Your dog is 35 times more likely to suffer skin cancer than you are, four times as likely to develop a breast tumor, eight times as likely to suffer bone cancer, and twice as likely to develop leukemia.
(Texas A&M Veterinary School)
Some General Comments
Like many of the treatment pages on this site, I'll start with a few general comments and then try to describe what would happen if you brought your pet into our clinic for treatment...in this case for a mass.
After that, I will soon try to compile as many interesting...or at least informative...articles, comments and links as possible in order to give you a good general background education about cancer and masses in pets.
I hope you aren't reading this page because your pet is in serious trouble. If so, you have my sympathy and prayers.
As always; Please feel welcome to contribute to this page with appropriate material. You'll find my eMail address at the bottom of each page.
Lumps, Bumps, & Cancer in Pets
Unfortunately, cancer is fairly common in pets. The good news is that a lot of the common masses we detect in veterinary medicine that you may think of as cancer are benign.
More good news is that more and more medical advances are being made in the treatment and control of different cancers; so there is hope.
Cutaneous and Sub-cutaneous Lumps, Bumps, and Masses
A lot of dog and cat patients come in for exams because of various lumps and bumps on or under the skin in their pet. In the veterinary business, that's just what we call them; lumps and bumps.
Thankfully, most are not serious, but, of course, that's not always the case.
What To Expect If You Go To The Vet
(your vet may do things differently)
A Good Exam & History: In addition to our normal through exam we will be especially careful to note how long these masses have been there, have they gotten bigger or changed much over time, do they hurt and so forth.
Are the nearby lymph nodes enlarged.
Do they feel fluid filled or solid?
Is the mass mobile or firmly attached? Is it spherical or irregular in shape?
Are they just moles or warts or cysts?
Are they just fatty tumors which are fairly common in middle aged and older dogs?
Are they related to recent injections?
Are they related to skin inflammation or ingrown hairs?
Or are these lumps and bumps possibly cancer? And, if so, metastatic and malnignant? or benign? These are the big questions that we will want to answer.
Often, an experienced veterinarian can assure you with great (but never perfect) accuracy on physical exam alone that a bump is not serious. Other times, it won't be obvious and testing will be appropriate.
If needed, here's what we'll recommend:
Diagnostics:
1. After cleaning and clipping hair if needed, we'll stick a small needle in the lump and see what comes out and look at the fluid if present under the microscope. This simple test will help confirm if the mass is just a fatty tumor, cyst, or abscess. The cost in our hospital is $0-15 depending on whether we use lab stains and fixation or just look at the aspirate directly.
If the lump is a small abscess or cyst, we will often "lance" and express and hopefully cure the problem on the spot. This costs $0-15 depending on how much fun we have. Other times local or general anesthesia and minor surgery is needed to get the job done right and that's more expensive.
2. If no fluid comes out when we stick a needle into the lump or the lump is too big or deep to make a needle stick an appropriate test (an example are the chain of lumps found in breast tissue), or if the fluid is suspicious, then cytology and/or biopsy are appropriate.
Some vets do this in house; I send them to a lab. Since to get a biopsy involves anesthesia (unless very superficial), we often surgically remove the mass at the same time.
3. Radiographs are often appropriate and if your veterinarian has an UltraSound, he or she may want to use it to better define the mass.
4. Blood work is not likely to be needed for the diagnosis of the lump or mass itself, but, of course, would be wise for several reasons: Cancer, if present may be affecting internal organs. Routine blood work will tell us whether or not there is anemia and/or infection present ... both fairly common in conjunction with cancer, and lastly, we like to make sure the internal organs are functioning normally prior to anesthesia which we'll probably need for biopsy or removal of the mass.
Treatment Options
A. We might decide to do nothing except monitor if we think the mass is one of the many typical benign masses we veterinarians see on a regular basis. $0-1,000 depending on how many times you ask me if I'm absolutely sure it's not cancer (just kidding about the cost...but not being sure is the problem with not doing lab work, isn't it?)
