July is Sarcoma Awareness Month

July 23, 2014
The wrist of a dog diagnosed with osteosarcoma.

The wrist of a dog diagnosed with osteosarcoma.

Both veterinary and human oncologists talk about three big families of cancer: carcinomas, sarcomas and tumors of the blood and lymphatic system. Carcinomas frequently originate from glands – like breast or prostate carcinomas. The most well-known tumors of the blood and immune system are leukemia and lymphoma. Sarcoma is a form of cancer arising from bones, tendons, muscles, nerves, joints, blood vessels and fat. Over 13,000 Americans were diagnosed with sarcoma in 2013. Sarcomas are rare in adults, but represent 15% of all childhood cancers.

Pets Get Sarcomas Too
Cancer registries for pets exist, but recording the types of cancer pets have is not mandatory as it is for human cancer diagnoses. Some information about the occurrence of sarcomas in pets has been published. In a survey of Greek dogs with skin cancer, 40% of the tumors were sarcomas, the two most common were mast cell tumors and fibrosarcoma. A study of American dogs found the mast cell tumor was the most common malignant tumor on this side of the Atlantic as well. An Italian tumor registry based out of Genoa found sarcomas occurred more commonly as a dog aged. Breed also influences the development of sarcomas. A survey of flat coated retrievers in the United Kingdom found 55% of malignant tumors and 26% of all tumors in this breed were sarcomas.

Common Dog Tumors with the Last Name Sarcoma
Osteosarcoma (bone sarcoma) is ten times more common in dogs than in humans. Large and giant breed dogs have a greater risk of developing osteosarcoma. In dogs, the tumor destroys the bone (see the above photograph) and to control pain, amputation is often recommended; although limb-sparing surgery and radiation therapy are also used to control pain. Coupling surgery or radiation with systemic chemotherapy helps to control the spread of osteosarcoma and thus prolongs survival.

Hemangiosarcoma is a tumor of blood vessels. Because the vessels are cancerous, they rupture easily and dogs with hemangiosarcoma frequently end up in the animal ER with catastrophic hemorrhage from a ruptured tumor in their spleen, liver or heart.

Soft tissue sarcomas include tumors whose name is a mouthful like hemangiopericytoma, or that sound like a more benign tumor, such as the nerve sheath tumor. Soft tissue sarcomas are a mixed group of tumors frequently of the skin and often lumped together because of a similar clinical course. These tumors send tentacles of tumor out into the surrounding tissue, making complete removal challenging. Successful surgical removal of a soft tissue sarcoma requires a much bigger incision than most dog owners expect in order to remove the tentacles. If residual tumor is left behind, these tumors commonly recur and may require radiation therapy to control.

Cat Tumors with the Same Last Name

An injection site sarcoma in a cat just prior to surgical removal.

An injection site sarcoma in a cat just prior to surgical removal.

An injection site sarcoma is a very specific type of sarcoma, most commonly found in cats where injections are administered, such as a vaccination or insulin injection. When these tumors develop on the nape of the neck (as in the photograph on the right) or on the hip, they are very difficult to completely remove and they recur much more frequently than soft tissue sarcomas of dogs. Most patients need follow up with radiation therapy, and because 25-40% of these tumors metastasize, chemotherapy as well.

Raising Sarcoma Awareness

  • Osteosarcoma causes bone pain and limping. Don’t assume your limping dog has a bum knee or weak ankles. Have your limping pet seen by your veterinarian.
  • Soft tissue sarcomas and injection site sarcomas often start as a skin lump. See your veterinarian for any lump that is enlarging over a month, is larger than 2 cm (3/4 inch) in diameter, or has been present for more than 3 months.
  • Sarcomas can often be diagnosed based on a fine needle aspirate. Help your veterinarian take the best care possible of your pet and allow this simple procedure if it is recommended.

Tripawds Awareness Day

March 5, 2013
Jill tripawd

Jill

Sunday was Tripawds Awareness Day on the cleverly chosen date of 3/3. To celebrate tripawds, I thought I would tell you about a triplet of tripawd patients.

