Lymphoma is the most common cancer we treat. It is analogous to non-Hodgkin’s lymphoma in people. Similar to that disease, it is a systemic cancer, meaning we cannot just “go in” and remove the tumor. This is a disease of the lymphatic system- there are lymphatic vessels in every organ and there are lymph nodes on the inside as well as on the outside of the body.

Being it is a systemic disease, the treatment needed is systemic—chemotherapy. When you hear this term, you think of what happens to people who get chemotherapy. But animals handle chemotherapy much better than people—this is because we use a lower dose of chemotherapy and because dogs and cats seem to tolerate the drugs better than people. Most of the pets that we treat, 70-80%, have either no or minimal side effects.

 

Chemotherapy is administered intravenously weekly for 6-8 weeks then every other week, usually for a year in dogs and two years in cats. We use various drugs in a cyclic protocol. Our trained oncology technicians administer the chemotherapy. We try to perform all chemotherapy as outpatient procedures with most administrations taking 5-30 minutes. The side effects of chemotherapy, which are usually mild, can include: vomiting, diarrhea, loss of appetite and loss of energy level. If these side effects do occur and they are mild, there is no need to worry. If the side effects

are more than mild or if you are unsure if they are mild or not, we would always rather you call.

Our doctors will try to answer all questions you have regarding your pet’s cancer and the recommended therapy, but if you would like more information the links below are helpful and contain reliable information

 

Melanoma Tumor In A Dog

Melanoma tumors in dogs, more than most cancers, demand immediate attention.  As a group, melanomas can be either benign or malignant.  Early recognition of melanomas can lead to more successful attempts at removal and identification of the grade or stage of cancer.  The risk of metastasis for benign forms of melanoma is not very high but these can be locally invasive.  Malignant melanomas can metastasize (spread) to any area of the body especially the lymph nodes and lungs and present very challenging and dangerous prospects for the dog.  Cats seem much less susceptible to melanoma tumors than dogs.

 

 

BENIGN MELANOMAS...
Benign cutaneous melanomas of dogs are usually seen as round, firm, raised, darkly pigmented masses from one-quarter to 2 inches in diameter.  They occur most often on the head, digits or back.

 

MALIGNANT MELANOMAS...
In the dog, presence of malignant melanoma may be first discovered in the lungs where diffuse pulmonary infiltration of tumors will be displayed throughout the lung tissue on a radiograph (x-ray).  Lymph node swelling or enlargement may be a clinical sign of malignant spread of a melanoma.  Some melanomas do not display the characteristic darkly pigmented color of most melanomas.  The pigment called melanin is a hallmark of these tumors and usually is present in large amounts in melanomas.

DIAGNOSIS...
A definitive diagnosis is made via microscopic analysis (histopathology evaluation by a Specialist in Veterinary Pathology) of a small section of the growth.  This is called a "biopsy" of the tumor.  The examining pathologist usually will grade the specimen according to how actively the cells are replicating.  This gives an approximation of how likely the growth is to invade and spread.  If an entire growth is removed, the pathologist can report on the tissue's grade as well as any evidence that parts of the tumor may not have been thoroughly excised by the surgeon.

TREATMENT...
Treatment of melanomas is best provided by surgical excision of the tumor and nearby surrounding tissue.  Localized tumors may be completely removed and the patient cured.  However, if a malignant melanoma has had the opportunity to spread to distant areas of the body, long term survival of the dog is not likely.  Chemotherapy has been performed with marginal success; complete remissions of metastatic melanoma cases are rare.  Fortunately most cutaneous (skin) melanomas are benign, but individual growths need to be evaluated as unique and unpredictable since any given melanoma may become malignant.

 

Hemangiosarcoma

Hemangiosarcomas are a form of cancer which originates in the endothelium, which is the lining of blood vessels and spleen. As might be expected of a tumor arising in the blood system they are highly malignant and can be found almost anywhere in the body since blood vessels are necessary in almost all body tissues. There is a strong predilection for the spleen, pericardium and heart. These tumors are most common in middle aged or older dogs which are medium sized or larger but can occur in any breed. German shepherds are reported to be more susceptible to this tumor than most dog breeds. In our practice golden retrievers also seem to have a higher than normal incidence.

