The n/d diet—Hill's Pet Food Company introduced the first cancer diet for dogs called n/d. The diet contains increased protein and fat, decreased carbohydrates, increased omega-3 fatty acids, and increased arginine. The composition of the diet is: protein, 37 percent; fat, 32 percent; carbohydrates, 21 percent; arginine, 3.1 percent (647 mg/100 kcal); omega-3 fatty acids from fish oil, 7.3 percent (1518 mg/100 kcal). In controlled studies dogs with lymphoma (lymphosarcoma) that were being treated with chemotherapy and being fed n/d had increased survival times when compared with dogs being treated with the same chemotherapy medications and eating a controlled diet.

Similar findings were found for dogs with nasal and oral cancer that were treated with radiation therapy and eating n/d. The conclusions from this study showed that: survival time increased 56 percent; quality of life improved due to decreased pain from dogs treated with radiation; remission periods were longer; and metabolic changes seen in pets with cancer were reversed.

While these findings are quite impressive, there is no evidence this diet helps dogs or cats with other forms of cancer. Despite this need for additional research, it is likely any pet with any type of cancer could benefit from this or similar diets. However, there are three potential problems with diet n/d:

1. It is an expensive diet, especially for owners of large breed dogs.
2. It is only available in a canned variety, most likely due to the high fat content.
3. The protein source is an animal by-product, beef lung. (Owners who desire the most holistic and natural diet possible might object to this protein source.)

A homemade diet that approximates n/d can be attempted. However, due to the high level of omega-3 fatty acids in the food it is difficult (if not impossible) and expensive to prepare a similar diet at home.

Tofu (soy protein) protects the intestinal tract from damage that could occur with certain chemotherapy drugs and result in diarrhea. While not proven, tofu diets might be preferred for pets with cancer, especially those whose treatment regimen includes chemotherapy.

The homemade anticancer diet for dogs should have the following nutrient levels: protein, 35 to 40 percent; fat, 30 percent; carbohydrates, 20 percent. Cats can have higher protein and fat levels and minimal or no carbohydrates (cats do not have a strict dietary carbohydrate requirement). Antioxidants can be added to the diet. However, high doses might interfere with any chemotherapy medications, such as doxorubicin (Adriamycin), that work to kill cancer cells by oxidation. Several studies indicate high levels of antioxidants may help cancer cells grow and spread. For example, one study showed that cancer cells contain high levels of vitamin C, probably serving as an antioxidant to protect the cancer cell from oxidation. Because of the possibility of high levels of antioxidants interfering with treatment or cure, you should discuss this topic with your pet's oncologist prior to using increased levels of antioxidants.

Arginine decreases tumor growth and spread (metastasis); supplemental arginine is useful for pets with cancer. Glutamine may retard the cachexia (wasting) seen in many pets with cancer and may help protect against intestinal injury. However, some experimental studies have shown no benefit and occasionally increased vomiting or diarrhea in pets supplemented with glutamine. At this time, there is no clear-cut evidence for or against glutamine supplementation. The need for glutamine will vary from case to case.

Other recommendations include adding 60 to 100 mg of Coenzyme Q10 and 500 mg of vitamin E /450 kcals of food. The precaution mentioned above concerning antioxidants should be heeded.

Finally, many holistic veterinarians will add fresh vegetables (especially those high in indoles and antioxidants), such as broccoli, kale, cabbage, and fresh garlic. Other supplements can be used as needed. Your veterinarian can decide which additional supplements might be helpful after consultation with you and a thorough examination of your pet.

Diet For Dogs With Cancer

Note: Before you start to feed your dog or cat a home-prepared diet, it is strongly recommended you discuss your decision with your veterinarian or a holistic veterinarian in you area. It is essential you follow any diet's recommendations closely, including all ingredients and supplements. Failure to do so may result in serious health consequences for your pet.

• 1/2 cup raw tofu
• 1 cup boiled lentils
• 2 cups potatoes boiled with skins
• 2 teaspoons chicken fat or canola oil
• 1/10 teaspoon salt

Multivitamin/mineral supplement

This diet provides 775 kcal and supports the daily needs of a 25-pound dog. It also provides 43.9 gm of protein and 22 gm of fat. Adding 2 tablespoons canned sardines increases the protein content by 6.2 gm and fat content by 4.6 gm.

