National Pet Cancer Awareness Month: Pet Cancer Treatment Options, Part II

November 12, 2014

dog receiving chemotherapyNovember has been designated National Pet Cancer Awareness Month to raise awareness about the causes, prevention and treatment of dogs and cats with this terrible disease. To raise awareness of the possible treatments for pet cancer, this second part of my two-part blog on cancer treatments for pets discusses three additional treatment therapies: chemotherapy, immunotherapy and targeted therapy. Part I focused on surgery and radiation therapy.

Chemotherapy
Although the use of radiation therapy in humans preceded the use of chemotherapy, chemotherapy was more widely used in pet cancers before radiation therapy. Chemotherapy is administered when a biopsy indicates a tumor has spread or might spread, such as in feline breast cancer.

Chemotherapy can also be administered when a tumor is too widespread for either surgical removal or radiation therapy. At the top of the veterinary list of pet cancers treated with chemotherapy is lymphoma.

Veterinary oncologists treat both dogs and cats for lymphoma using a variety of chemotherapy drugs. Most commonly used is the CHOP protocol. CHOP is an acronym representing the first letter of each chemotherapy drug in the protocol and is repurposed from human oncology. Despite the bad reputation chemotherapy has, both cat and dog owners report a good quality of life in their pets receiving chemotherapy.

Immunotherapy
The concept of harnessing the cancer patient’s own immune system to fight cancer is an idea that has been around a long while. The idea came to fruition when a vaccine to treat melanoma in dogs was approved in 2010.

Dogs suffering from melanoma are given four vaccinations over two months and then boostered every six months. This treatment protocol prolonged survival by 300 days or more in dogs receiving the vaccine. In people with lymphoma, treatment using monoclonal antibodies like Rituxan® has dramatically improved patients’ survival time. In a similar vein, AMC oncologists are currently studying a monoclonal antibody against T cell lymphoma and a monoclonal antibody against B cell lymphoma is also available.

On the horizon for the treatment of lymphoma is a new cancer vaccine for a particular type of lymphoma in dogs called large B cell lymphoma.

Targeted Therapy
In 2009, toceranib phosphate, known as Palladia®, became the first targeted therapy approved for use in dogs diagnosed with mast cell tumors.

A second targeted therapy, mastitinib, known as Kinavet®, has conditional approval for the treatment of the same tumor. Targeted therapies exploit a physiologic abnormality in tumor cells, not present in normal cells. Targeted therapies commonly work by turning on or off a cellular process critical to cancer growth and metastasis, halting tumor growth. In the future, expect to see more targeted drugs used in dogs and cats.

Because cancer is diagnosed in over six million pets each year, you may be faced with this diagnosis in your favorite furry friend. But treatment of cancer in pets is possible. You and your pet have more treatment options and more specially trained veterinarians than ever before to help you achieve a good outcome if your pet is diagnosed with cancer. To find a board certified veterinary cancer specialist in your area, visit the American College of Veterinary Internal Medicine website and use their search function.


Get Well Tuxedo Stan: Political Cat Suffers from Renal Lymphoma

January 30, 2013

Tuxedo-Stan-e1359558292930Disclaimer: I am not Stan’s veterinarian and I have not reviewed his medical information nor talked to his doctors. Since lymphoma is the most common tumor of cats, all veterinary oncologists have a good deal of experience in managing this disease.

There are many talented cats who blog. Because I am partial to black and white “tuxedo” cats, Tuxedo Stan from Halifax, Nova Scotia is one of my favorites. Stan believes in taking a political stand. He based his 2012 mayoral campaign platform on the plight of stray cats in Halifax. His politics garnered him endorsements from Ellen DeGeneres and Anderson Cooper.

Early last week Stan announced he was hospitalized at the Atlantic Veterinary College (AVC) on Prince Edward Island for the treatment of the most common type of feline kidney cancer, lymphoma. His most recent tweets indicate he has been released and has returned home.

