Finding and treating oral melanoma, squamous cell carcinoma, and fibrosarcoma in dogs

Finding and Treating Oral Melanoma, Squamous Cell Carcinoma, and Fibrosarcoma in Dogs

Article Featured on Veterinary Medicine
The three malignancies most likely to occur in dogs’ mouths can have devastating local or metastatic effects if not identified and treated quickly. Review how surgery—in conjunction with radiation, chemotherapy, or vaccination—may increase your patients’ survival times.
The oral cavity is a common site for malignant tumors, accounting for 5% to 7% of all canine cancers.1 The most common oral malignancies in dogs are melanoma (30% to 40%), squamous cell carcinoma (17% to 25%), and fibrosarcoma (8% to 25%),1,2 although the frequency of occurrence varies depending on whether tonsillar squamous cell carcinoma is included in the squamous cell carcinoma category. In three studies analyzing 893 tumors either submitted to a laboratory or entered into a database, squamous cell carcinoma was most prevalent (41%), followed by melanoma (37%) and fibrosarcoma (22%).3-5 These studies included tonsillar squamous cell carcinoma (161 cases). If this category was excluded, melanoma would be most prevalent (46%), with squamous cell carcinoma (28%) and fibrosarcoma (26%) making up the remaining tumors.3-5
Less common malignant oral tumors include osteosarcoma, mast cell tumor, hemangiosarcoma, lymphoma, plasma cell tumor, and multilobular tumor of bone (previously called multilobular osteochondrosarcoma). Other disease processes such as benign tumors, gingival hyperplasia, and infectious conditions can occur within the oral cavity and must be considered as differential diagnoses. Benign tumors such as ossifying and fibromatous epulides and the locally aggressive yet nonmetastatic acanthomatous epulis are not discussed in this article.
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Melanoma Tumor in Dogs
Melanoma tumors in dogs, more than most cancers, demand immediate attention. In fact, early recognition of these malignant tumors of melanocytes can lead to more successful attempts at removal and identification of the grade or stage of cancer.
As a group, though, melanomas can be either benign or malignant. The risk of metastasis for benign forms of melanoma is not very high but these can be locally invasive. Malignant melanomas, conversely, can metastasize (spread) to any area of the body especially the lymph nodes and lungs and present very challenging and dangerous prospects for the dog.
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Treating Lymphoma

The Use of Novel Therapeutics to Treat Lymphoma in a Dog

Article by Dr. Patrick Mahaney | Photo: Shutterstock
Cardiff’s last update covered his commencement of chemotherapy (see After Cancer Remission, Using Chemotherapy to Prevent Recurrence), so in this episode I’ll delve into one of the novel aspects of his cancer treatment.
When Cardiff first went through chemotherapy, from January to July 2014, he received a well-established and proven protocol called the University of Wisconson-Madison Canine Lymphoma Protocol (aka CHOP). Of course, I also gave him nutraceuticals (“supplements), herbs, a whole food diet, acupuncture, and other treatments to complement his chemotherapy and help manage side effects.
This time, Cardiff is also getting CHOP, but he’ll also receive a novel treatment that aims to train his immune system to recognize new cancer cells and facilitate their destruction before they form new tumors. It’s called T-cell monoclonal antibody (MAb).
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Complications of Surgery

A Rare But Devastating Complication of Orthopedic Surgery in Dogs

by Dr. Jennifer Coates | Featured on PetMD
Orthopedic surgery is fairly common in dogs. It’s usually needed to repair broken bones or damaged joints (e.g., cranial cruciate ligament tears or severe hip dysplasia), and oftentimes, metal implants (screws, plates, pins, etc.) remain in the dog’s body from that point on.
Dogs usually heal uneventfully after orthopedic surgery involving metal implants, but as is the case with any type of treatment, complications can occur. Most complications arise early on in the healing process (infections, delayed healing, etc.), and are therefore obviously associated with the initial injury and/or surgery. However, one especially devastating complication—cancer—can develop years after surgery involving metal implants.
Metal orthopedic implants have long been associated with an increased risk of cancer at the surgical site in both veterinary and human patients, but the complication is rare enough that it doesn’t get discussed as often as it should. A recent study looked at the characteristics of implant-associated neoplasia (cancer) in dogs and provided a nice review of what we know about the subject. Here are the paper’s highlights.
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What Makes One Skin Mass Cancerous and Another Non-Cancerous?

Article by Dr. Patrick Mahaney | Original Article & Image Featured on PetMD
When an owner thinks of a mass, regardless of the location on the body, cancer should always come to mind. Yet, not all masses that grow inside or on surface of the body are actually cancerous.
I’m well aware of such varying results in my patients, but the reality of being faced with my own dog potentially having cancer besides that which has been cut out his abdomen twice in the past two years is something I just had to face.
Now that you’ve read about Cardiff’s skin mass removals (see What We Do When There Are Tumors On the Inside and On the Outside), you’re likely wondering about his biopsy results. Well, it’s time for the big reveal. Yes, Cardiff has now been diagnosed with more than one type of cancer. Fortunately, the diagnoses show just one more malignant cancer besides his lymphoma, along with many spots of benign cancer.
Before I reveal Cardiff’s results, let’s cover the differences between benign and malignant cancers. First, what exactly is cancer? Cancer occurs when a cell’s genetic material (DNA) becomes irreversibly damaged, which initiates rapid division that does not turn itself off. When enough cancerous cells have multiplied a mass forms. Neoplasia or neoplasm are other terms used for cancer.
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cancer surgery, tumor surgery, skin tumors on dog