Because these tumors arise in internal organs there is often little warning that they are present prior to time they cause severe clinical signs of disease. A common estimate of the average time from discovery of the tumor until death occurs in affected dogs is six to eight weeks but death occurs more rapidly than this in a number of cases.

Visible bleeding, usually in the form of nosebleeds, and signs associated with blood loss, such as tiring easily, episodes of unexplained weakness, pale color to the mucous membranes of the mouth and eyes, increased respiratory rates, abdominal swelling and depression are the most common presenting signs for patients with hemangiosarcoma. A few dogs just suddenly die with no clinical signs having been noted by their families prior to death.  Bleeding disorders associated with hemangiosarcoma are sometimes confused with immune mediated hemolytic anemia (IMHA) because the type of anemia caused by the two conditions is very similar and early clinical signs are often very similar, as well.  Hemangiosarcomas can cause very large tumors, sometimes as large as ten or more pounds, when they affect the spleen.

 

In most instances tumors of this size in this location are found on physical exam.  In other cases the tumor affects the heart and is hard to find on a physical exam and even easy to miss or X-rays. Sometimes there are hundreds of small tumors spread throughout the body and surgical exploration or an autopsy are the only ways to identify the problem.

The blood disorder that most commonly accompanies the presence of hemangiosarcoma tumors is disseminated intravascular coagulation (DIC). This is blood clotting that is occurring inappropriately inside the blood vessels.  It uses up all of the blood clotting elements rapidly and dogs with this condition usually have platelet deficiencies, increased blood clotting times, decrease in fibrin content in the blood and an increase in fibrin degradation products (FDPs).  This is probably the cause of death in most dogs affected with hemangiosarcoma.

Diagnosis of hemangiosarcoma can be accomplished in a number of ways.Identification of a tumor in the spleen or heart raises a high degree of suspicion for this tumor. Abdominal swelling is also highly suggestive in an older large breed dog. If fluid is aspirated from the abdomen and it looks like blood it is even more suggestive of hemangiosarcoma. If  blood is drawn and will not clot when left in the syringe it is another sign  that a dog may have this tumor. In some cases careful evaluation of the type of bleeding  disorder present is necessary to raise the suspicion of hemangiosarcoma.

If a tumor is identified when it is small it may be possible to remove the spleen if the tumor is there or even to remove tumors found near the heart and prolong the pet's life. Most of the time this will not make much difference, though. These are highly malignant tumors and most have spread by the time they can be identified. To the best of my knowledge there is not a very successful hemotherapeutic or radiation protocol for this cancer at this time but dogs treated with chemotherapeutic agents do live a little longer than dogs that do not receive this treatment.

 

Treatment for the bleeding disorders and aggressive supportive care also prolong the life of patients with hemangiosarcoma. If treatment for IMHA or immune mediated thrombocytopenia (ITP) are instituted due to confusion over the underlying cause of clinical signs early in the diagnostic process there is not likely to be any harm to the dog.

Due to the tendency to look for an inciting agent in IMHA and ITP it is a good idea to consider an autopsy exam if a dog dies before a definite diagnosis of any of these conditions can be made.  Finding hemangiosarcoma saves a lot of agonizing over possible causes of the death of a friend. There are no known predisposing factors other than size and breed that I am aware of for hemangiosarcoma

 

Fibrosarcoma
The general description of a Fibrosarcoma is a type of soft tissue sarcoma in the fibrous tissue, which holds bones, muscles, and other organs in place.

A FIBROSARCOMA is a malignant (invasive) cancer originating from fibrous connective tissue.  Fibrosarcomas may spread (metastasize) to other areas of the body.