Variations

1. 1. Add arginine at 647 mg/100 kcal of food.
2. 2. Add omega-3 fatty acids (fish oil) at 1518 mg/100 kcal. This is very difficult to do, as the average omega-3 fatty acid capsule contains 180 mg. Work with your doctor to increase the fatty acid content as much as possible (adding fish such as salmon to the diet can help achieve this goal.)
3. 3. Occasionally substitute 1/3 pound of cooked chicken, turkey, or lowfat beef for the tofu (in which case the lentils can be eliminated).
4. 4. Occasionally substitute 2 cups rice or macaroni for the potatoes.
5. 5. Add fresh, raw or steamed vegetables to increase the level of natural vitamins and minerals, as well as add flavor. Most vegetables provide approximately 25 kcal per 1/2 cup.
6. 6. Add 4 bonemeal tablets (10-grain or equivalent) or 1 teaspoon of bonemeal powder to supply calcium and phosphorus with a multivitamin/mineral supplement. Follow the label instructions. Alternatively, use a natural product from Standard Process (1 Calcifood Wafer or 2 Calcium Lactate tablets) for each 2 bonemeal tablets.
7. 7. When possible, use natural vitamins made from raw whole foods, rather than synthetic vitamins (although both can be used in combination), as the natural vitamins also supply plant phytochemicals, enzymes, and other nutrients not found in chemically synthesized vitamins. Use either Catalyn from Standard Process (at a dose of 1 Catalyn per 25 pounds) or Canine Plus from VetriScience (following label dosages) as the natural vitamin in this recipe.

Diet For Cats With Cancer

• 1/2 pound chicken
• 1/2 large hard-boiled egg
• 1/2 ounce clams, chopped in juice
• 4 teaspoons chicken fat or canola oil
• 1/8 teaspoon potassium chloride
• 100 mg taurine

Multivitamin/mineral supplement

This diet provides 471 kcal, 53.1 gm of protein, and 27.4 gm of fat and provides the daily needs for a 15-pound cat.

Variations

1. Add arginine at 647 mg/100 kcal of food. This is a recommendation for dogs and has not been proven in cats.
2. Add omega-3 fatty acids (fish oil) at 1518 mg/100 kcal. This is very difficult to do, as the average omega-3 fatty acid capsule contains 180 mg. Work with your doctor to increase the fatty acid content as much as possible (adding fish such as salmon to the diet can help achieve this goal). This is a recommendation for dogs and has not been proven in cats.
3. Occasionally add . cup rice, macaroni or potatoes. However, cats do not have a proven need for dietary carbohydrates, and adding additional carbohydrates supplies substrate (food) for cancer cell.
4. Add fresh, raw or steamed vegetables to increase the level of natural vitamins and minerals, as well as add flavor. Most vegetables provide approximately 25 kcal per . cup. Many cats, however, will not eat vegetables.
5. Add 3 bonemeal tablets (10-grain or equivalent or 3/4 teaspoon of bonemeal powder to supply calcium and phosphorus with a multivitamin/mineral supplement, following the label instructions. Alternatively, use a natural product from Standard Process (1 Calcifood Wafer or 2 Calcium Lactate tablets for each 2 bonemeal tablets) as the natural vitamin in this recipe.
6. When possible, use natural vitamins made from raw whole foods, rather than synthetic vitamins (although both can be used in combination), as the natural vitamins also supply plant phytochemicals, enzymes, and other nutrients not found in chemically synthesized vitamins. Use either Catalyn from Standard Process (at a dose of 1 Catalyn per 10 pounds) or NuCat from VetriScience (following label dosages) as the natural vitamin in this recipe.

Cancer is among the most feared diseases by pet owner. For many owners, the diagnosis brings grief, uncertainty, fear, and a general feeling of hopelessness.

While it is true that cancers can result in the untimely death of our pets, not all cancers carry a poor prognosis. For example, many solid tumors, if diagnosed early, respond quite well to surgical removal before they have spread. In these instances, early surgery is curative.