Lymphoma

Lymphoma is the most common type of cancer seen in cats, approximately one third of all tumors in cats are lymphoma. Stan’s case is a bit unusual since these days most cats with lymphoma suffer from the intestinal form of the disease and, based on his tweets, Stan’s tumor affects his kidneys. During an examination, veterinarians can palpate (feel) large and irregular kidneys. Some, but not all cats with lymphoma of the kidneys have increased values on their kidney blood tests because the tumor cells disrupt normal kidney function. Successful treatment can bring the blood test levels back to normal.

Shaved tummy

In one of his tweets, Stan asked for a sweater because his tummy was cold. He does live in Canada after all. Stan’s abdominal organs were most likely evaluated using abdominal ultrasound. An abdominal x-ray shows the outlines of organs, but an ultrasound lets veterinarians see both the outline and the internal structure of organs as well. Stan’s tummy was cold because we need to shave the fur in order for the ultrasound probe to contact the skin and produce a clear image of the abdominal organs.

Diagnostic test

When oncologists at The Animal Medical Center find a kidney tumor using ultrasound we typically perform a fine needle aspirate to determine the type of kidney tumor, and I suspect Stan had the same or a similar procedure. The radiologist uses the ultrasound images to guide a very thin needle into the tumor. A syringe attached to the needle is used to aspirate (suction) some of the cells out of the tumor. Once the cells are in the needle, the syringe is detached and air is put into the syringe. The syringe and needle are reattached and the air is used to push the cells onto a microscope slide. The slide is stained and evaluated by a specially trained veterinarian called a pathologist. Sometimes these tests are sent to a central laboratory, but because the diagnosis was so rapid, I suspect Stan’s tumor cells were evaluated by a staff pathologist who works at AVC.

Treatment = Chemotherapy

The mainstay of treatment for lymphoma is chemotherapy. At The Animal Medical Center, we typically use a multidrug treatment protocol and rotate drugs on a weekly basis. This protocol attacks tumors using chemotherapy drugs with different mechanisms of action and different toxicity profiles. Administration of chemotherapy drugs to cats requires them to cooperate while the treatment is given intravenously as an outpatient. I hope Stan will give us an update about his ongoing treatments.

Here is more information on signs of cancer in cats.

If you prefer feline social media in 140 characters or less, you might want to use this list to find tweeting cats.

Photo: @TuxedoStan


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.


When Are Two Intestinal Tumors Better Than One?

August 13, 2012

This is the fifth in a series of blogs about pets with intestinal diseases.

Otra is a tortoiseshell cat with an unusual name and an unusual medical condition. The unusual name came about when her new family brought her home. They decided to take a couple of days to pick a suitable name. A temporary name of Otra Gata was chosen because Otra was the second cat in the household and otra gata is Spanish for “other cat.” Otra knew it was the right name for her and immediately responded to it when she was called, so it stuck.

Otra first came to see me nearly two years ago with a diagnosis of lymphoma, a commonly diagnosed malignancy of feline patients.

Otra’s health problems started when she was ten years old, just after her family moved to The Animal Medical Center’s neighborhood. They noticed she appeared thin. Otra first met with an internal medicine specialist who eliminated diseases of the thyroid, kidneys, and diabetes as the cause of her weight loss. An abdominal ultrasound honed in on the problem: an inch-and-a-half-long mass of the small intestine. Ultrasound guidance directed a needle into the mass and obtained enough tumor cells for examination under the microscope. The diagnosis: lymphoma.

Cat chemo

Chemotherapy drugs used to treat lymphoma in cats are the same drugs used to treat lymphoma in humans. Otra began treatment just before Christmas and finished six months later. She felt well, acted normally, and was in complete remission. The chemotherapy treatment dissolved the tumor and it could no longer be identified by ultrasound. For the next year, Otra stopped by for weigh-ins and the occasional examination, but mostly we were happy to see her and to see her doing so well.

