A Personal Struggle
Our Golden Oliver led the way when our site came online in 1997. And, his valiant struggle and loss to lymphoma helped us channel our efforts in more healthful and holistic ways. Yet, even with reduced vaccinations, filtered water, a chemically-clean environment, organic foods, and more, we did not escape a fibrosarcoma diagnosis with our Golden Darcy in 2005. Their images, along with other Goldens who have lost such battles, are honored above. Be sure to read veterinarian, Dr. Sophia Yin's article, The Canine in the Coal Mine: Pollutants take their toll on our dogs, a great beginning to understanding the real dangers in our environment.

What is Cancer?
Cancer is an abnormal process within the body that occurs when a normal cell has been damaged and survives in a mutated form. It takes at least two to six spots of damaged DNA (code inside each cell that determines its function) before cancer can occur. Once that damage takes place, the body's defenses will often direct the cell to die or will kill the cell via the immune system. If the damaged cell survives these controls and is able to divide into two cells, and from two cells to four, and so on, then cancer may occur.

This uncontrolled growth of cancer cells can take a solid form, and localize to one part of the body as a visible mass (tumor), or in a bloodborne form, as in leukemia. As cancer continues to quickly grow beyond the control of the rest of the body, it begins to interfere with normal body functions. Sometimes a cancer cell creates a signal that disrupts normal processes distant from the tumor itself, causing changes in blood calcium, sugar, or hormones. The excess or lack of these substances then causes clinical signs.

Some cancers are better than others at metastasis. This is when a cell from the cancer tumor moves into the circulation (via blood or lymph channels) and is carried to another part of the body. If that tumor cell is able to invade the tissues at this new site, again dividing into two cells, and from two into four, and so on, then a metastasis is formed. Treatments are related to a particular cancer’s usual behavior. For a cancer that is aggressive locally (where it is first detected), local treatments such as surgery, radiation therapy, and photodynamic therapy may be used. For tumors with a high likelihood of spreading throughout the body, chemotherapy and possibly immunotherapy (immune system recognizing cancer cells to then destroy them) would be used. Some tumors cause problems both locally and systemically, necessitating a combination of surgery and chemotherapy.

According to The Animal Medical Center's Ann E. Hohenhaus, DVM, DACVIM (Oncology and Internal Medicine), the diagnosis of cancer is not always straightforward, simple, and unequivocal. Dr. Hohenhaus indicates that . . .

	Companion animals with cancer frequently have diseases other than cancer complicating the diagnosis and management of the tumor.
	A complete physical exam and full diagnostic evaluation is necessary to determine the extent of a tumor as well as the extent of the complicating diseases.
	Understanding the sensitivity and specificity of a diagnostic test is critical to accurate interpretation of lab data.
	The presence of a mass does not make a diagnosis of cancer. A biopsy or cytology is necessary to confirm or deny the presence of a neoplastic process.
	If a biopsy result does not make sense in the context of the clinical presentation of the animal, review of the tissue by another pathologist, or re-biopsy is appropriate.
	In companion animals with cancer, the prognosis of the other diseases present impacts the decision-making process regarding surgery, chemotherapy or radiation therapy for the tumor.

An Alarming Rate
One in three persons as well as companion animals are developing cancer, an alarming six million dogs annually diagnosed with a spontaneous, naturally occurring cancer. And, over 45% of dogs older than 10 years of age are dying of the disease, as cancer is the leading cause of death in this age group. Cases continue to increase, a recent study indicating that 63% of Goldens will die of cancer. It is believed that the next breakthrough will be in the form of targeted therapy, such as molecular targeted therapy or gene therapy.

While some tumors are noticeable, others are internal, or cause such subtle signs of illness that diagnosis is delayed. These warning signs can be present in other diseases and don't necessarily mean your dog has cancer, but the presence of any sign should prompt a vet visit ... even if it is just a tiny skin growth or minor behavior change. When in doubt, check it out!

During the exam insist that the tumor be diagnosed rather than settling for a response of "let's watch it and see if it gets any bigger".

If your dog receives a cancer diagnosis, check out this fine introduction, and all of the materials here at the Land of PureGold.

Diagnostic Cancer Screening Advances vs. Buyer Beware
We recently [2012] sought out advice on the myriad of diagnostics being advertised these days. Pet parents are frantic when they learn about the disturbingly high odds that their beloved furry companion may develop cancer. As we are greatly familiar with diagnostic screening for breast, prostate & colon cancers, it seems realistic to wonder what we can be doing for our dogs. Be sure to check out Dr. Modiano's and Dr. Sharkey's advice on this evolving veterinary dilemma. Just click here. 


Disease Trumps Species: Winning the War by 2015? dog
The National Cancer Institute Director issued a challenge to cancer researchers to "eliminate the suffering and death caused by cancer by 2015." Our dogs may be critical to making that a reality. Humans and dogs have been partners for thousands of years, our canine friends quite active in the fight against cancer. In this KQED Quest film, researchers are training dogs to smell cancer in the breath samples of human patients. And, the film details how by studying cancers in dogs, we are discovering new treatments for cancer in human and canine cancer patients (comparative oncology).

While researchers have a greater understanding of cancer biology, their artificially induced cancers in rodents have not afforded them with much success in human trials. Yet, as Dr. David Waters, Co-director of the Purdue Comparative Oncology Program indicates, dogs and humans are the only two species that develop lethal prostate cancers. And, the breast cancer that affects dogs spreads to bones, just as it does in women. Further, osteosarcoma, which is the most frequent bone cancer of dogs, presents in the same way as it does for our teenagers. In fact, under a microscope, cancer cells from a teenager with osteosarcoma are indistinguishable from a any breed dog's bone cancer cells.

