Dr. Val at work with his assistant and Kim's dogs. Photo by Kim Aranha

A couple of weeks ago I told my friend Dr. Val Grant, who is Veterinary Surgeon and currently practices medicine at the Palmdale Veterinary Clinic in Nassau, Bahamas, that I wanted to do a comprehensive article on some of the medical issues facing our small animal pets. In the light of all the animal cancer issues we have heard of lately, culminating quite recently with the untimely passing of "Amigo" who was the poster dog for the Spay and Neuter Program of the Grand Bahama Humane Society. This sad loss was reported in the press. I decided to start off with an article on cancer.

I emailed questions to Dr. Grant, fully expecting to have to paraphrase some very medical data. Not at all, Dr. Grant emailed me the most complete and comprehensive answers I could have wished for. I have decided to publish his answers verbatim, and wish to publicly thank Dr. Grant for taking time out of his extremely busy schedule to enlighten us and help us care for our pets better:

Dr. Valentino Gant :: “I would like to say to ALL Grand Bahamians how much I thoroughly enjoyed caring for their animals (for over 12 years) and treasure the many friendships forged during my tenure there” 

Amigo (a very typical Bahamian Potcake) was very dear to me as I was the Veterinarian who tended to him and aided in his rehabilitation after he was found by Frances-Singer Hayward over 7 years ago. Unfortunately he succumbed to cancer, a very deadly disease whose incidence in dogs at times surpasses that of humans and is about half the rate in cats.   

Almost, (if not) everyone reading this article knows of a relative or friend who has had cancer.  At Palmdale Veterinary Clinic where I presently practice, the incidences and detection of cases of cancer is increasing.  A large part of this is due to the fact that pets are living longer due to improvements in owner and (standards of) veterinary care. 

  There are many questions concerning cancer such as:

  1) What is Cancer?

Cancer is an uncontrolled growth of abnormal cells on or within the body.  Cancer may be benign or malignant.  It may be localized or may invade adjacent tissues and spread (metastasize)  throughout the body.

Benign tumors have many normal growth characteristics.  Their cells multiply but they do not " spread " or invade other organs. They may, however, by virtue of their size, compress body organs or tissues and thus, can interfere with the proper functioning of these organs.  One of the most common benign tumors that I see quite frequently in practice is a Lipoma [which is a benign collection of fatty (adipose) tissue.

Malignant tumors often have very rapid, irregular growth characteristics.  They invade normal local tissues as well as metastasize (spread) systemically to the organs like the lungs, liver, spleen etc.   

 
2) In what animal do we see the most incidences of cancer?

  The highest rate of cancer is seen dogs and over 45% of them will die from cancer after attaining the age of 10 years.  It should also be noted however that ALL species of animals develop cancer and the the disease can occur anywhere in the body. 

3) What are the common symptoms of cancer?

Some are:  A) Abnormal swellings that persist or continue to grow

                  B) Sores that do not heal

                   C) Unexplained weight loss

                  D) Loss of appetite....Anorexia

                  E) Bleeding or discharge from a body orifice

                  F).Difficulty breathing

                  G) Difficulty swallowing

     
4) What are the some of the most common cancers of dogs and cats and how do they manifest themselves?

 
A common tumor that affects both dogs and cats is a tumor of the lymph nodes. It is called a Lymphoma and is characterized by swelling of the lymph nodes throughout the body.  

Tumors of skin and subcutaneous tissues are the most common tumors in dogs and they account for one third of all the tumors in dogs.   

There are also cancers of the respiratory system. Quite recently a very dear friend of mine lost her 2 Bernese Mountain Dogs to Malignant Histiocytosis a cancer which for the most part has its primary focus within the tissues of the lungs.   

There is also breast cancer whose incidence is influenced by hormones. It is now well established that dogs spayed before their first heat have a greatly reduced risk of developing breast cancer. The risk of developing tumors of the breast   (approximately 50% of which are malignant,) rises from nearly 0% in dogs spayed prior to their first heat to 26% for dogs that are spayed after their second heat cycle. THINK ABOUT IT!!  THIS IS ANOTHER REASON WHY IT IS IMPORTANT TO SPAY OUR PETS. 