Thin again

About 18 months after her initial diagnosis of lymphoma, we noticed her weight dropping and an elevation in her heart rate. Blood tests revealed her thyroid was overactive, an everyday diagnosis in geriatric cats. More ominous was the presence of a small mass in her intestine, a half-inch in diameter. We all feared the lymphoma had returned and repeated the ultrasound-guided aspirate. The results were surprising: no lymphoma cells were seen.

A week or so later, the mass was surgically removed from her intestine. The biopsy did not find lymphoma, but a different type of intestinal tumor, adenocarcinoma.

Strange, but true

Otra’s case is doubly unusual. First, a one-and-a-half year remission from lymphoma is very uncommon in cats. Second, two different intestinal tumors in one cat is also uncommon, although Otra’s two different tumors are the number one and two most common intestinal tumors found in cats. This tidbit of information comes from a 40-year review of over 1,100 feline patients with intestinal cancer. In this recently published study, over 600 cats had a diagnosis of lymphoma and just over half that number had the second most common tumor, intestinal adenocarcinoma.

How can two tumors be better?

If Otra’s lymphoma had relapsed, it would have indicated to me the tumor cells had become very clever and developed pathways to avoid the toxic effects of chemotherapy. Treatment would not have been very successful and I would have not been able to offer a very optimistic prognosis. For intestinal adenocarcinoma, the most important aspect of treatment, surgical removal of the tumor, has already been completed and Otra is nearly normal, except for having to wear the dreaded cone to protect the incision.

Because of her quick recovery and the occurrence of a second treatable tumor, we anticipate many more happy months for her and her family.


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!


Top 5 Health Issues Facing American Pets Today

March 19, 2012

1. Pets are becoming medically underserved

Data shows the pet population in the U.S. is climbing, but visits to veterinarians are declining. On an annual basis in 2007, dogs saw a veterinarian 2.6 times per year and cats only 1.7 times, indicating cats are affected more than dogs. This number has continued to decline in the aftermath of the Great Recession of 2008. Taking your cat or dog to the veterinarian allows early detection and intervention before medical problems like obesity cause serious disease.

2. Obesity in pets, like in humans, is skyrocketing

Veterinarians know pets are getting fatter, but research has shown pet owners are not likely to recognize obesity in their pets, perhaps because they themselves are overweight. In dogs, obesity is linked to an increased body mass index (BMI) in their owners. If you love your pet and want it to live a long, healthy life, keep its weight down. Obese pets have a shorter lifespan and increased risk of cancer, heart disease, respiratory problems, bladder disease, and, like humans, diabetes.

3. Diabetes is increasing in both cats and dogs

Banfield State of Pet Health reports a 32% increase in diabetes in dogs and 16% increase in cats, comparing 2006 to 2010. This is likely tied to the obesity epidemic in pets. Diabetes can be treated in dogs and cats, but it involves someone in the family injecting insulin once or twice daily under the skin and monitoring response to treatment. Preventing diabetes by maintaining an ideal body weight is simply easier for everyone.

4. Cancer: a major illness in both cats and dogs

According to the Morris Animal Foundation, 1 in 4 dogs dies from cancer and cancer is the leading cause of death in dogs over 2 years of age.

In dogs, breed is strongly associated with specific types of cancer. Golden retrievers commonly develop lymphoma, German shepherds a splenic tumor called hemangiosarcoma, and Pugs a skin tumor known as a mast cell tumor. Cats get cancer too, most commonly lymphoma. Annual examinations and blood tests by your family veterinarian will help to detect tumors while they are still easily treatable.

5. Dental disease is on the rise

Reluctant is the descriptor for many pet owners when it comes to dental procedures in their pets. I understand their concern for the required general anesthesia, but I am concerned their reluctance is compromising their pet’s health. Periodontal disease is very prevalent in cats and in one study, all cats had evidence of periodontal disease. Over 10% were severely affected and nearly all had bone loss in the jaw as determined by dental x-rays.