Every veterinarian has dog and cat patients with only three legs, or as one website calls them, tripawds. Because I am a cancer specialist, my tripawd patients all have a malignant tumor as the cause of their amputation, but other veterinarians perform amputations to treat a variety of diseases and injuries. One common cause of amputation in cats is a serious fracture that cannot be repaired. Infections of the bone cannot always be cured by antibiotic therapy and if the infection starts to cause pain, an amputation controls both pain and infection. When hit by a car, dogs and cats may suffer nerve damage to their front leg, sometimes resulting in paralysis. The paralyzed limb may drag on the ground and develop sores. Amputation resolves this problem once veterinarians have determined there is no hope of the limb regaining function.

Handsome Lester

Lester, a refined gentleman of a dog, came to The Animal Medical Center nearly two years ago. He has the black tongue of a Chow Chow, the coat of a Samoyed and sadly, osteosarcoma. Osteosarcoma is the most common bone tumor in dogs and in my practice is the most common cause of amputation. Because amputation treats the tumor in the bone but does not treat the little tumors lurking elsewhere, like the lungs, Lester received chemotherapy intravenously for a few months after surgery. Then Lester exceeded our expectations and was tumor-free for over one year. Late last summer, chest x-rays picked up new tumors in his lungs. Thanks to an oral chemotherapy drug, tripawd Lester continues to exceed our expectations with a great quality of life – walking on the beach with his naughty brother Nicholi.

Long live Ajax

Ajax, a 10 year old tripawd Labrador, appeared in an earlier blog when he had two simultaneous tumors, a thymoma near his heart and a soft tissue sarcoma on his hind leg. The sarcoma attached itself to his leg bone and could not be removed without losing the functionality of his leg. Ajax’s soft tissue sarcomas behaved very differently than Lester’s osteosarcoma. Amputation was the only treatment required to cure him of this tumor and he has survived nearly three years since the surgery.

Cheerful Jill

Jill’s family desperately tried to save her leg. They let several pathologists study her toe biopsy and we were hopeful surgical removal of the toe would be all the treatment she needed. Several months after the toe amputation, Jill’s family found a hard mass on the back of her leg, and a biopsy indicated the giant cell osteosarcoma of the toe had recurred. Since the possibility of amputation was discussed during the evaluation of the toe biopsy, Jill’s family was not surprised at the recommendation for an amputation once the tumor had returned. We also recommended chemotherapy, the same drugs we used successfully in Lester. To hear more about Jill and her adventures, read her blog on Tripawds.com.

Want more information about tripawd dogs? 

  • In addition to the Tripawds website, there is also Canine Amputees. Their page of links is excellent.
  • Watch a video of a pair of bi-paws and their new rolling front legs.

National Pet Cancer Awareness Month

November 21, 2012

November is a busy month. Not only is it National Diabetes Month, but it is also National Pet Cancer Awareness Month.

Cancer and diabetes are two important diseases the veterinarians at The Animal Medical Center treat every day.

According to VPI, a pet insurance company, their top ten insurance claims for pet cancer treatment include tumors we veterinary oncologists commonly treat.

  1. Lymphoma or lymphosarcoma
  2. Malignant skin cancer
  3. Splenic cancer
  4. Bone or joint cancer
  5. Liver caner
  6. Chest cancer
  7. Bladder cancer
  8. Brain of spinal cord cancer
  9. Mouth cancer
  10. Cancer of the cells lining the inside of the chest and abdomen

Surgery and cancer

Surgery is often the first procedure for a cancer patient and is commonly performed to get a biopsy of a lump which leads to the diagnosis of cancer. For one or two of the tumors on the top ten list, surgical excision might be the only treatment needed to control the tumor. If surgical excision isn’t enough to control the tumor, we often recommend chemotherapy.

Chemotherapy concerns

The tumors listed in the top ten insurance claims also include tumors veterinary oncologists manage with chemotherapy treatments. Chemotherapy helps us control the spread of some tumors and shrink others, improving both the length and quality of a pet’s life.

Many pet owners express concern over the potential side effects of chemotherapy treatment on their pet. Scientific research has proven their concerns unfounded. Carboplatin, a chemotherapy drug used to treat bone tumors called osteosarcoma and other tumors in dogs and cats, receives high marks for improving quality of life.

A combination of chemotherapy drugs for the treatment of feline lymphoma also improved the quality of life of cats suffering from this common tumor.