B. Simple lancing or removal under local anesthesia if small enough.
C. Anesthesia and Surgical removal. I do this the old fashioned way...with scalpel and scissors...other vets might use a surgical laser or even "freeze" the mass. These methods sometimes have advantages but are generally more expensive.
Cost at our hospital all depends on the size and location of the mass and the difficulty and extent of follow up care (dealing with surgical drains, for example)
D. Post op antibiotics and medications for pain and inflammation if needed
E. Recheck. Remember that masses can be unpredictable and recur.
Deal with the biopsy results if not benign: Choices here are fairly limited;
A. Pray that I removed 100% of the mass (often unrealistic) and it won't come back or isn't already somewhere else in the body.
B. Make the patient comfortable and treat minor secondary problems and maximize the delay of major problems through aggressive nutritional support etc...sometimes there's a long time of quality life prior to eventual deteriation.
C. Referral to an oncologist. Great strides have been made in the treatment and control of some malignant cancers. Cancer therapy can be expensive and have unfortunate side effects and can often be futile, but not always, especially for certain types of cancer...so please give this option some thought.
D. Consider Alternative Medicine. Most of the alternative treatments being heavily promoted to the new age crowd I've tried with very poor results so be careful where you place your faith.
Mammary Cancer in Pets
coming soon...
Prostate and Testicular Cancer in Pets
coming soon...
Warts & Moles
coming soon...
Lymphoma
TEXTBOOK OF VETERINARY INTERNAL MEDICINE
Client Information Series
Susan A. Kraegel
Lymphoma is a cancer of a specific white blood cell called the lymphocyte.
Lymphocytes are found throughout the body in blood and tissues and act to protect the body from infec-tion. Lymphocytes are the major cells found in lymph nodes or "glands." In lymphoma, the cancer cells invade and destroy normal tissues. The most common site for lymphoma is the lymph nodes, but lymphoma cells, like lymphocytes, can grow anywhere in the body. In most dogs and cats with lymphoma, the cancer cells are present in multiple lymph nodes and tissues.
Chemotherapy is the treatment of choice for almost every dog and cat with lymphoma. Chemotherapy is the adminis-tration of drugs by injection or by mouth to kill cancer cells. The chemotherapeutic drug circulates throughout the body. This is important for lymphoma because the cancer cells are in many places at once. Surgery and radiation therapy are less useful in lymphoma because these treatment methods attack cancer cells at only one site.
The goal of chemotherapy for animals with lymphoma is to induce a complete "remission" by killing most of the cancer cells. "Remission" means that all symptoms of the cancer have temporarily disappeared. Animals with Iymphoma that are in complete remission look like normal animals by all tests. They do not have any signs of cancer, and all masses or lumps have disappeared. They eat, drink, and run just as they did before they developed cancer. Some of the cancer cells do survive in an animal in complete remission, but the numbers are too small to detect. Eventually, these few cells will grow and the cancer will become evident again. When this happens the animal is said to be "out of remission." Sometimes a second remission can be achieved with additional chemotherapy. Eventually, the cancer cells will become resistant or insensitive to all drugs and cause the dog or cat to die.
Veterinarians use many different drugs and drug combina-tions called "protocols" to treat lymphoma in dogs and cats. No one knows the "best" treatment, and many protocols give similar results. In general, the longest survival times are reported for protocols that use a combination of drugs and include more expensive drugs.
Although chemotherapy does not cure dogs and cats with Iymphoma, in most it does extend the quantity and quality of life. About 80 to 90 per cent of dogs with lymphoma attain a complete remission with an average survival of 1 year, and 25 per cent of dogs live 2 years. For cats, the remission rate is lower, with about 50 per cent attaining a complete remission, but cats who achieve only partial remission also feel better according to owners. The average sur-vival for cats is 7 to 10 months.
