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.

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.

Disease Trumps Species: Winning the War by 2015?
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 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 Golden Retriever'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.

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."

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