Other cancers may not be diagnosed until they have already spread. In these instances, treatment may not cure the pet but instead will provide a comfortable, extended life. In this latter case, the goal is to prolong life, but also ensure the pet is comfortable and has a good quality of life in whatever time remains. For most pets, the diagnosis of cancer is not an immediate death sentence, but rather the chance to begin therapy. Few cancers truly spread quickly. By keeping up with regular veterinary examinations and laboratory tests, early diagnosis of cancer is possible in most dogs and cats.

WHAT CAUSES CANCER IN PETS?

There are actually several recognized causes of cancers in pets.

VIRUSES. In cats, the feline leukemia virus, feline sarcoma virus, and feline immunodeficiency virus directly or indirectly through suppression of the immune system cause cancer.

TOXINS. In dogs, exposure to certain chemicals including 2,4-D can cause cancer. Various food additives have also demonstrated carcinogenic activity in laboratory animals, prompting many owners to prepare food at home or select diets that do not contain these synthetic additives and preservatives.

VACCINATIONS. Doctors are now beginning to realize that in a very small percentage of cats, frequent immunizations may cause certain solid tumors to develop. This is a very controversial topic, and the exact reason why a very rare number of cats that receive vaccinations, or other injectable medications, develop cancer is not known. Current evidence suggests that in genetically susceptible pets, some component of the vaccine, or injection, may cause a local reaction that becomes cancer.

GENETICS. Some pets are genetically prone to cancers. For example, among dogs, the Boxer is well known to develop cancers at a much higher rate than other breeds. Large breed dogs such as Retrievers have a higher incidence of malignant tumors of the spleen and liver. These examples may be a result of the inheritability of certain types of cancers, similar to the situation that occurs with some types of cancers in people (retinoblastoma) that occur as a result of genetic defects.

AGING. Most cancers occur in older pets. The exact reason is not known, but it seems that these older pets may have decreased functioning of the immune system.

Normally, as cells divide, mutations arise. In most pets, these abnormal, mutated cells are killed by their immune systems. Cancers arise when the immune system fails to kill these mutated cells. This seems to occur at a higher frequency in older pets. On a cellular level, here is how cancer forms and spreads.

It is know that malignant cellular transformation is associated with a series of genetic changes occurring within the cell. Cells contain proto-oncogenes, normal sequences of DNA, which regulate cellular responses to external signals that stimulate cell growth and reproduction. Proto-oncogenes are called simply oncogenes if their level of expression is altered so that the cell gains the potential for malignant transformation. Oncogenes may be activated in an aberrant manner in several ways, including:

• Point mutations can occur as a result of cell damage, altering the behavior of normal genes.
• Amplification of oncogenes can occur, altering the processing of cellular signals.
• Tumor suppressor genes, normally acting to restrict cell proliferation, can be diminished, allowing the formation and spread of cancer.

Once these cellular defects occur, mutated (cancerous) cells can reproduce and spread, causing what is called "cancer."

PRINCIPAL NATURAL TREATMENTS FOR PETS
The main natural treatments are designed to boost the immune system and reduce the spread of cancer. These can be used in conjunction with conventional therapies, as they are unlikely to be effective by themselves in most patients. The natural treatments are widely used with variable success but have not been thoroughly investigated and proven.

NATURAL DIETS FOR PETS
While there are few controlled studies showing the value of diet in supporting the pet with every type of cancer, there are studies showing the benefits of dietary therapy when combined with conventional therapies in dogs with lymphoma and nasal tumors. Since this diet is designed to reduce the growth and spread of cancer, it is often recommended for dogs and cats with any type of cancerous disease.

Studies demonstrate that both people and pets with inadequate nutrition cannot metabolize chemotherapy drugs adequately, which predisposes them to toxicity and poor therapeutic response. This makes proper diet and nutritional supplementation an important part of cancer therapy. There are several metabolic derangements common in the cancer patient. First, cancer patients often have hyperlactatemia (increased lactic acid in the blood). Additionally, since metabolism of simple carbohydrates produces lactate, a diet with a minimum of these carbohydrates might be preferred.

Research has shown a pronounced decrease in certain amino acids such as arginine in the plasma of cancer patients. If left uncorrected, these amino acid deficiencies could result in serious health risks to the patient. Supplementation with the deficient amino acids might improve immune function and positively affect treatment and survival rates.