 

Mast Cell Tumor

Quick Facts:

• 20-25% of all skin/subcutaneous tumors in dogs are mast cell tumors (MCT)
• 10-15% of canine MCT are clinically indistinguishable from subcutaneous lipomas
• Definitive diagnosis of MCT cannot be made without cytologic or histologic evaluation of the lesion
• Behavior of individual MCTs is difficult to predict but should always be considered aggressive until proven otherwise
• 20% of dogs with MCT will have multiple primary tumors in their lifetime
• Aggressive surgical resection remains the cornerstone of treatment
  

Background:
Mast cell tumors are one of the most common skin tumors of the dog. There are three grades of mast cell tumor: grade I, II and III. Grading involves a pathologist looking at a tumor underneath a microscope and analyzing how abnormal the cells look and how invasive they are into the surrounding tissue--usually, the higher the grade, the more aggressive the tumor.

We also stage animals that have mast cell tumors. Staging involves determining where the tumor is in the dog and where it is not. The tests we perform to determine the stage are: chest x-rays, abdominal ultrasound, lymph node aspirate and cytology, and a bone marrow evaluation.

Clinical Appearance:
Mast cell tumors can look like anything; they are most commonly reddish, raised masses on the skin. However, they can look and feel like fatty tumors as well. These tumors commonly cause the pet to feel “itchy” in the general area of the mass. This occurs due to the presence of chemicals, including histamine, in the granules of the mast cell tumor. Histamine is the chemical most responsible for the redness, itchiness and swelling, characteristics typical of an allergic response in people.

 

Diagnosis:
The diagnosis of mast cell tumor requires either cytology or histology. Cytology of a mass that demonstrates cells with bluish granules confirms the diagnosis of mast cell tumor. The grading of the tumor, however, requires a biopsy.

Treatment:
Surgical removal is the treatment of choice for most mast cell tumors. Grade I tumors are usually small and superficial and can be effectively cured with surgical removal. Small grade II tumors are also usually cured with complete surgical removal. It is when grade II or III tumors cannot be completely removed or when they have already spread to other parts of the body, do we need to use additional or adjuvant therapy. Radiation therapy and chemotherapy are often used in aggressive grade II or grade III tumors. Radiation therapy is useful in large (>4cm) grade II tumors that have been surgically removed, as it is unlikely that all malignant cells have been removed, or with grade II mast cell tumors that cannot be completely resected. Radiation therapy is beneficial in grade III mast cell tumors as well. Chemotherapy is beneficial to dogs with both grade II and grade III mast cell tumors when there is spread of the disease to distant parts of the body or to prevent tumors that have a high chance of metastasizing from spreading.

Useful links for more information:
http://www.vrcc.com/disease_mc_tumors.shtml

What are the clinical features?
Mast cell tumors in dogs occur primarily as either a skin or subcutaneous mass. It is important to remember that mast cell tumors are extremely variable in their clinical presentation. They can resemble any other type of skin or subcutaneous tumor, both benign (ie. lipoma) and malignant. Most canine MCT are solitary although multiple primary tumors develop in 20% of patients. Approximately 50% of canine MCT are located on the trunk and perineum, 40% on the extremities and 10% on the head and neck.Regional lymphadenopathy may occur when high grade 2 or grade 3 mast cell tumors metastasize to draining lymph nodes. Hepatomegaly and splenomegaly are features of advanced stage, metastatic MCT. Malignant mast cells may be detected in the bone marrow of dogs with advanced stage disease.

 

Cytology vs. histopathology?
The diagnosis of MCT is often made simply with cytologic evaluation of a fine needle aspirate of the mass. Cytology reveals round cells, with basophilic cytoplasmic granules, that do not form sheets or clumps. In cases where the malignant mast cells are agranular, the presence of a large eosinophil infiltrate may suggest MCT. Although cytology may allow us to confirm the diagnosis, it provides little prognostic information. Histopathology allows us to grade the tumor so we can predict biologic behavior and make appropriate treatment recommendations.