Veterinarians use chemotherapy to give dogs and cats with lymphoma a good quality of life with minimal side effects. Most dogs and cats with lymphoma feel good even though they are receiving chemotherapy. The potential for side effects does exist, however, and varies with the protocol used. The most common side effects include decreased energy, decreased appetite, vomiting, and diarrhea.
Occasionally, more severe side effects occur, and in rare cases an animal receiving chemotherapy will die as a result of treatment. Unfortunately, the only way to know whether an animal is going to have a drug reaction is to give the drug. Some animals never get sick during chemotherapy, but others are very sensitive to the drugs. If your pet has a serious reaction, the drugs or doses your pet receives may be individually adjusted to maintain a good quality of life.
As an owner, you can help your pet with lymphoma by watching the pet closely after each treatment. Chemotherapy will suppress your pet's immune system and make him or her more susceptible to infections. These infections generally arise from bacteria that normally live in the intestinal tract and on the skin, not from the environment. Signs of an infection may include loss of appetite, vomiting, diarrhea, decreased activity, or depression. Phone your veterinarian immediately if your pet appears ill while receiving chemo-therapy. These signs are usually only brief reactions to the drugs, but prompt treatment can often prevent more serious side effects from developing.
FibroSarcomas
coming soon...
Hemangiosarcoma in the Dog
TEXTBOOK OF VETERINARY INTERNAL MEDICINE
Client Information Series
Mona P. Rosenberg
Hemangiosarcoma is an aggressive cancer that arises from blood vessels. The cancer can be found anywhere in the body (because blood vessels occur throughout the body). Hemangiosarcoma is most commonly found in the spleen, liver, and heart.
Prognosis is determined by the location of the disease. Although any breed of dog can develop hemangiosarcoma, certain breeds of dogs appear to be at higher risk, such as the German Shepherd, English Setter, and Golden Retriever. We do not know what triggers the growth of this type of cancer.
Symptoms of hemangiosarcoma are usually determined by the location of the disease. Many dogs with the cancer in an internal organ show signs of intermittent or persistent weakness or even collapse. This is due to a variety of factors. Because the cancer is producing abnormal blood vessels, these vessels tend to be very weak and prone to leaking. Further growth leads to rupture of one of these cancerous vessels, resulting in loss of blood.
As the spleen is the internal organ most commonly affected by this cancer and is an organ that filters the blood, if one of the abnormal blood vessels ruptures, this allows the "spilling" of blood from the spleen into the abdominal cavity. Rapid loss of blood causes weakness or collapse. If only a small amount of blood is lost, the episode of weakness can be transient, as that blood can be reabsorbed into the body. If a large amount of blood is lost, the weakness is so profound that the dog may collapse. This can be an emergency situation. Distention of the belly may also be observed because of the large volume of free blood in the abdominal cavity.
If the cancer is on the heart, this bleeding occurs into the sac that surrounds the heart, resulting in a compromise of the heart's ability to pump blood effectively. This also can cause weakness and potential collapse.
A further problem exists when the cancerous blood vessel ruptures. The release of blood into a body cavity carries with it cancer cells, effectively resulting in bathing of the cavity with cancer cells. This, along with the ease with which cancer cells break off from the abnormal blood vessels and thus gain access to the rest of the body through the bloodstream, results in rapid dissemination of cancer throughout the body. This spread of cancer to distant sites is termed "metastasis." It is this widespread metastasis that makes hemangiosarcoma so "aggressive" and bad. Often the cancer has metastasized before any clinical signs are evident.
When hemangiosarcoma is diagnosed (or suspected), a number of diagnostic tests will be performed to stage your dog's cancer. Staging allows your veterinarian and the veterinary oncologist to educate you further about your dog's disease, allowing you to make informed decisions regarding treatment. A chest x-ray will be performed to evaluate the size of the heart and the lungs and look for metastasis. A complete blood count, chemistry profile, and urinalysis will be obtained to assess your dog's overall health status.
We may perform a coagulation blood panel to evaluate the ability of your dog's body to clot blood. We may also perform an ultrasound examination of the abdomen and! or the heart in search of metastasis. Other tests may be recommended, depending on individual circumstances.
