Hamsters have relatively short lifespans, living on average 2 to 3 years. Like humans, hamsters are more susceptible to age-related diseases such as cancer as they mature. Tumors are quite common in elderly hamsters.
Tumors can be located internally, such as in the bladder, or externally, appearing as a lump on the skin. All tumors can be either benign or malignant.
The presence of tumors in hamsters often is accompanied by loss of appetite, lethargy, weight loss, change in personality and sometimes hair loss or bleeding sores.
Female hamsters are more prone to developing internal, cancerous tumors due to their complex reproductive systems, according to PopularPets.net.
Theories and Speculation
The most common areas in which hamsters develop tumors appear to be on the skin and within the thyroid and adrenal glands, according to Ask-The-Vet.com.
According to the Animal Health Center, there is a chance that a skilled veterinarian can surgically remove small external tumors. Internal tumors are less likely to be treated with surgery.