3-4 years! A pretty good deal made all the more so in that almost invariably there is good quality of life during treatment