According to researcher, Dr. Melissa Paoloni, this sharing of genetic signature has been the genomic proof of principle that the Comparative Oncology Program researchers have been seeking.

In the U.S. each year there are about 6,000 new cases of osteosarcoma in dogs, and about 900 new cases in people. Sadly, nearly half of the cases seen in people are in persons younger than 20. The other issue is this bone cancer's aggressive nature (spreading and metastasizing to other areas). But, there is a new procedure on the horizon that is now being used on afflicted dogs, thus helping scientists determine how it could be utilized in humans. It involves a tiny drill being used to target radiation treatments to the affected cancerous solid bone tumorous area, thus sparing healthy tissue.

In MIT's Technology Review [April 2010], we learn about veterinarian, Dr. Melissa Dauvalt's St. Bernard, Juno, having developed osteosarcoma. Given his huge 165-pound size, amputation was not the best option. Juno was subsequently volunteered for a clinical trial at Texas A&M University. During a two-hour procedure, an electric toothbrush-sized drill was used to inject a radioactive isotope directly into the tumor. The hope is to shrink the tumor without harming any of the surrounding healthy tissue.

The drill was invented by Stan Stearns, Valco Instruments president. In 2008 he had lost his St. Bernard, Gabriel, to osteosarcoma, and had learned during the effort to save Gabriel's life about the poor efficacy of external-beam radiation due to its risk to healthy tissue. But his company had developed tubing that he believed could be the basis of a drill flexible enough to go around corners, burrow into bone, and deliver radiation directly to tumors.

Valco's engineers quickly developed the drill and then partnered with IsoTherapeutics to formulate a radioactive solution that would not travel beyond the tumor. The drill first makes several tiny holes in the bone surrounding the tumor, and next delivers microscopic amounts of the compound into each hole. 

Juno's procedure, performed by Texas A&M veterinarians, involved guidance from a PET/CT scanner. After the team injected a contrast agent that binds to glucose in tumors, the PET/CT showed exactly where to inject the radioisotope.

Sixteen dogs have been treated with this procedure at a handful of veterinary schools and there appears to be an increase in survival. There is even hope that it may work with other bone tumors, especially in women with breast cancer that has metastasized to bone. Juno, who was walking without a limp 10 days after his treatment, will have chemotherapy to attack latent cancer cells. We sure hope there is good news at his 6-month follow-up scan. As is often the case with experimental treatments for our beloved dogs, Juno's mom says there are no regrets, regardless of what his final outcome may be. "We have to find different ways of treating cancer," she says. "I felt this was an opportunity not only to help my dog, but possibly to help people."

Latest Comparative Oncology Findings
Researchers have discovered a genetic cancer link between dogs and humans. Jaime Modiano, V.M.D., Ph.D., University of Minnesota College of Veterinary Medicine and Cancer Center, and Matthew Breen, Ph.D., North Carolina State University's Center for Comparative Medicine and Translational Research, collaborated on this research study. Their findings are published in the journal Chromosome Research, in a special March 2008 edition on comparative cytogenetics and genomics research.

Drs. Modiano and Breen have found that humans and dogs share the same genetic basis for certain types of cancer. Furthermore, the researchers say that because of the way the genomes have evolved, getting cancer may be inevitable for some humans and dogs.

"Many forms of human cancer are associated with specific alterations to the number or structure of chromosomes and the genes they contain," Breen said. "We have developed reagents to show that the same applies to dog cancers, and that the specific genome reorganization which occurs in comparable human and canine cancers shares a common basis." More specifically, Breen and Modiano found that the genetic changes that occur in dogs diagnosed with certain cancers of the blood and bone marrow, including chronic myelogenous leukemia (CML), Burkitt's lymphoma (BL), and chronic lymphocytic leukemia (CLL), are virtually identical to genetic abnormalities in humans diagnosed with the same cancers.

"Interestingly, we found that the same translocation of chromosomes happens in dogs as in humans for the three blood and bone marrow cancers we studied," Modiano said. Breen and Modiano conclude that despite millions of years of divergence, the evolving genomes of dogs and humans seem to have retained the mechanism associated with cancer, and that the conserved changes in the genomes have similar consequences in dogs and humans. The next step for Breen and Modiano is to use grants received from the National Cancer Institute to start pinpointing risk factors for cancer in various breeds of dogs.
 

Spontaneous Mammary Intraepithelial Lesions in Dogs—A Model of Breast Cancer was published November 2007 in Cancer Epidemiology Biomarkers & Prevention. Purdue University research reveals that pre-malignant mammary lesions in dogs and humans display many of the same characteristics, a discovery that could lead to better understanding of breast cancer progression and prevention for both people and companion animals. The similarity between canine and human lesions associated with breast cancer makes dogs an ideal model to study progression of the disease while it is still treatable.

The main form of treatment of breast cancer tumors has been surgical removal. Researchers, Mohammed and Miller, would like to find out if there is a way to identify the lesion early with noninvasive screening, such as ultrasound or magnetic resonance imaging. "Once a lesion is identified, it can be treated with hormonal therapy if it is estrogen receptor (ER)-positive, but for low-risk and ER-negative lesions, we can't do anything but wait and watch to see if it grows into a tumor," Mohammed said. "With a dog model, we could study these lesions and test different prevention modalities before it becomes a cancer."
 

FAIR USE NOTICE
This page contains copyrighted material, the use of which has not always been specifically authorized by the copyright owner. I am making such material available in my efforts to provide background knowledge on areas related to canine cancer. I believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material in this article is distributed without profit for educational purposes.

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