Treatment for hemangiosarcoma involves two different modalities. The first is often surgery to remove the primary tumor. Sometimes, if multiple sites of metastases are found during the diagnostic testing, surgery will be of no benefit. Whenever we are dealing with cancers that have a high potential to metastasize, we use chemotherapy.
Fortunately, chemotherapy in dogs and cats is very different from "chemo" in people.
Because our focus is on quality of life for our pets, this is an important factor; we never want the treatment to be worse than the disease. There are various reasons why chemo is better tolerated in pets, but the most important factor is psychologic. Your dog does not know he has cancer. He also does not know the drugs make people sick, so he does not anticipate that he will get sick. Human cancer patients suffer from a phenomenon called anticipatory vomiting, but dogs do not have this problem. This is not to say that some dogs may not have any side effects caused by the chemo, but in the few dogs that do show side effects, the signs are typically mild and transitory.
Most breeds of dogs do not lose their hair (they have fur, which grows differently from hair). Your veterinarian or cancer specialist will discuss possible side effects with you at greater length.
Unfortunately, hemangiosarcoma is not curable. Dogs with internal organ involvement who are treated with surgery live an average of only 2 months. Dogs who do not have identifiable metastasis at the time of surgery and who are treated with chemotherapy live a median of 6 to 10 months. (Median survival means that 50 per cent of dogs live less than this time and 50 per cent live longer.) Some dogs with demonstrable metastasis may also respond to chemotherapy, providing a prolonged quality of life compared with dogs that are not treated at all. Dogs with this type of cancer located in the subcutaneous tissues (just under the skin) live a median of about 6 months with surgery alone. No studies have been performed on use of chemotherapy for this anatomic location.
Hemangiosarcoma can also occur on the skin of dogs. This appears to be a form of cancer induced by exposure to the sun and carries a much better prognosis than the internal form of the disease. Surgical removal of the skin form, provided it did not arise as a metastasis from the more aggressive form, provides a disease-free interval of about 1.5 years. New lesions can continue to form, however, because of previous or continued sun damage and exposure.
New types of treatments are being investigated continuously in the hope of improving the response rate of dogs with this disease. Again, quality of life is always the main goal, and this can often be achieved by working closely with your veterinary team.
Osteosarcoma
TEXTBOOK OF VETERINARY INTERNAL MEDICINE
Client Information Series
Susan A. Kraegel
Osteosarcoma is the most common type of bone cancer in dogs. This cancer most often affects large, middle-aged dogs weighing more than 40 pounds. Osteosarcoma can occur in any bone (e.g., rib, skull, toe) but the most common sites are the ends of leg bones, especially at the wrist, shoulder, knee, and hip. The causes of osteosarcoma are unknown, but genetics and microscopic injury to the ends of the bone during growth play a role.
Osteosarcoma begins in the bone but spreads to the lungs and other organs early in the course of disease, even before the initial cancer in the bone is detected. This spread of cancer is called metastasis. In 5 per cent of dogs with osteosarcoma, these metastases are visible on a chest x-ray when the dog is first brought in for the bone cancer.
In over 90 per cent of the dogs with osteosarcoma, these metastases are present but are too small to be seen on the initial x-ray. They are termed "micrometastases."
The first sign of ostcosarcoma is generally lameness caused by pain from the cancer. The lameness may come and go and vary in severity from dog to dog. In some dogs the leg may fracture at the cancer site. As the cancer grows, a swelling at the site will also develop, which you may be able to feel or see.
X-rays are the first step in identifying bone cancer. X-rays can only suggest the diagnosis on the basis of the appearance of the bone. X-rays of the chest are also recommended to search for metastases.
Biopsy of the abnormal bone is the only way to diagnose bone cancer absolutely. Side effects of biopsy can include pain, bleeding, and, rarely, fracture of the diseased bone. In 10 to 20 per cent of cases, biopsy may fail to diagnose the cancer, so negative results should be evaluated carefully.