Having periodontal disease may cause collateral damage in other parts of your pet’s body. In dogs, periodontal disease was associated with increases in markers of systemic inflammation and indicators of failing kidney function, and was also associated with endocarditis and heart muscle problems.

For more information on healthcare issues facing American pets today, watch my video interview with Yahoo! Animal Nation.

Photo: iStockphoto
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This may also be found in the Tales from the Pet Clinic blog on WebMD.com.

For over a century, The Animal Medical Center has been a national leader in animal health care, known for its expertise, innovation and success in providing routine, specialty and emergency medical care for companion animals. Thanks in part to the enduring generosity of donors, The AMC is also known for its outstanding teaching, research and compassionate community funds. Please help us to continue these efforts. Send your contribution to: The Animal Medical Center, 510 East 62nd Street, New York, NY 10065. For more information, visit www.amcny.org. To make an appointment, please call 212.838.7053.

 


Pet Oncology Primer

May 9, 2011

The other day in the oncology clinic at The Animal Medical Center, I saw a new patient and managed inadvertently to upset the owner. Her veterinarian diagnosed a “tumor” in her dog and when I asked her how long her pet had “cancer,” she burst into tears. To her, “tumor” implied a benign and curable disease, and “cancer” was a diagnosis that indicated something much worse.

I decided to look up the meanings of these words so I would not upset any new clients in the future as I discussed the conditions of their pets with them. For sources, I used the readily accessible websites, Wikipedia and Dictionary.com. I also got out my dusty copy of Dorland’s Medical Dictionary to be the ultimate source if there was question or conflict between the two websites.

Arrow points to an ulcerated mammary gland carcinoma in a cat.

A tumor is an abnormal growth of cells. The word tumor is derived from the Latin word meaning swelling. Neoplasm is another generic term which, like tumor, does not imply abnormality is benign or malignant. In essence, a lump is a tumor.

Tumors or neoplasms can be benign or malignant. Benign is typically defined by what it is not, rather than what it is. Benign tumors are not invasive and do not disseminate throughout the body (metastasize). Benign tumors typically carry a good prognosis for recovery. Adding the word malignant to the word tumor indicates a growth is invasive into the surrounding tissue or is expected to spread to various sites within the body. Common sites for metastasis are the lung and lymph nodes. Most typically think of malignant as being the modifier for tumor. Malignant may be used as a modifier for a non-cancer medical term meaning a very severe and potentially fatal form of a condition, such as malignant hyperthermia or malignant hypertension.

Arrow points to enlarged lymph nodes from lymphoma in a dog.

In all my sources, cancer was synonymous with malignant. Veterinary oncologists talk about three main types of malignancies in dogs and cats: sarcomas, carcinomas and hematopoietic tumors. The cutaneous mast cell tumor is a common canine example of a sarcoma. Like people, both cats and dogs can develop breast cancer, an example of a carcinoma. Lymphoma is the most common hematopoietic tumor in dogs and cats. In dogs, lymphoma occurs in the lymph nodes and in the cat, in the intestine.

Even though I am an oncologist by training, I never want any pet or person to have cancer. But now I will be clearer in my choice of vocabulary when discussing the nuances of tumors and cancer.

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This may also be found in the “Tales from the Pet Clinic” blog on WebMD.com.

For over a century, The Animal Medical Center has been a national leader in animal health care, known for its expertise, innovation and success in providing routine, specialty and emergency medical care for companion animals. Thanks in part to the enduring generosity of donors, The AMC is also known for its outstanding teaching, research and compassionate community funds. Please help us to continue these efforts. Send your contribution to: The Animal Medical Center, 510 East 62nd Street, New York, NY 10065. For more information, visit http://www.amcny.org. To make an appointment, please call 212.838.7053.


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