Cancer and your Pet
Lymphoma is a cancer made of Lymphocytes. These Lymphocytes readily travel throughout the body via the Lymph System. Lymphoma is not considered to be a localized disease, therefore surgery is an inappropriate treatment. A Biopsy may be performed in order to learn as much as possible about the tumor, whether it is fast or slow growing, what type of Lymphocytes it involves, etc.
Feline Lymphoma, at this time, is the most common malignancy, accounting for as much as 30% of all feline cancers. The most common form of Feline Lymphoma is the intestinal form. Cats with Lymphoma tend to range from 9 to 13 years old. They also tend to have a chronic history of weight loss, vomiting, or diarrhea, or all three at once. There are other forms of Feline Lymphoma as well. These include Renal (Kidney) Lymphoma, Nasal Lymphoma, and Mediastinal Lymphoma.
Nasal Lymphoma in a Feline
Nasal Lymphoma is rare but needs to be mentioned because it can potentially be localized (meaning it can be in one area and not have spread just yet). With Nasal Lymphoma you may notice nasal swelling, sneezing, and discharge.
Cutaneous Lymphoma in a Canine
Canine Lymphoma occurs mostly in middle aged dogs.. You may notice enlargements throughout the body, specifically Lymph Nodes. Your Veterinarian may request a blood panel to assess your pets health. Eventually the cancer will infiltrate an organ to the extent that the organ will begin to fail. Often times this is in the bone marrow or the liver. You will begin to notice appetite loss, vomiting and diarrhea may also arise. At this point your pet may be very weak, the tumor may become resistant to therapy, and no further remission can be obtained.
Some pets may develop growths in their mouths. These growths can be benign or malignant. Once the mass is noticed, it is highly recommended to have your pet checked by your Veterinarian.
Pets that have non-malignant tumors can usually be managed by surgical removal and continuous check ups on the area. Malignant tumors usually need more aggressive surgery and/ or radiation and chemotherapy, to decrease the probability of the tumor spreading.
Many pets will not show any signs of an oral mass or tumor until the mass has grown to inhibit their chewing or swallowing. You may also notice extremely bad breath, excessive drooling, or bloody oral discharge.
In order to be diagnosed, your pet must have your vet perform an exam. They may also perform an exam of the regional Lymph Nodes and potentially take chest X-Rays. In most cases the tumors are removed and a Hystopathology is done. This is to determine whether or not the growth is benign or malignant, as well as the type of cancer that your pet has.
The prognosis is directly related to the type of Cancer your pet has. With treatment, pets with benign tumors usually lead a normal life span. Pets with aggressive malignant tumors may have a shortened life span.
Adenocarcinoma (Mammary Gland Tumors)
In order to help protect your pet from mammary tumors you need to spay them. A female cat or dog that is spayed before their first heat cycle (this usually occurs around 6 months old), reduces the chances of a tumor developing by 90%. We suggest spaying you pet at 4 months of age (that is the soonest we will perform a spay). If your pet is allowed 1 heat cycle, the hormones that are released during this heat cycle then give your pet a 70% chance of not developing a tumor. (This is a 20% difference, just from allowing 1 heat cycle.. this is a dramatic difference!)
Mammary tumors are promoted by female horomones, therefore spaying your pet at any age is helpful in preventing tumors. Spayed females that develop tumors only have a 50% chance of the tumor being malignant.
The tumor can be either Tubular or Papillary, depending on the gland cells the tumor arises from. It can behave malignantly, but how aggressively malignant they are, depends on other characteristics (how quickly the cells appear to be dividing, how closely they resemble normal glands, etc.). Normal Glands should be soft and pliant, especially towards the rear legs. No firm lumps should be noticed. If lumps are detected you should schedule an appointment with your Veterinarian as soon as possible.
What else determines prognosis?
- Size of Tumor- tumors with diameters that are larger than 1.5 inches, have a worse prognosis than tumors smaller than 1.5 inches.
- Evidence of spread to the Lymphatic System carries a worse prognosis.
- History of rapid growth carries a worse prognosis.
This is the most common bone tumor in the Canine species. Osteosarcoma usually strikes the leg bones of larger breeds, occurring in middle aged or elderly dogs (but can occur at any age!). It is a fast spreading tumor that can spread to the lungs in a malignant process called Matastasis.
- When Osteosarcoma is found in a radiograph, it creates some characteristic findings:
- Lytic Lesions- look like an area of bone has been eaten away
- Sunburst pattern- shows a corona effect as the tumor grows outward and pushes the more normal bone up and away.
- Pathologic Fracture- may be seen through the abnormal bone
Axial Osteosarcoma - this is the term used for Osteosarcoma originating in bones other than limb bones. It most commonly affects the upper and lower jaw bones.
Treatment of Osteosarcoma
- Treating the pain (they are usually euthanized due to the severity of the pain)
- Amputation of limb - removal of the affected limb resolves the pain (even with amputation, the osteosarcoma may spread) your pet will be comfortable until the inevitable happens