Osteosarcoma is a very aggressive form of cancer in dogs. Oncologists (cancer treatment specialists) have not found a cure. Treatment of both the cancer in the bone and the metastases, however, can give many dogs months to years of good-quality life.
Amputation and chemotherapy are the ideal treatment for dogs with osteosarcoma. The amputation removes the primary cancer and also relieves the bone pain. Most dogs are walking the day after amputation and running soon after. Three-legged dogs have been known to herd cattle and compete in field trials and generally enjoy the same activities as four-legged dogs.
The chemotherapy slows down but does not eliminate the metastases. The chemotherapy currently recommended by most oncologists is usually given once every 3 weeks for four treatments. Most dogs tolerate chemotherapy well and experience only a day or two of mild lethargy or decreased appetite after each treatment. Potentially serious side effects after chemotherapy are uncommon but can include poor to no appetite, vomiting, diarrhea, blood infection, kidney damage, or heart damage. With amputation and chemotherapy, 50 per cent of dogs are alive at 12 months and 15 to 20 per cent are alive at 2 years. Almost all dogs eventually die from osteosarcoma.
Amputation without chemotherapy provides only pain relief. The metastases continue to grow until they cause death. Only fifty per cent of dogs are alive 4 months after amputation alone and 5 to 10 per cent are alive at 1 year.
In rare cases, amputation may not be advised by your veterinarian. Dogs with preexisting disease in other legs or severe obesity may not do well after amputation. One option for these dogs is limb-sparing surgery instead of amputation. This is generally possible only when the cancer is in the front limb in the bone called the radius. With this procedure, the cancerous bone is removed, replaced with bone from a dead dog, and the wrist joint is fused so that it cannot bend. Recovery takes 1 to 2 months and infections are common. Survival times are the same as for amputation. For dogs unable to benefit from surgery at all, radiation therapy may be offered as a treatment to relieve pain. Radiation is given over a 3-week period and reduces but does not eliminate pain in about 30 per cent of dogs. The improvement lasts for about 4 to 5 months in these dogs. This therapy increases the likelihood that a dog will break the limb at the cancer site.
Dogs who do not receive any therapy for osteosarcoma are in pain and have a poor quality of life. This pain continues to progress and, according to people with bone cancer, is severe and uncontrollable. Common painkillers do not work. Euthanasia is generally the only humane choice.
Lipomas (Benign Fatty Masses)
coming soon...
Mast Cell Tumors in Dogs
TEXTBOOK OF VETERINARY INTERNAL MEDICINE
Client Inforniation Series
Mona P. Rosenberg
Mast cell tumors are common on or just under the skin of dogs. Any breed of dog can develop a mast cell tumor (MCT), but certain breeds are predisposed, including Boxers, bulldogs, pugs, Boston terriers, golden retrievers, and cocker spaniels. Mast cells are normal cells within the body that are responsible for responding to allergic reactions. For example, if you are slung by a bee and the area becomes red, hot, and itchy, it does so because mast cells infiltrate into the area, releasing a variety of substances including histamine, causing these symptoms. Other than hereditary factors, we do not know why dogs develop these tumors.
Your veterinarian may have diagnosed this tumor on the basis of a procedure called fine-needle aspiration. This is a minimally invasive technique that involves sticking a needle into the tumor, sucking a few cells out, and smearing the cells on a slide for a pathologist to evaluate under a micro-scope. This procedure is not painful to your dog and allows us to make a diagnosis in most cases. It does not, however, allow us to predict the biologic behavior of ("prognose") MCTs; surgical removal of the tumor followed by the use of a grading system is required. Location of the MCT is also of prognostic significance.
Knowing that we are dealing with an MCT before surgery can be helpful, because MCTs are notorious for sending out long, finger-like projections of cells into the surrounding tissue. This means we must surgically remove a wider margin of "normal" tissue surrounding any visible tumor in an attempt to remove all the microscopic "fingers."
