More Facts about Cancer

What is Cancer?

How Common is Cancer?

How is it Diagnosed?

Is Cancer Preventable?

Other Types of Cancer in Pets

How is Cancer Treated?

What is the Success Rate?


Detecting the Signs of Cancer.


What Causes Cancer in Dogs?

What is the Cost of Cancer Treatment?


What are the Side Effects of Chemotherapy in Pets?

Diagnosis and Staging.

Treatment Strategies

Deciding on Treatment Options

Tumor Biology and Natural History.

Goals of Treatment.

Supportive Care.

What is Cancer? Go to Top of Page
Cancer is an uncontrolled growth of abnormal cells on or within the body. Cancer may be benign or malignant. It may be localized or it may invade adjacent tissue and spread throughout the body.


How Common is Cancer? Go to Top of Page
Cancer is common in pet animals and the incidence increases with age. Cancer accounts for almost half of the deaths of pets over 10 years of age. Dogs get cancer at roughly the same rate as humans, while cats get fewer cancers.


How is it Diagnosed? Go to Top of Page
Strong circumstantial evidence of cancer can be attained from x-rays, blood tests, ultrasonography, the pet's physical examination and medical history. Most cancers, however, will require a biopsy (a removal of a piece of tissue) for confirmation that cancer exists and to grade the level of severity from benign to aggressively malignant.


Is Cancer Preventable? Go to Top of Page
Unfortunately, the cause of most cancers is not known and, therefore, prevention is difficult. Early detection and treatment are the best ways to manage cancer in pets.


Other Types of Cancer in Pets. Go to Top of Page

Skin - Skin tumors are very common in older dogs, but much less common in cats. Most skin tumors in cats are malignant, but in dogs they are often benign. Your veterinarian should examine all skin tumors in a dog to determine if any are malignant.

Breast - 50% of all breast tumors in dogs. Spaying your female pet between 6 and 12 months of age will greatly reduce the risk of breast cancer. Surgery is the treatment of choice for this type of cancer. Spaying your pet at the time of cancer surgery has been shown to improve prognosis. Follow up treatment may be recommended.

Head & Neck - Cancer of the mouth is common in dogs. Signs to watch for are a mass on the gums, bleeding, odor, or difficulty eating. Since many swellings are malignant, early, aggressive treatment is essential. Cancer may also develop inside the nose of dogs. Bleeding from the nose, breathing difficulty, or facial swelling are symptoms that may indicate cancer and should be checked by your veterinarian.

Testicles - Testicular tumors are rare in cats and common in dogs, especially those with retained testes. Most of these cancers are preventable with castration (neutering) and curable with surgery if done early in the disease process.

Abdominal Tumors - Tumors inside the abdomen are common but it is difficult to make an early diagnosis. Weight loss or abdominal enlargements are signs of these tumors.

Many of the above signs are also seen with noncancerous conditions but they still warrant prompt attention by a veterinarian to determine the cause. Cancer is frequently treatable and early diagnosis will aid your veterinarian in delivering the best care possible.


How is Cancer Treated? Go to Top of Page
Each type of cancer requires individual care and may include a combination of treatment therapies such as surgery, chemotherapy, radiation, cryosurgery (freezing), hyperthermia (heating) or immunotherapy. Once you have a diagnosis, your veterinarian will discuss the best treatment option(s) for your pet. In some instances, your veterinarian may refer you to a board-certified oncologist (cancer specialist) depending upon the recommended course of treatment.


What is the Success Rate? Go to Top of Page
This strongly depends upon the type and extent of the cancer, as well as the aggressiveness of therapy. Some cancers can be cured and almost all patients can be helped to some degree.


Detecting the Signs of Cancer. Go to Top of Page
The signs of cancer vary depending on the type of cancer. Oral cancer is suspected if there is excessive drooling, difficult eating or swallowing, or bleeding from the mouth. Lung cancer is suspected if there is rapid and labored breathing. Digestive cancers may cause vomiting or diarrhea, or they suddenly stop eating. Bone cancer in limbs might cause lameness and stiffness. Any lumps and bumps on any parts of the body are cause of concern, especially if it is rapidly growing, is warm or painful, is ulcerated or bleeding, is irregular in shape or is well attached to the tissues under the skin. Sores and wounds on ears and nose that don't heal could be skin cancer. Chronic nasal discharge might indicate nasal cancer.

Detecting any of these signs and acting quickly is the first weapon for fighting cancer successfully. It is always better to be safe than to be sorry later. Some cancer is so aggressive that it might become too late when you finally take your pet to the veterinarian. When in doubt, act immediately.
If your pet is getting older, it is a good idea to routinely examine the body by stroking and petting and going over the entire body. Such regular grooming sessions will serve two purposes: Detecting "anything out of ordinary" as well as deepening the bond between you and your aging pet. An annual or biannual complete physical examination along with annual laboratory analysis (complete blood count, serum chemistry profile) and chest x-ray (radiograph) is also very useful in catching geriatric illnesses that affect the kidney, liver, heart or bowel.