Tumor grade allows us to predict if wide surgical excision will have a high probability of achieving a cure. When a MCT is graded as low to moderate grade (grade 1 to grade 2 intermediate), wide surgical excision or treatment with radiation therapy is likely to result in complete local control. Because the likelihood of metastastsis is low in these tumors, cure is a reasonable expectation (>85%).

When a MCT is given a grade of high grade 2 or grade 3, pre-existing microscopic metastasis is very likely. In all cases, treatment of the primary tumor and draining lymph nodes with aggressive surgery or radiation therapy is recommended, followed by chemotherapy. While the treatment approach does not differ for high grade 2 and grade 3 tumors, the prognosis is much worse for patients with grade 3 MCT. Depending on the tumor stage and completeness of local control, cures are common for high grade 2 mast cell tumors but rare for grade 3 tumors.

 

Surgery: 3 cm margins!
The most frustrating feature of MCT is how extensive they can extend locally and how quickly the higher grade tumors can metastasize, regardless of their gross appearance. Mast cell tumors are notorious for their invasive nature and tendency to extend far beyond visible margins. If 2-3 cm lateral surgical margins and two fascial planes deep, are not obtained, chances are good that the tumor will not be adequately excised. A surgical margin of a couple of millimeters is not adequate, except for very low-grade (grade 1) mast cell tumors. When surgical margins are very close, a second surgery should be recommended as soon as possible. It is impossible to comment of completeness of surgical excision and predict biologic behavior of mast cell tumors without histopathologic evaluation of the entire tumor.
Depending on where the tumor is located, it may not be possible to obtain 3 cm surgical margins (ie. distal extremity). In those cases, it is appropriate to perform a "debulking" surgery followed immediately by radiation therapy. Depending on the situation, chemotherapy may be recommended in conjunction with or in lieu of radiation therapy. Administration of prednisone alone (1 mg/kg q 24 hours) for 5-7 days prior to surgery may result in sufficient reduction of the tumor mass and associated inflammation thereby increasing success of surgery.

 

Radiation therapy: What are the indications?
While aggressive surgery remains the cornerstone of mast cell tumor treatment, there are times when wide surgical resection is not possible or not desirable. In these situations, debulking surgery is recommended to reduce tumor burden to a minimal microscopic volume and determine tumor grade. Once the surgery site has healed (10-14 days) treatment with radiation can begin. A total of 15 treatments on a Monday-Friday schedule are delivered to the tumor and surrounding tissue (sometimes including regional lymph nodes). For grade 1 and low grade 2 mast cell tumors there is a 93% probability of local control for more than 3 years. For moderate grade 2 to grade 3 tumors, the median duration of local control with radiation therapy is 54 months (range of 30-70 months).

 

When debulking surgery is not possible, radiation therapy can still be effective at achieving and maintaining a local remission of 12 months or longer. A total of 18 treatments are given daily on a Monday –Friday schedule to include the tumor, surrounding tissue and regional lymph nodes. Side effects from radiation therapy resolve within 2-3 weeks post-treatment allowing the patient many months of excellent quality time.

Finally, palliative radiation therapy can be administered on a weekly schedule for 3-4 treatments simply to relieve symptoms from a large mast cell tumor or to delay onset of symptoms for a few months. Long-term results are not likely with this approach but significant improvement in quality of life may occur in those patients with extensive edema and associated discomfort from the tumor.

 

Does location of the primary tumor affect prognosis?
Mast cell tumors of the inguinal or perineal regions have commonly been considered to behave much more aggressively than their histologic grade might predict. Mast cell tumors of the pinna and chest wall near the axilla are surprisingly aggressive in their behavior as well. Low to moderate grade 2 mast cell tumors of the pinna and axilla frequently have identifiable metastases to regional lymph nodes at the time of diagnosis. When not confirmed at diagnosis, it is common for regional lymph node metastasis to become obvious within 3-4 months following surgery. Careful palpation of the regional lymph node is recommended in these cases so the fine needle aspiration of the lymph node can be performed for cytological evaluation.