Grade I or well-differentiated MCTs are the least aggressive of the three classes. If we are able to surgically excise the entire tumor (the pathologist will comment that the margins of tissue removed are "clean" or free of cancer cells), the incidence of recurrence is typically small, with 93 per cent of dogs being disease free at 1 year. "Metastasis" or spread of this form of MCT to distant, internal locations is unusual.
Grade II or intermediately differentiated MCTs are more aggressive than their grade I counterparts. An as yet unidentified percentage of dogs with this form of MCT develop metastasis of their cancer to intemal organs, typically to the bone marrow, spleen, or local lymph node. Provided there has been no spread of the cancer, 50 per cent of dogs with completely excised grade II or intermediately differentiated MCTs develop recurrence within 10 months of diagnosis; if no recurrence is detected in this period of time, there is a very good chance that the dog will survive for 5 years free of tumor.
Grade III or poorly differentiated MCTs carry a very poor prognosis, with 97 per cent of dogs succumbing to their cancer by 1 year. This is due to the high rate of metastasis or spread of the cancer to internal organs.
Mast cell tumors in the groin behave similarly to grade III MCTs, regardless of their histologic grade. It is not currently understood, but a high potential for metastasis has been consistently observed. Some oncologists believe that MCTs in the armpits and mucocutaneous junctions (e.g., lip margins, vulva, anus) can be quite malignant as well.
Once a dog is diagnosed with a MCT, several diagnostic tests are recommended. First, a complete blood count, bio-chemical profile, and urinalysis are performed to ensure that your dog exhibits no negative effects of the cancer in his or her system. Sometimes, a blood test called a buffy coat test is performed. This test looks for mast cells circulating through the bloodstream. This test is useful if it is positive, but it is often negative even if the cancer has spread; thus, it is not very sensitive.
The next step is to grade the cancer if this has not yet been done. Again, this can be done only by surgically removing all or part of the tumor. Once the tumor grade is known, a decision regarding further testing and treatment can be made. If the local lymph node is enlarged, it will be aspirated to look for cancer cells. If the MCT has been graded as intermediate or poorly differentiated (grade II or III), aspiration of the bone marrow and the spleen is advised. This is the most sensitive technique for determining whether the cancer has metastasized. Unfortunately, dogs with mast cell cancer in the bone marrow or the spleen have a very poor prognosis; many dogs live only 90 days from the time of diagnosis because of the effects of the cancer cells on the body. Sometimes, even in dogs with advanced disease, treatment can improve both the quality and quantity of life.
Your veterinarian may refer you to a cancer specialist for the testing or further discussion of your options for treatment.
Treatment for dogs with MCTs is dependent on the grade of tumor and results of testing. Dogs with grade I tumors that have been completely excised (removed) are not typically treated with any additional therapy. The "gold standard" of treatment for dogs with grade II MCTs, because of their moderate incidence of local recurrence even with complete surgical excision, is radiation therapy.
We also recommend using radiation therapy to treat grade I and II tumors that cannot be completely excised, provided there is no evidence of metastasis. Eighty-eight per cent of dogs with incompletely excised grade II tumors survive for 5 years without disease when treated with radiation therapy.
For dogs with grade III MCTs, dogs with MCTs in the groin, or dogs that have been diagnosed with systemic spread of their mast cell cancer, drug therapy is often recommended. These drugs include diphenhydramine (Benadryl) and cimetidine (Tagamet) to counteract the effects of histamine on the body and prednisone and other chemotherapy drugs to attempt to kill the cancer cells.
These drugs are usually well tolerated by dogs. Signs of terminal stages of the cancer include lethargy and gastrointestinal signs such as vomiting, diarrhea, and poor appetite.
Our goal for all cancer patients is that their quality of life be excellent; we never want the treatment to be worse than the disease. This goal is often achieved by working as a close team with your veterinarian and often a board-certified cancer specialist.
Solar-Induced Squamous Cell Carcinoma in Cats
TEXTBOOK OF VETERINARY INTERNAL MEDICINE
Client Information Series
Mark M. Smith
Squamous cell carcinoma is a cancerous disease.that most commonly involves skin. Fair-skinned people tend to be predisposed to this type of cancer after chronic, excessive exposure to sunlight.
Likewise, white or light-colored cats are also susceptible to squamous cell carcinoma. Solar-induced squamous cell carcinoma usually occurs in areas with little hair coverage that are chronically exposed to sunlight. The most common area affected in cats is the ear tip.
This disease occurs in older cats and may first become apparent in summer, when sunlight exposure is greatest. The first symptom of this disease that you will notice is reddening of the ear tip. Other early signs of this disease include mild hair loss and flaking of skin on the ear tip. Usually the first impression is that your cat has psoriasis, in which the skin seems scaly and inflamed. If caught early, these clinical signs may be indicative of the precancerous form of the disease known as actinic dermatitis. A small skin biopsy is required to differentiate precancerous actinic dermatitis from squamous cell carcinoma. It is best to perform the biopsy procedure early because the clinical lesions of squamous cell carcinoma are subtle and similar to this form of dermatitis. One or both ears may be affected. If only one ear is diseased, the other should be monitored closely because it may also acquire the disease in the future.
Early, effective treatment of precancerous lesions may prevent the onset of squamous cell carcinoma. Treatment for actinic dermatitis includes sun restriction, especially during times of peak solar intensity; water-resistant sunscreens with sun protection factor (SPF) 15 or greater applied to the ear tips twice daily; topical steroid application; and possibly oral steroid or anti-inflammatory therapy.
The drug etretinate may also be used to alleviate symptoms. The effect of etretinate is to decrease inflammation and skin flaking while normalizing skin cell metabolism. Medical therapy is not effective for lesions that advance to squamous cell carcinoma, underlining the importance of early diagnosis for suspicious le-sions.
Surgical removal of squamous cell carcinoma of the ear tip (partial pinnectomy) is most effective when performed as soon after diagnosis as possible. Early intervention decreases the amount of the ear that must be removed, because the lesion is smaller.
Early surgical removal also decreases the incidence of spread of the cancer to the lymph nodes near the ear. There are different surgical methods that are effective in removing the cancer. With cryosurgery, like frostbite, the ear tip is frozen. The frozen tissue dies and is removed. Although this method may be effective, it is sometimes difficult to control the precise area of tissue freezing. Freezing an inadequate area may lead to recurrence of the cancer, and excessive freezing may result in an unsightly appearance and be associated with excessive scar and deformation of the remaining ear.
Laser surgery is available in veterinary medicine, but the equipment is expensive and may be available only at special referral facilities. Laser surgery provides precise removal of the cancer with minimal, if any, side effects.
Finally, traditional surgical methods may be used to remove the cancer. The procedure is similar to ear cropping in dogs, in which part of the ear is removed with scissors and the skin edges are sutured together. In cats with squamous cell carcinoma of the ear tip, the veterinarian caring for the pet will remove the cancerous ear tip and about one-quarter inch of normal-appearing ear. A small amount of normal-appearing ear is removed to ensure that the entire cancer has been removed.
You should insist that a pathologist evaluate the excised tissue to make sure that the cancer has been completely removed. If the biopsy shows that the cancer has not been completely removed, further surgery should be performed. Incomplete removal of the cancer at the initial surgery is not the fault of your veterinarian. Microscopic evaluation of the tissue after special processing is required to determine whether cancer cells are present in the tissue. The naked eye is not able to make this determination.
Cats tolerate the surgery well, and healing should progress without complication. The healed surgery area will have more hair than the ear tip, which will aid in preventing recurrence of the cancer. Preventive care should be continued after successful surgery.
In summary, prevention of precancerous actinic dermatitis is recommended by limiting the outdoor activity of white or light-colored cats to periods of nonpeak solar intensity. Appropriate sunscreens should be applied to the ear of pre-disposed cats who are outdoors during periods of peak solar intensity. If your cat is diagnosed with actinic dermatitis, it should be treated aggressively in the hope of preventing cancer.