What Causes Cancer in Dogs? Go to Top of Page
We know the cause of very few cancers in companion animals, however the Foundation is working very hard to change this. The development of cancer can occur in any organism from excessive exposure to carcinogenic agents such as certain chemicals, UV or X-irradiation and from some viral infections. Although we do not know the exact cause for each type of cancer in pets, the underlying problem is due to abnormal genes that result in uncontrolled growth of cells, which may invade into surrounding tissues or spread to other areas. The number of cancers that are actually heritable (capable of being passed on to offspring) is unknown in dogs but it has been occasionally documented.


What is the Cost of Cancer Treatment? Go to Top of Page

The cost of evaluation, diagnosis, staging and treatment will vary depending on the site of the tumor, the size of the pet, the type of treatment selected and how well your pet handles the treatment. In general, the initial evaluation including the diagnosis, staging and a discussion about the prognosis and treatment options may range from several hundred dollars upward if the tumor is located in a body cavity or hard to reach location. Major surgical procedures that require wide and deep tumor removal, or major reconstructive procedures, will likely range from about $1500 upward, depending on the extent of surgery and the recovery period. Chemotherapy costs vary with size of the pet but for many treatment regimens the cost of chemotherapy may range from several hundred dollars for palliative oral treatment to several thousand dollars over a 3-6 month period. Radiation therapy will range from approximately $2000 to $6000 depending on the type of radiation therapy and the region of the country.


What are the Side Effects of Chemotherapy in Pets? Go to Top of Page

The goal of chemotherapy in pets with cancer is to preserve the highest quality of life possible. However, there may be some side effects following treatment with chemotherapy. The overall impact of side effects is reduced by altering doses or eliminating drugs from treatment if side effects are significant. However, in order to obtain any benefit from chemotherapy it is necessary to use doses that can result in some reversible and temporary effects on normal tissues. The most common side effects of chemotherapy in pets include: Stomach upset resulting in a reduced appetite, nausea, vomiting, diarrhea and dehydration. These effects are generally mild and self-limiting but may require symptomatic treatment or hospitalization in some instances.


Diagnosis and Staging. Go to Top of Page
Your pet's general health status is assessed to identify disease which may adversely affect prognosis, and limit or alter therapy. After a thorough physical examination the screening laboratory evaluation generally includes a complete blood cell count, serum biochemistry panel, and urinalysis. Other general diagnostic tests are performed as indicated. Survey radiographs are indicated to detect metastasis, determine potential bone involvement, evaluate orthopedic soundness prior to amputation or limb-sparing in dogs with osteosarcoma, localize oral or nasal masses, etc.

Contrast radiographic studies can determine the extent of gastrointestinal and genitourinary neoplasia. Computed axial tomographic (CAT) scanning or magnetic resonance imaging (MR) are becoming more available and defines the invasive characteristics of deep seated tumors much more clearly than survey radiographs. CAT or MR imaging procedures are particularly helpful when planning involved surgical procedures. Ultrasonography can be used to determine the proximity of a tumor to large blood vessels, to determine the cystic nature of masses, to evaluate possible intra-abdominal metastases to lymph nodes or organs, and to assess the initial and post-treatment tumor volume.

The diagnostic plan for a suspected tumor involves the clinical evaluation described above as well as characterizing the tumor, the surrounding area and the rest of the body where cancer may have spread with x-rays, ultrasound or other imaging. The keystone of the diagnosis is a cytologic or histologic confirmation of malignancy.
Cytologic examinations of bone marrow aspirates, buffy coat preparations of peripheral blood samples and fine needle aspiration biopsies of accessible tumors and regional lymph nodes are important diagnostic procedures. Fine needle aspiration can be accomplished on any accessible mass. Often, a rapid, inexpensive diagnosis can be made for certain tumor types (lipomas, sebaceous adenomas, mast cell tumors). However, cytologic evaluation of fine needle aspirates or bone marrow specimens must not be over-interpreted. Treatment decisions should be based on a cytologic diagnosis only when a definitive diagnosis can be made such as with lymphosarcoma, mast cell tumors, etc.

Many techniques are available for tissue biopsy. The method selected should safely and simply procure adequate tissue samples to provide an accurate diagnosis without compromising treatment. Biopsies can be excisional (complete removal of the tumor) or nonexcisional (removal of only a portion of the tumor). Nonexcisional techniques include: a) cytology from a fine-needle aspirate, brush samples, impression smears or effusions, b) histopathology of cutting forcep biopsies, cutting needle biopsies, punch biopsies, and incisional biopsies.


