Introduction to tumours in birds
Birds occasionally do develop tumours but not all lumps on a bird is a tumour. Some are abscesses, caused by a localised infection. Others are fatty lumps (lipomas) which are just a collection of fat below the skin and are harmless although occasionally unsightly. A female bird may even appear to have a lump which turns out to be an unlaid egg. Even if the lump does turn out to be a tumour it is still not necessarily serious news. Many tumours are benign, which means that although they are a mass of cells growing where they should not, they are dividing relatively slowly and they will not migrate to any other parts of the body, thereby compromising other organs. These benign tumours can eventually cause a problem, in that they might press on nearby organs or blood vessels, but most of them will allow the bird to live a normal lifespan and will not be the cause of death, as a rule. A malignant tumour is another matter, although not necessarily a death sentence any more than it would be for a person. A lot will depend on where the tumour is and how aggressive it is.
Common malignancies in birds
Generally, the older the bird and the more purely bred it is, the more likely it is to develop a malignant tumour. Malignancies are not that common in birds but if one is diagnosed there are treatments which are either a complete cure or a palliative regime which will prolong life and make the bird more comfortable and may even give remission. Skin malignancies are sometimes encountered and these are more likely in birds that over-preen or pick at a particular point on their skin. This constant damage can cause cells at the point of injury to mutate and then they can become cancerous. Fibrosarcomas, although not technically tumours of the skin, are near the surface as a rule because they are tumours of the connective tissue. They are usually found on breastbones or where a limb meets the trunk. They are generally relatively slow growing and don’t tend to metastasize (spread to other areas of the body or other organs to cause secondary cancers) too much.
Internal tumours in birds
Internal organs can also develop tumours, most commonly the reproductive organs and the gut. Of these, the former are more likely to metastasize and in this case prognosis is very poor. In the gut, secondaries are a little less of a problem but of course a large tumour in the gut can close off the alimentary canal causing an obstruction, which will be fatal very quickly unless it can be reduced in size. The lymph system is also prone to malignancy and this is to all intents and purposes impossible to treat as the treatment is so harsh. Benign lymphatic tumours are also found and are treatable.
Treatment of tumours in birds
Treatments are available for malignancies in birds, but, as with people, they are quite harsh, long term and with no guarantee of success. Whereas with a mammal most internal organs are reasonably easily accessed for surgery, the shape of a bird’s body means that most organs are packed very tightly behind the breastbone and in some cases, for example the kidneys, surgery is so difficult as to be considered impossible for all practical purposes. If the tumours have developed secondaries, again surgery would be considered not advisable as the risks would be too great and it would not be in the bird’s best interests. If the tumour is benign, then most vets would advise leaving it alone unless it is causing other problems, such as an obstruction, difficulty breathing or if it is pressing on a nerve and so causing lameness or other mobility issue.
Surgery on tumours
The tumours which are best treated with surgery are skin malignancies and the fibrosarcomas, which are near the surface and easy to reach, even if it may mean amputation of a wing or leg. Quite rarely, a vet will attempt radiotherapy or chemotherapy. This is not really with any hope of cure but both treatments will shrink a tumour temporarily and give a few more weeks or months of comfortable life. Birds are generally so small that targeting the radiotherapy can be very difficult and so whole body radiation is used, which of course will knock out bone marrow as well, leaving the bird at risk of infection so it is used sparingly on much loved companion birds, as the quality of life is unlikely to be high.
Early detection will help
If the tumour is discovered at an early stage, treatment is more likely to be successful, mainly because the tumour will be a smaller size and also the bird will be in better general condition than if it has been suffering from the tumour for some time before its detection. Especially with tumours which cause obstruction, a bird can become very ill with loss of appetite and weight loss, leading to vitamin deficiencies, trouble with feathers and skin and leaving it open to infestations of mites and protozoa and infections from bacteria and fungi which it would in health have shrugged off with minimal treatment. Getting to know your bird and having it comfortable with being handled and checked over will make sure that any abnormalities will be detected quickly and even if at the end of the diagnostic process nothing can be done, at least you will be secure in the knowledge that your bird will not have been suffering unduly.