Progression of actinic dermatitis to squamous cell carcinoma requires surgery to remove the cancer. Because of availability and financial considerations, most cats with this form of cancer receive treatment consisting of traditional surgery. The appearance of your cat's ear after surgery will depend on the extent of the disease. The ear may simply appear rounded at the tip or require complete removal. If the entire ear is removed, your cat will still be loved and cute with a striking resemblance to "E.T." of movie fame. Either result is far better than uncontrolled spread of cancer to deeper tissues of the head.
Granulomas
coming soon...
Chemotherapy
TEXTBOOK OF VETERINARY INTERNAL MEDICINE
Client Information Series
Susan A. Kraegel
WHAT IS CHEMOTHERAPY?
The use of a drug or chemical to treat any illness is chemotherapy, but this term commonly refers to the use of drugs in the treatment of cancer. The goal of chemotherapy in companion animals is either to increase the life span or to improve the quality of life for the animal with cancer.
HOW DOES CHEMOTHERAPY WORK?
Cancer can be defined as a rapid, uncontrolled growth of cells. Anticancer drugs work by blocking cell growth and division. Different drugs interfere with different steps in these processes. In many cases, a combination of drugs is the most effective way to kill the cancer cells.
HOW IS CHEMOTHERAPY GIVEN?
Most anticancer drugs are given by mouth or by injection. The route chosen depends on the type of drug and the type of cancer.
HOW LONG WILL MY PET RECEIVE CHEMOTHERAPY?
The length of time and frequency of drug administration depend on the kind of cancer being treated and how well the therapy is tolerated by the patient. Treatment may be given daily, weekly, or monthly.
AM I AT RISK OF EXPOSURE TO THESE DRUGS?
Yes. Most anticancer drugs are very potent and must be handled with care. Some are "carcinogens" and can cause cancer with prolonged exposure. With orally administered drugs, it is important that the pills or capsules are kept out of reach of children in childproof containers. When handling these drugs, the owner should wear latex or polyvinyl gloves to avoid unnecessary exposure. With oral and injectable drugs, the urine and feces of the animal may be contaminated with active drug compounds for several days after administration. Always avoid contact with the urine and feces of animals receiving chemotherapy. Wear latex or polyvinyl gloves to clean up accidents or the litter box. Rinse exposed surfaces well.
WILL MY PET EXPERIENCE SIDE EFFECTS?
Maybe. Veterinarians try to choose drug doses and combi-nations that cause the fewest side effects. Ideally, the animal receiving chemotherapy does not even realize that he or she is ill. The drugs used in chemotherapy, however, are ex-tremely potent and side effects can occur. The potential for side effects must be balanced against the benefits of the chemotherapy and the side effects of the cancer if left untreated. Choosing chemotherapy for your pet is an individ-ual decision.
WHAT KINDS OF SIDE EFFECTS OCCUR?
Side effects arise because the normal cells in the body are also exposed to the anticancer drug. The most sensitive normal cells are found in the blood, gastrointestinal tract, skin, and reproductive system. Consequently, potential side effects include infection, bleeding, decreased appetite, vomiting, diarrhea, thin haircoat or skin color changes, and sterility. Rare side effects associated with specific drugs include bladder discomfort, kidney damage, and heart fail-ure. The most serious side effect is overwhelming infection leading to death.
WHAT ARE THE MOST COMMON SIDE EFFECTS?
The most common side effect reported by owners is that the pet seems to be "off" for a day or two. This might mean that the pet has slightly less energy or seems less excited than normal about eating. Less commonly, the pet may skip a meal or two, have one episode of vomiting or diarrhea, or seem lethargic. Unfortunately, there is no way to predict which pet will develop the most serious reactions. The animal receiving chemotherapy needs to be watched closely and taken to his or her veterinarian at the first sign of illness.