What We Do When There Are Tumors On the Inside and On the Outside

Article by Dr. Patrick Mahaney | Featured on PetMD
Before Cardiff became sick with his cancer reoccurrence, a plan to address several superficial skin masses that had gradually developed on the surface of Cardiff’s skin was in the works.
Despite the fact that his teeth appeared quite clean from my nightly brushing endeavors, my plan was to anesthetize him for a dental cleaning and remove the masses for biopsy while he was under. When an abdominal ultrasound revealed another mass-like lesion on a loop of small intestine, this plan was knocked down a few notches on the priority scale.
From their appearance on the skin’s surface, the majority of Cardiff’s masses weren’t clinically concerning. Most were pink, raised, had a lobulated shape, and appeared like a pink piece of cauliflower. I suspected they were sebaceous adenomas, which are benign tumors of oil-producing glands.
Cardiff’s masses had been present for months, but the subtle increases in size and changes in shape along with the dark pigmentation of two of the masses had me somewhat concerned that cancerous cells with malignant characteristics were the underlying causes.
Yet, any mass could have a more sinister cellular makeup than what the outward appearance lends the veterinarian to believe. Therefore, it’s crucial to appropriately monitor all skin masses by measuring their size, describing their physical characteristics, and watching for changes. Additionally, any surgically removed masses or other bodily tissues should always be sent off for biopsy.
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Lung Cancer for Pets

Lung Cancer in Pets is Serious, But Often Treatable

by Dr. Joanne Intile | Featured on PetMD
Lung cancer is the second most common cancer in both men and women (not counting skin cancer). In men, prostate cancer is more common, while in women breast cancer is more common.
Lung cancer accounts for just over 25 percent of all human cancer deaths and is the leading cause of cancer death among both men and women. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined.
Lung cancer is typically diagnosed in older patients, with two-thirds of individuals being age 65 or older. Less than two percent of all cases are found in people younger than 45.
The American Cancer Society’s estimates for lung cancer in the United States for 2015 are:
About 221,200 new cases of lung cancer (115,610 in men and 105,590 in women)
An estimated 158,040 deaths from lung cancer (86,380 in men and 71,660 among women)
Contrary to the disease in people, lung cancer is very rare in dogs and cats. The average age of dogs with primary lung tumors is approximately 11 years and the risk of developing lung cancer rises after the age of 13.
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Targeted Cancer Therapy

In the Battle Against Cancer, ‘Targeted Therapies’ Are Evolving from Human to Animal Medicine

Article by Dr. Joanne Intill | Featured on PetMD
Lymphoma is the most common cancer diagnosed in dogs and cats. It’s also an extremely common cancer in humans. This represents a unique opportunity where people can potentially benefit from treatment options developed for pets, and vice versa.
In people, lymphoma is usually classified as Hodgkin-like (HL) or Non-Hodgkin-like (NHL), with NHL being the most common form. Diffuse large B-cell lymphoma (DLBCL) is the most common form of NHL in people. Though many different forms of lymphoma exist in dogs, the most common form we diagnose in canine patients is similar to the DLBCL seen in humans.
Traditionally, in both people and animals, NHL is treated with chemotherapy using cytotoxic drugs in what is known as the “CHOP” protocol. The chemotherapy drugs in this protocol, though effective, are not specific for cancer cells, and this is the main reason for the adverse side effects seen with treatment.
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What Are the Signs of Cancer Reoccurence in a Dog, and How is it Confirmed?

Article by Dr. Patrick Mahaney | Featured on PetMD | Image Credit: PetMD
Although I strongly suspected Cardiff was having a recurrence of cancer (When Cancer That Was Successfully Treated Reoccurs in a Dog), I still had to take the appropriate diagnostic steps to rule out other disease.
Although he has a history of T-Cell Lymphoma manifesting as a tumor on a loop of small intestine, the fact that Cardiff is showing similar clinical signs doesn’t necessarily mean he has a recurrence of cancer.  Unfortunately for both owners and the veterinarians overseeing their patients’ care, the clinical signs of cancer affecting the intestines are similar to a variety of other ailments of the digestive tract, including:

  • Appetite changes — Anorexia (no appetite) or hyporexia (decreased appetite)
  • Vomit — Active abdominal contraction to expel stomach contents
  • Regurgitation — Passive evacuation of stomach contents (appears similar to vomit)
  • Diarrhea — Some combination of soft or liquid stools, changes in bowel movement patterns, mucus, blood, flatulence, etc.
  • Lethargy — Having less energy for day-to-day activities

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Small Bumps That Appear Harmless May Be a Killer Beneath the Surface

Small Bumps That Appear Harmless May Be a Killer Beneath the Surface

Article by Dr. Jessica Vogelsang | Featured on PetMD
The bump appeared innocuous enough, a little red swelling on this inside of Brody’s ear, no bigger than a tic-tac. He gets little red bumps on occasion, either from scratching at his ears, trauma, or who knows what else dogs like to get into. I’ll keep an eye on it, I said.
I waited a month for it to go away, but it didn’t. It didn’t get bigger, but it didn’t get smaller either. So I was faced with a decision: go through the expense of an aspirate and dragging my dog in for such a minor thing? Or just keep an eye on it?
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