Treatment Strategies. Go to Top of Page
Cancer specialists use a team approach to detect and treat complex cancers. Depending on your pet’s diagnosis, the cancer specialist will consult with other specialists, who may include surgeons, medical oncologists, diagnostic radiologists, radiation oncologists and other professionals who have been trained in treating cancer.

Whether your pet receives radiation therapy, chemotherapy, surgery or a combination of therapies, a customized treatment plan should be designed to most benefit your pet and suit your needs. Supportive care such as nutritional counseling and pain management can also be provided. Once treatment has been planned, a team of trained and certified health care professionals, including nurses, pharmacists, technologists and others should assist in your pet’s care. The clinicians and nursing staff should work as a team to monitor the treatment response and overall health of your pet. Seek bereavement services in your area to help with your emotional needs.


Deciding on Treatment Options. Go to Top of Page
The decision making process for management of cancer in pets can be a complicated and difficult process. The evaluation of the general health of the patient, the type of cancer, access to specialized treatments and the emotional, time and financial commitment to conduct the treatment must be carefully considered. The benefits, risks and costs cannot be adequately determined without some assistance and support. Such support is best obtained from family, friends and veterinary professionals. Once the general health of the patient has been determined to be adequate and the cancer has been clinically staged and biopsied, the next decision is to determine treatment options.


Tumor Biology and Natural History. Go to Top of Page
Rational treatment planning involves basic knowledge of the potential for local recurrence and metastasis of the neoplasm. The key is the histological assessment or diagnosis. Malignant tumors predisposed to local recurrence should be managed aggressively from the time of initial diagnosis. The chance for long-term tumor control is greatest when the tumor is undisturbed by previous therapeutic intervention. The risks and benefits of aggressive management must be carefully considered. However, most people will recognize the obvious benefit of prolonged tumor response with reduced overall expense if the tumor can be managed once, albeit initially more costly, compared to multiple, suboptimal attempts at tumor control.


Goals of Treatment. Go to Top of Page
Maintaining the highest quality of life for the longest period of time is always the goal of cancer management in companion animals. This goal must be considered within the context of emotional and financial factors. Decisions are often difficult.
The best service that can be provided is a knowledgeable, unbiased assessment of the condition and a frank discussion of options sufficient to permit an informed decision. This may involve consultation or referral to a specialist or a comprehensive cancer center. Curative therapy is designed to attempt permanent control of the tumor using aggressive but not excessively debilitating treatments. Multiple treatment modalities are often employed.

The decision to pursue curative treatment can be difficult. A working definition of curative therapy often used in veterinary medicine is the likelihood that a given tumor type will be controlled for at least 1 year following treatment. If the best available information suggests this is not possible, palliative therapy may be considered.

Palliative therapy is designed to reduce pain or functional difficulties such as swallowing, urinating or defecating without attempting to cure the tumor. The length of time is not as important as the quality of the time remaining for the pet. The hospital time and side-effects must be minimal for palliative therapy. Pets with cancer may also require supportive therapy such as antibiotics, medications to control some symptoms, blood transfusions and nutritional management.


Supportive Care. Go to Top of Page
Dogs that have cancer are generally middle aged or older. Age is not a disease but there often other health problems in older pets with cancer that must be managed simultaneously with the cancer. In addition, cancer can produce some problems in other organs such as anemia, kidney problems and digestive abnormalities. The complete management of cancer in dogs requires consideration of supportive measures. These supportive measures can be considered in several categories: nutritional considerations, blood product support and, ancillary medication for concurrent diseases or symptoms.

Pets with cancer require consistent, high quality nutrition. The specific nutritional needs for pets with cancer are not completely understood. The brands of the food are less important than a complete, balanced and palatable food for your pet with cancer.

A poor appetite and weight loss can result from cancer in several ways. Cancer can affect appetite, smell, metabolism and the physical ability to chew or swallow. Treatment for cancer may also reduce appetite by inducing nausea or irritation to the intestinal tract. Numerous means of dealing with nutritional issues in pets with cancer now exist and this aspect of management should be carefully considered with your veterinarian.

In some instances, pets may require transfusions of whole blood, red blood cells or plasma. This type of management is usually necessary on an acute basis and is rarely used for long-term support. Blood product transfusions are more available than ever before.

Many dogs diagnosed with cancer also have other health problems. Some health problems are minor and require little additional consideration after a cancer diagnosis is made. Others may profoundly affect the decisions about cancer management. The specific management considerations for dogs with concurrent medical problems should be thoroughly discussed.

Symptomatic medications are often necessary while cancer is being controlled. Some medications that may be necessary include anti-emetics, laxatives, anti-diarrheals, anti-histamines, cortisone-derivatives and others.
Antibiotics may be necessary to prevent or control bacterial infections at various times throughout treatment of cancer in dogs.

Close attention to the possibility of dehydration from vomiting, diarrhea or excessive urination is required for many patients with cancer. On occasion, fluid administration on an outpatient or inpatient basis may be required.