Setting expectations

Veterinary oncologists successfully give chemotherapy to dogs and cats on a daily basis. Because we have been treating pets with cancer for decades, we know what doses are safe and what additional therapies to administer to limit adverse reactions. In my experience, dogs tolerate chemotherapy better than people and cats tolerate it even better than dogs. I think psychology plays a role in chemotherapy reactions. Humans know what chemotherapy can do. My patients, smart as they are, have no clue about chemotherapy. The typical pet receiving chemotherapy has one or two off days following treatment and then their appetite and energy rebound. We obsess over every patient’s white blood cell count and send them home without treatment if the count is too low for safe administration. Every one of our patients has at least two people helping with chemotherapy administration: someone who holds the pet on a soft, comfortable mat, and a nurse specially trained in administration of chemotherapy drugs.

What can a pet owner do about cancer?

Take an active role in screening your pet for cancer using the Veterinary Cancer Society’s Ten Common Signs of Cancer in Pets.

Investigate pet insurance to see if it is right for your family. If you already have a policy, find out if cancer treatment is covered.


Of Man and Dog: The Fight Against Cancer

June 7, 2012

Humphrey is available for adoption through Petfinder (see details below)

Dogs, surprisingly, retain physiological and genetic similarity to humans. Dogs and humans also share a common environment and suffer from the same diseases, such as cancer. In many cases, studying dog cancer can lead to advances in the treatment of human cancer.

Strike it rich with Golden Retrievers

Take for example the Golden Retriever, with a lifetime risk of lymphoma in the United States of 1:8. Veterinary researchers collaborated and struck “research gold” when they found a deletion in a canine chromosome in a high percentage of Golden Retrievers with B cell lymphoma. The same deletion was found less often in other breeds with lymphoma.

Because genetic abnormalities in human cancers are difficult to pinpoint, studies such as this one help to identify genetic abnormalities to target in future human studies of lymphoma. A newer study employed a virtual rearrangement of chromosomes from Golden Retrievers and other breeds to match the distribution of genes on human chromosomes and identified human chromosomes 8 and 21 as areas for further study to advance knowledge and treatment of human lymphoma.

Research of this caliber requires multiple investigators, each contributing to the work from their own area of expertise. To help decipher this information, I spoke with my friend and one of the investigators, Dr. Jamie Modiano.

He says, “If, at the molecular level, you look at dog lymphoma pretending it is human lymphoma, the genetics are simpler and it becomes easier to find pertinent abnormalities. The molecular abnormalities stand out in the dog because of the reduced complexity of the genome in inbred, purebred dogs as compared to the complex human genome.”

Dogs guide researchers on the path to success

Osteosarcoma, the most common bone tumor in both humans and dogs, is a devastating disease. Only 80% of children with osteosarcoma live more than five years and for dogs the number is lower: only 20% of dogs survive more than two years. The similarities of the disease between humans and dogs makes osteosarcoma an important disease to study. Already studies in dogs have contributed to advances in limb-sparing surgeries and improved chemotherapy protocols in children and dogs. As with lymphoma, veterinary researchers collaborate to study dogs with osteosarcoma because dogs’ more narrow genetic diversity when compared to humans makes identification of genetic abnormalities a bit simpler. In one study, genes associated with cell proliferation, drug resistance, and metastasis were found to be turned on at a higher rate in dogs succumbing to osteosarcoma early, compared to dogs enjoying a longer cancer free life.

Genetic mutations driving tumor proliferation are often similar in human and canine cancers. Another collaborative veterinary research group investigated the similarities between human and canine genes in osteosarcoma.

First, dogs of breeds like Rottweilers and Golden Retrievers that are at high risk for osteosarcoma were studied. Tumor samples were analyzed to identify what genes were turned on in the tumors. This analysis divided the dogs into two groups and, based on the turned on genes, found a marked difference in outcome between the two groups. When the same genes in children with osteosarcoma were analyzed, again two groups with marked differences in outcome were identified. Now researchers can focus on turning off the genes and developing drugs to block the genes’ effects.

For more information about how purebred dog genetics are helping cure disease, read my previous blog, “Fighting Breed Related Diseases.”

Click here for more information about Humphrey!


%d bloggers like this: