Entries Tagged 'Dog Cancer' ↓

Despite a good prognosis for some types of cancer, due to the fatality and toxicity of the medication associated with it, pet owners are often confronted with a dilemma whether to go for a treatment or not. Most of the times, cancer in dogs occurs in old age making dogs more vulnerable to the side effects of conventional treatment. Surgery has a limited scope in as far as it can only excise parts of the tumor.

There is a dire need for exploring new areas of cancer treatment. Despite significant developments in this field, a lot more needs to be done to develop new strategies and drugs that target only cancerous cells and spare the normal cells.

The development of any new treatment needs to be done keeping in mind that any medication should cure the disease with a minimum of side effects. To achieve this goal the therapy has to target and destroy only the cancer cells while it allows the normal healthy cells to live.

Let us try to understand how radiation and chemotherapy work to kill malignant cells. These therapies make use of the fact that malignant tumors have cells that grow rapidly by division whereas the normal cells are mostly in a resting stage. Chemotherapy attempts to intervene at the DNA function of cells to divide and multiply thus leaving the normal cells alone.

There is an exception to this rule because even some normal cells like those in bone marrow and the GI lining naturally continue to divide and replace dead cells all the time. Moreover, sometimes normal cells start dividing and replacing after the treatment is given. This leaves a very small margin of error.

Another limitation of conventional drugs is the field of recurrence. There is a great amount of heterogeneity within the cells of a single tumor. As the tumor increases in size, some of the cells get lesser blood supply causing them to divide at a reduced pace compared to others in the same tumor. This results in making some cells resistant to drugs and they can survive even after the patient is cured of the disease. These cancerous cells remain dormant for a time and lead to recurrence of cancer at a later stage.

On the other hand, surgery has a different set of limitations. Pet cancer, including canine and feline cancer has the uncanny property of surfacing when it has already metastasized to neighboring, distant and even vital organs. This either rules out surgery or at best results in partial excision of a tumor. And therefore, chemotherapy and radiation become necessary. It is only in rare cases like liver cancer where pet owners can notice the condition early enough for treatment since the symptoms of liver cancer in dogs are quite apparent at an early stage.

Total excision is only possible in cases of a benign tumor, which is, in most cases, harmless. On the other hand, any increase in dosage of chemotherapeutic drugs or time of radiation exposure has an accompanied and corresponding risk of increase in toxicity. Pet owners need to take an educated decision based on the general health of the dog and risks involved. In fact owners have to strike a balance between compassion, quality of life after treatment and benefits likely to be derived from treatment.

Cancer is actually an uncontrolled growth of cells resulting from an accumulation of changes in the structure of the genes that control cell division and multiplication. Melanoma is one of the several malignant neoplasms, usually of the skin. The affected cell is mostly melanocytes, a cell in the basal layer of the epidermis that produces melanin under the control of the melanocyte-stimulating hormone. Benign and malignant skin tumors are a common form of canine and feline cancer.

Melanoma cancer in dogs occurs commonly in dark skinned animals, usually in areas under haired skin, as small, dark brown to black lumps. In certain cases they may appear as large flat wrinkled masses. Other areas where melanomas can also appear include mouth, digits and behind the eye. A swelling or increase in size of lymph nodes is the first clinical sign of a malignant melanoma. Although the pigment called melanin is the distinctive characteristic of such tumors, some melanomas may not display a darkly colored pigment.

Malignancy is established with the aid of a microscopic examination. For this purpose a small piece of the tumor is cut off and evaluated. The pathologist then grades the melanoma according to how rapidly the cells are proliferating. This gives an estimate of the likelihood of metastasis.

The best treatment of melanoma is a total excision through surgery. To be on the safer side, the surgeon may remove some of the neighboring tissue as well. If the tumor is confined to a particular area this amounts to a full cure. The excised sample is again sent for histological examination to ascertain whether the entire tumor has been removed or not.

Melanomas can also spread to distant organs in the body. Complete remission in such cases is rare and it affects the long term survival of the dog to a great extent. Once the tumor has metastasized, cancer can start presenting itself as varied symptoms like the symptoms of liver cancer in dogs.

To the relief of dog owners, all moles in the skin are not malignant. It is normal for a dog or a cat to have dark pigmented areas of skin, particularly in the tongue, gum and eyelid tissue. As a general rule small skin tumors tend to be benign and the ones in the mouth toes, fingers or eyes are mostly malignant. Benign melanomas are seen as dark masses up to two inches in diameter. Unless the mole or a lump starts increasing in size, or elevates above the surface of the skin or bleeds, there is no need to worry. Such a condition necessitates an examination of the lump that you may see on the surface of your dog’s skin.

The spleen in the body is the storehouse of blood. It also functions as an organ for destroying old red blood cells and holding blood for emergencies. It is an important part of the body’s immune system. Located just below the stomach, in emergencies such as a hemorrhage, it springs into action to provide blood for replenishing the loss. Even though life can be normal without a spleen, its absence, however, predisposes infections.

The spleen constitutes of a red soft surface containing two different types of pulp - white and red. While the red pulp functions as a mechanical filter removing unwanted substances from the blood, the white pulp helps to fight infections.

A growth in the spleen signifies abnormality and the presence of cancer cells needs to be investigated. A growth leading from the red pulp is usually a rare malignant neoplasm characterized by rapidly proliferating anaplastic cells known as hemagiosarcoma. It is derived from blood vessels lining blood-filled spaces. Growths arising from the white pulp are either mast cell tumors or a lymposarcoma, which is the more common type of feline cancer rather than canine cancer. Two third of all spleen tumors signify cancer in dogs . Again about two third of all malignancy in spleen arises from the red pulp causing hemagiosarcoma.

Some splenic tumors can look exceptionally large in radiographs but may actually turn out to be benign. Even benign tumors can be very dangerous as they can rupture any moment without notice, often resulting in instant death due to excessive bleeding. A ruptured tumor, thus, necessitates immediate attention, a quick diagnosis, surgery and intensive care.

Clinical signs of a splenic tumor can be as confusing as the symptoms of liver cancer in dogs. Your dog may show pale gums and a distended stomach or a hard mass may be felt in the abdomen. Some general symptoms like weakness and loss of appetite also indicate a splenic tumor. One of the prominent signs is the change in color of the urine due to breakdown of red blood cells and when hemoglobin starts getting excreted. The urine may develop a dark brown color.

Prognosis of a benign tumor is good and surgery is an effective treatment. In some cases there are only torsions of the spleen, which too have a good prognosis. If malignancy is not suspected the dog may require to be stabilized with intravenous fluids and a blood transfusion.

Malignancy, however, requires the spleen to be removed. However, after surgery there may be complications like infection, death due to anesthesia, an abnormal rate of muscle contractions in the heart that may even cause an instant death.

Splenic tumors often tend to metastasize in microscopic masses to the lungs, liver, heart and other organs of the body. Even a small malignant tumor in the spleen cannot be felt on palpating the abdomen. The only way a splenic tumor can be detected in its early stage is through regular check ups.