Benign and Malignant Tumors in Guinea Pigs
Tumors are the result of an abnormal multiplication of body cells, resulting in a growth, or lump of tissue, which may be benign (harmless) or malignant (spreading and dangerous).
Most types of cancer are not common in guinea pigs until they are four to five years old. After that age, between one-sixth and one-third of guinea pigs are known to develop a tumor. Guinea pigs that have been inter-bred (within relatives) are more prone to tumor and cancer development.
Treatment, if recommended, will depend on the type and location of the tumor or cancer. While the outcome for benign skin tumors is generally good, the general outcome for some cancers of the blood is poor and affected guinea pigs often live for only a few weeks after diagnosis.
Symptoms and Types
Lymphosarcoma, a malignant tumor of the lymphatic tissues, is the most common tumor in guinea pigs. It causes what is referred to as Cavian leukemia. Signs may include a scruffy hair coat and occasionally masses in the chest area and/or an enlarged liver or spleen.
As far as benign skin tumors, trichoepitheliomas are some of the most common occuring in guinea pigs, especially younger guinea pigs, often forming at the base of the tail. Younger guinea pigs may also develop skin tumors or leukemia, which is cancer of blood cells.
Tumors are caused by an abnormal multiplication of body cells. Certain guinea pigs are genetically predisposed to this abnormality.
You will need to give a thorough history of your guinea pig's health and onset of symptoms, along with as much family history as you have available to you.
Based on the location, some tumors are more easily diagnosed when the growths can be seen and palpated (examined by touch) externally. When the tumor or cancer is present in the internal organs, it will need to be diagnosed by X-rays or scans. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. A diagnosis can then be confirmed by the blood count and and an examination of fluids from the lymph nodes or chest cavity in cases of leukemia and lymphosarcoma.
Your veterinarian will likely recommend surgical removal of the tumor or cancer. In some cases, with benign tumors, the growth may be impeding blood flow or the normal functions of the surrounding internal organs. If the benign tumor is not affecting the body in a negative way and is not expected to grow, your doctor may allow for it to be left alone.
In cases of malignant growths, surgery may be necessary, but may not always be possible if the location is in a place of the body where surgery would do more harm than good, or if disturbing the tumor would release the cancer cells to spread more quickly into the body.
For skin tumors like trichoepitheliomas, surgical removal is routinely done. Treatments for leukemia or lymphosarcoma, on the other hand, are not viable options and the animals usually die a few weeks after the symptoms have become apparent.
Living and Management
A pet guinea pig that is recovering after tumor surgery needs attentive postoperative care, with adequate rest in a quiet environment for recuperation. Regular follow-up visits to your veterinarian will be necessary to follow your guinea pig's recovery progress.
There is no way to prevent tumors and cancers in guinea pigs.