Tumours (cancers) in hamsters may be present internally or externally. If they are external they will be noticed easily as abnormal lumps. These masses may be soft or hard, may or may not seem to be infected, (bleeding/ discharge/ smelly) and may or may not cause discomfort to the hamster, (discomfort will be apparent if for example the hamster is grooming the area excessively and causing baldness or self inflicted injury, or perhaps the hamster will move abnormally or stop eating.)
Internal tumours are less easily spotted even by the most dedicated owner and will usually only be found once they are large enough to cause the hamster to stop eating or lose condition and become noticeably sick. Your vet may then be able to palpate the tumorous growth especially if it is present somewhere in the abdominal cavity. The most commonly found internal tumours include intestinal polyps and kidney tumours. Lymphosarcoma is also found in hamsters; this is a very aggressive type of cancer.
Unfortunately by the time internal tumours are noticed and subsequently diagnosed it is often too late to treat them and the hamster may be suffering. In this case it may be kindest to consider euthanasia of the hamster to prevent further suffering when there is no effective treatment available. If surgery is an option do be aware that it may not be successful . Due to the small size of these animals making them more susceptible to shock and the difficulty of performing internal surgery there is a high risk associated with surgical and aneasthetic procedures in these pets. Cost may also be something that pet owners have to consider when choosing whether or not to opt for surgery. Discuss all your concerns with your vet who will be happy to help you decide the best course of action. If the hamster seems to be well and thriving despite the presence of an internal growth it is perfectly acceptable to allow the hamster to live out it's natural life-span.
External tumours often have a more favorable outcome than internal ones. It is often possible to remove external tumours under general aneasthetic. It is wise to send a sample of the tumour to the laboratory to find out exactly what kind of growth it was. A better prognosis can then be given regarding the likelihood of the tumour recurring or having spread to other parts of the body.