Back

WHAT IS CANCER ?

First broadcast on www.provet.co.uk  


This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Cancer is a word that conjures up fear, but it is often misused and not well understood

There are several words that are in common use to describe unusual "lumps" and "bumps", and which have overlapping meanings :

  • A growth - is a term often used to describe any abnormal tissue mass 
  • A tumour - is used to describe a tissue swelling, or mass
  • The term neoplasm literally means a "new growth" and neoplasia is used to describe an abnormal tissue mass which grows outside the body's normal control of tissues. A neoplasm has 3 main features :
    • It grows excessively
    • It does not respond to the body's control mechanisms
    • It continues to grow even after the initial cause has gone

    Neoplasms can be :

    • Benign - these grow slowly, remain localised in the tissues in which they form, resemble the tissue in which they form, they often have a capsule around them, they  rarely cause serious clinical signs and never spread to other parts of the body. 
    • Malignant - these may not resemble the tissue in which they form, they often grow rapidly, and many do spread to other parts of the body (a process called "metastatic" or "secondary" spread). 
  • A cancer is the commonly used term for a malignant neoplasm. 

So, when used properly, the term cancer does imply a serious situation, because the diagnosis of a malignant neoplasm has been made. 

Cancers can occur at any age, but most forms of cancer are more common in older animals.

What causes cancer ? For many types of cancer the underlying cause is not known, but some of the known causes include :

  • Exposure to substances (called carcinogens) which cause neoplasia 
    • Chemicals - many pollutants
    • Physical agents - radiation eg ultraviolet radiation in sunlight, XRays, radioactive radiation
    • Viruses - eg feline leukaemia virus (FeLV)
  • Genetic inheritance. It is now known that certain individuals are predisposed to develop cancer through inheritance. Click here for information about dog breed susceptibilities to develop cancer. 

Whether or not a cancer can be successfully treated, or whether it is life-threatening or not, depends upon several factors :

  • The type of cancer. Some cancers are highly malignant and carry a much higher risk, and a poorer prognosis than others. For example, malignant melanoma in dogs is much more difficult to treat successfully than lymphoma.
  • The location of the cancer in the body. If it involves (initially or through secondary spread) a vital organ system such as the brain, the lungs, the heart or liver, it is more likely to be life-threatening.
  • How advanced the disease is at the time the cancer is diagnosed. Even highly malignant cancers can be successfully treated if they have not spread to other parts of the body at the time they are diagnosed and treatment is started immediately.
  • The state of the animal to overcome the disease. Very old, weak animals, animals with other diseases, or animals with a poor immune system will find it harder to overcome a cancer than young, healthy animals.

It is important to realize that nowadays MOST FORMS OF CANCER can be treated with a reasonable likelihood of a satisfactory outcome.

How are cancers treated ? There are many different forms of cancer treatment, and the choice depends upon the type of cancer, how advanced it is, and it's location.  The most common forms of treatment (which are often used in combination) are :

  • Surgical removal
  • Anti-cancer drugs 
    • chemotherapy
    • immunotherapy
  • Radiation therapy
  • Others - eg hyperthermia (heat treatment)
  • In the future genetic engineering and gene therapy may help us to prevent and treat various forms of cancer.

There are many other important facets to successful cancer treatment including providing pain relief, proper dietary management and an owners tender loving care throughout the treatment period.

Provet Advice

The most important factor in the successful management of cancer is early diagnosis and treatment. Many owners delay seeking veterinary attention when they see an unusual mass, especially if they have an old animal, because they are worried that if it is a cancer  the veterinarian may recommend euthanasia. Whilst euthanasia of course has to be reserved for very ill patients with little chance of survival, most cancers can be treated, so get a veterinary opinion as soon as you can.

 

Updated October 2013