Weight loss often occurs in cancer patients as a result of cachexia (wasting). Most of the weight loss seen in cancer patients experiencing cancer cachexia occurs as a result of depleted body fat stores. Tumor cells, unlike normal healthy cells, have difficulty utilizing lipids for energy. Dogs with lymphoma fed diets high in fat had longer remission periods than dogs fed high carbohydrate diets.

While there are often many treatment options for the various malignancies experienced by our patients, we often overlook the simple aspect of nutrition. Prevention and treatment will in the future most likely focus on nutrition in veterinary medicine, just as our counterparts are now doing in the human medical field. The research is out there: There is no doubt that cancer patients have deranged nutrient metabolism that can negatively affect the outcome of conventional therapies. Additions of omega-3 fatty acids and antioxidant vitamins and minerals to the diet of cancer patients may help improve survival and possibly decrease the chances of pets contracting cancer in those who are currently cancer-free.

Next month we will talk about the different diets available for pets with cancer.

ANTIOXIDANTS FOR PETS

Certain vitamins and minerals function in the body to reduce oxidation. Oxidation is a chemical process that occurs within the body's cells. After oxidation occurs, certain by-products such as peroxides and "free radicals" accumulate. These cellular byproducts are toxic to the cells and surrounding tissue. The body removes these by-products by producing additional chemicals called antioxidants that combat these oxidizing chemicals.

In disease, excess oxidation can occur and the body's normal antioxidant abilities are overwhelmed. This is where supplying antioxidants can help. By giving your pet's body extra antioxidants, you may find it possible to neutralize the harmful by-products of cellular oxidation.

Several antioxidants can be used to supplement pets. Most commonly, the antioxidant vitamins A, C and E, and the minerals selenium, manganese and zinc are prescribed. Other antioxidants, including N-acetylcysteine, Coenzyme Q10, Gingko biloba, bilberry, grape seed extract, and pycnogenol may also be helpful for a number of disorders. There is no "correct" antioxidant to use. Dosage varies with the specific antioxidant chosen.

Following is a brief discussion of a commonly used group of antioxidants called bioflavonoids/proanthocyanidins.

Proanthocyanidins are naturally occurring polyphenolic compounds found in plants; most often products containing proanthocyanidins are made from grape seed or pine bark. Proanthocyanidins are also called pycnogenols or bioflavonoids, a class of water-soluble plant coloring agents. While they don't seem to be essential to life, it's likely that people and pets need them for optimal health. These compounds are used for their antioxidant effects against lipid (fat) peroxidation. Proanthocyanidins also inhibit the enzyme cyclooxygenase (the same enzyme inhibited by aspirin and other nonsteroidal medications); cyclooxygenase converts arachidonic acid into chemicals (leukotrienes and prostaglandins), which contribute to inflammation and allergic reactions. Proanthocyanidins also decrease histamine release from cells by inhibiting several enzymes.

Proanthocyanidins, by potentiating the immune system (via enhancement of T-lymphocyte activity and modulation of neutrophil and macrophage responses), are often recommended for use in the treatment of pets with cancer.

Some research suggests pycnogenol seems to work by enhancing the effects of another antioxidant, vitamin C. Other research suggests the bioflavonoids can work independently of other antioxidants; as is the case with many supplements, there probably is an additive effect when multiple antioxidants are combined. People taking pycnogenol often report feeling better and having more energy. This "side-effect" may possibly occur in our pets as well.

Quercetin is a natural antioxidant bioflavonoid found in red wine, grapefruit, onions, apples, black tea, and in lesser amounts, in leafy green vegetables and beans. Quercetin protects cells in the body from damage by free radicals and stabilizes collagen in blood vessels. Test-tube and animal research also suggests quercetin might be able to help prevent tumors in hamsters or enhance the effects of cancer-fighting drugs.

Quercetin appears to be quite safe. Maximum safe dosages for young children, women who are pregnant or nursing, or those with serious liver or kidney disease have not been established; similar precautions are probably warranted in pets.

In people, a typical dosage of proanthocyanidins is 200 to 400 mg three times daily. Quercetin may be better absorbed if taken on an empty stomach. The suggested dosage of proanthocyanidins complex in pets is 10 to 200 mg given daily and divided into two or three doses. The suggested dosage of bioflavonoid complex in pets is 200 to 1500 mg per day, divided into two to three doses. The actual dosage of each product will vary with the product and the pet's weight and disease condition.