In General there are cancers of literally every system of the body.

 
5) What causes cancer?

Cancer is now considered a Genetic Disease and the evidence for its genetic origin is now clearly elucidated, what with the advances in molecular biology and animal genome projects. It is thought that many genes contribute to (rather than "cause”) the origin and progression of cancer.

There is however a rather complex interaction between cells and their exposure to certain Chemical, Physical and Hormonal agents. Certain chemicals called Carcinogens increase the occurrence of cancer.  Physical factors such as Sunlight and the ultraviolet radiation produced results in cases of skin cancer, especially in animals with light skin pigmentation. Chronic inflammation of tissues may lead to mutations that result in cancer.

Also as I mentioned above, there are hormones (like estrogen, progesterone and testosterone) which have a direct role to play in the development of certain cancers like breast cancers and cancers of the anal region. There are also Viruses which cause cancers like Papillomaviruses. They cause wart-like lesions to develop in places like the mouth (oral cavity). 

There are also viruses which cause Leukemia in cats and there are quite high incidences in the Bahamas . Also there are viruses which are spread sexually between dogs and result in tumors of the penile and vaginal regions. Many of the Potcakes seen around town have these large masses literally “hanging “from these regions. 

The clinical signs of prostatic cancer are similar to those of other prostatic diseases.  Pain and fever may be present.  If the cancer infiltrates the urethra, there will be difficulty to urinate and sometimes there is total blockage of the urethra.

Most times by the time Prostatic adenocarcinoma is diagnosed there is metastasis to other organs in over 80% of dogs.  The most common sites for spread are the lumbar vertebrae, the pelvis and the regional lymph nodes.

There is no curative treatment!!  There is a high incidence of incontinence after partial or total removal of the prostate or after radiation therapy.

       
6) How is Cancer Detected and Diagnosed?

  Cancer is detected by a number of  methods namely:

a) Visually and physically palpating (feeling) the mass (EXTERNAL METHODS)

b) Utilizing technology that enables us to seen INTERNALLY like  X-rays, Ultrasonoagraphy, Computed Tomography, Magnetic Resonance Imaging (M.R.I.) and Scintigraphy ( a process of administering a radioactive chemical to highlight an area of interest) 

Cancer is DIAGNOSED by obtaining samples of cells and tissues via many different collection methods......A BIOPSY BEING ONE OF THE MOST IMPORTANT MEANS.  The samples are then submitted to a Pathologist who then determines whether they are cancerous or non-cancerous.

  7) How is Cancer treated?

 There are many different treatment modalities.  There is Chemotherapy, Radiation therapy, Immunotherapy and Surgery. In the Bahamas the 2 most common ways of treating/resolving cancer are Surgery and Chemotherapy. There are some cancers which can be fully resolved with chemotherapy like the aforementioned Venereal tumors of dogs which are called Transmissible Venereal Tumors (T.V.T).It is truly amazing to watch the tumors shrink until they are no longer present when we treat these particular cases. IF ONLY THIS COULD BE THE CASE FOR ALL CANCERS!!

Veterinarians in the Bahamas are now utilizing more chemotherapeutic protocols.  Some of these medicines are very expensive and the doctor has to weigh the risk versus the benefit to the patient.

Radiation therapy is not yet available to the animals of the Bahamas and would have to be done in another country that offers this modality of treatment.

There are at times side effects to both Chemo and Radiation therapy.  Symptoms such as vomiting, diarrhea, nausea, lethargy and lack of appetite can occur.

The relative success of treatment depends upon the type and extent of the cancer as well as the general health of the patient.  

As we continue to do "battle" so to speak against this most debilitating and deadly disease it is my hope that more discoveries will be made which will lead to increases in the cure and remission rates.

Sincerely,   

Dr.Valentino Grant ( D.V.M)