Body tissue is created by a continuous process of division and multiplication of cells. This process helps in the necessary growth and during self-healing and maintenance of healthy cells. The cell division process changes over time, and there comes a stage when it is restricted to the replacement of dead cells. This natural process tends to go awry due to certain factors that disturb the ability of cells to duplicate in a regulated manner. Rapid and unorganized growth of cells leads to formation of benign or malignant tumors.
Benign tumors are lumps of harmless growths that can be conveniently removed by surgery without risk of recurrence. Malignant tumors, on the other hand, are signs of cancer in dogs, which can spread to neighboring as well as distant organs and also threaten life.
Skin cancer, along with cancer of the mammary glands, accounts for the majority of cancers in dogs. Ultraviolet rays play a significant role in causing skin cancer in humans as well as in pets. Feline cancer is common in outdoor cats, and excessive exposure to the sun can harm white or light colored skin more than dark skin.
Skin cancer is basically caused by abnormalities in chromosomes and genes that undergo mutations due to hereditary or environmental factors. Mast cell tumors are the most common form of skin cancer in dogs. Mast cells are large connective tissue cells that contain histamine (amine released by the immune system during allergic reactions), heparin (a polysaccharide that prevents coagulation) and serotonin (a neurotransmitter involved in mood, sleep and memory).
Unlike the symptoms of liver cancer in dogs that manifest as clinical conditions, skin cancer mostly shows visible symptoms like lumps, lesions, ulcers, abrasions and infections on the skin. If the dog is not responding to normal treatment for these lumps, it is recommended that a biopsy or an aspirate be examined as soon as possible.
The veterinarian draws liquid from the tumor by inserting a needle or performs a biopsy to obtain a piece of the tumor for examination. A complete blood count, urinalysis and a serum chemistry panel may also be needed. A chest X-ray may be done to establish whether the cancer has spread to the lungs.
Like treatment of other types of cancer, there are several options for treating skin cancer. This depends on the type of cancer and the stage to which it has advanced.
- Surgery is the first choice for tumors that have not spread so that the entire malignant growth can be removed without affecting the neighboring organs. It is also considered when the tumor is large so that the size can be reduced. This helps in increasing the effectiveness of other treatment options that may be tried after the surgery.
- There are many instances where the whole of the tumor cannot be removed. In such cases, radiation therapy is preferred.
- Where metastasis (spread) has occurred extensively, chemotherapy is used which involves administration of drugs that kill cancer cells.
- Small tumors are treated with cryosurgery which is an application of extreme cold (usually liquid nitrogen) to destroy unwanted tissue and skin cancer.
As skin cancer mostly manifests in visible symptoms, regular and observant grooming normally lets pet owners discover the early signs. Early detection and treatment can save the life of the dog and also a lot of trouble to pet owners as well.