Because some types of chemotherapy and radiation therapy may rely on cellular oxidation for their effects, antioxidants should not be used without veterinary supervision in pets with cancer undergoing chemotherapy or radiation therapy.

CONVENTIONAL THERAPY

Conventional therapies for pets with cancer make use of a combination of surgery, chemotherapy, and radiation therapy.

Surgery For Pets
Surgery is the treatment of choice for solid tumors. Surgery can be curative if the entire solid tumor can be removed before it has metastasized (spread throughout the body by way of blood or lymphatic vessels). In the case of most small skin tumors, surgery is curative. When the entire tumor cannot be removed, surgery can be used to "debulk" the tumor (debulking removes as much of the tumor as possible). After debulking, additional therapy (chemotherapy or radiation) is used in an attempt to kill any remaining cells, as well as any cells that may have already spread from the original cancer site.

But does every tumor need to be removed? Of course not! Many of the pets seen for cancer consultations have benign fatty tumors, cysts, or warts that usually do not require surgical removal. With rare exception (an obvious wart), the only way to determine whether the lump is a benign lesion or a malignant cancer is through a biopsy.

Fortunately, most lumps are easily biopsied in the office with a small needle, in a procedure called aspiration cytology. In this procedure, a small needle, typically a 23 to 25-gauge needle, is gently inserted into the lump. The doctor aspirates a few cells or small amount of fluid, which are placed on a microscope slide, stained, and examined in the office.

Within minutes the doctor can usually tell whether the lump is benign or malignant. Most benign lumps grow slowly if at all and don't usually need removal. Malignant masses should be removed as soon as feasible after additional testing (x-rays, blood tests) has been done to determine if the cancer has spread.

It is vital that all lumps be biopsied! Some doctors diagnose tumors as "cysts" or "fatty tumors" by only looking or feeling the lumps; some of these in fact turn out to be malignant tumors when biopsied. The only mass that can be correctly diagnosed by visual inspection is the common papilloma or wart. All other masses, both benign lumps and cancerous tumors, look and feel the same. If your doctor says the lump doesn't need to be biopsied, get a second opinion!

Some tumors are so large by the time of diagnosis, or are in a location making surgery difficult if not impossible, that surgery is not an option. In these cases, some other form of treatment must be performed. To make the surgery as safe as possible, a thorough diagnostic workup including blood tests must be done prior to anesthesia.

Radiation For Pets
Radiation involves the use of radioactive materials, usually some type of x-ray, to kill the tumor cells. It can be used alone or in combination with surgery or chemotherapy. Radiation is not effective against every type of cancer, so it's necessary to work closely with a radiation specialist to determine which tumors are radiosensitive and are most likely to respond to this form of therapy.

Most pets tolerate radiation therapy quite well, but treatments usually require full anesthesia to administer the radiation. Common side effects of treating tumors with radiation include hair loss, burning of the skin, and discoloration of the skin. A new form of therapy for dogs with lymphosarcoma is whole body irradiation. In this procedure, the dog is anesthetized and half of the body is irradiated. Several weeks later, the procedure is repeated and the other half of the body is irradiated. The procedure has been reported to give dogs with lymphosarcoma a longer life expectancy (two to three years) than with conventional chemotherapy (12 to 18 months). The most common side effects, which last one to two weeks, are nausea, vomiting, diarrhea, and lethargy. Nutritional support and herbal therapies can be useful to minimize side effects of whole body irradiation, as well as any other radiation therapies for the pet with radiosensitive cancers.

Chemotherapy For Pets
Chemotherapy is effective against many but not all tumors. As is the case with radiation therapy, some cancers are sensitive to chemotherapy whereas others are not. Usually the goal of chemotherapy is not to cure but rather to prolong life before the cancer returns. Unlike the case with people, side effects of chemotherapy, such as vomiting and hair loss, are rare. However, pets must be monitored closely for other, more serious side effects. These side effects vary with the actual drug used, but include kidney disease, heart disease, and bone marrow suppression. Working with a knowledgeable cancer specialist is critical. Most pets do quite well with chemotherapy and suffer few side effects. Nutritional support and herbal therapies can be useful to minimize side effects of chemotherapy.