What about lymph nodes?
Whenever possible, the draining lymph nodes should be biopsied or excised for histopathologic analysis, regardless of gross appearance and tumor grade. The presence of lymph node metastasis worsens the prognosis and necessitates treatment with chemotherapy.

 

When is it essential to stage the patient with mast cell tumor?
Diagnostic tests performed in the staging of MCTs include cytology or biopsy of the draining lymph node; abdominal ultrasound with ultrasound guided aspirate and cytology of the liver and spleen, bone marrow aspirate and cytology, complete blood count and thoracic radiographs. Although the staging process can provide us with essential information, we are very limited by the low sensitivity of these diagnostic tests (small sample size in relationship to large organ size). In the case of a grade I or low grade II MCT that has been completely excised with wide surgical margins, it is unlikely that metastasis has occurred. Early metastasis would not likely be detected during the staging process and therefore is not routinely recommended.

Staging is recommended prior to undergoing an extensive treatment procedure (ie amputation or radiation therapy). Staging is also recommended for any grade III or high grade II mast cell tumor, even if completely excised with wide margins. Histologic evaluation of draining lymph nodes is preferred over cytology in this situation.

Chemotherapy: When to treat?
As with any cancer, chemotherapy for the treatment of mast cell tumor is most effective when combined with other treatment modalities or used early in the course of the disease. Chemotherapy will not be helpful in the treatment of a large mast cell tumor that cannot be excised and has become resistant to prednisone therapy. Chemotherapy is appropriate when tumor cells extend to surgical margins and a second surgery and radiation therapy are not feasible treatment options. Chemotherapy is recommended in all cases with lymph node involvement. Chemotherapy is recommended for all patients with high grade II or grade III mast cell tumors, even when the tumor is excised with wide margins.

 

Prednisone, vinblastine and lomustine are used in combination to obtain the best results with minimal side effects. Adjuvant chemotherapy, following surgery or radiation therapy, results in survival times of greater than 2 years in patients with high grade II mast cell tumors even with metastasis to regional lymph nodes. Chemotherapy is less effective when visceral metastasis has been identified or when the metastatic lymph node size cannot be effectively treated with surgery or radiation therapy. Median survival time with chemotherapy in these patients is 5 months (1-10 months)

Osteosarcoma
A cancer of the bone in the large bones of the leg in large/giant breeds.  Requires aggressive treatment, including amputation.

 

Chondrosarcoma

Mammary Gland Cancer
An aggressive tumor located in the mammary glands that can spread quickly to lymph nodes and lungs.

 

Transitional Cell Carcinoma

What is it?
Transitional cell carcinoma is the most common tumor of the urinary bladder. It is much more common in dogs, with the Scottish Terrier being affected more commonly than most other breeds. This tumor is quite rare in cats, but does occur. It arises from cells that line the bladder, ureters and the urethra, with tumors growing in the bladder, urethra, prostate and even the kidneys. This tumor is usually found at the trigone of the bladder (the area where the urethra, neck of the bladder and the ureters converge). Because of this, it is often impossible to surgically remove all of the tumor. Transitional cell carcinomas can spread or metastasize. The places this tumor commonly spreads to are the sub-lumbar lymph nodes, liver, and lungs.

 

What problems will it cause in my pet?
The three most commonly observed problems are straining to urinate, increased frequency of urination, and blood in the urine. As this mass grows, the difficulty and frequency of urination will increase. Pets with this tumor are frequently treated or diagnosed with recurrent urinary tract infections. If the transitional cell carcinoma spreads to the sub-lumbar lymph nodes (the lymph nodes that are right under the lumbar spine) dogs can develop back pain. If the tumor spreads to the lungs, usually in the very advanced stages of cancer, the dog can develop a cough.

 

What can we do?
Surgical removal of the tumor, if possible should be the first line of defense. Even if the tumor cannot be completely removed because of the size of the tumor or the location of the tumor, debulking (removing a large percentage of the mass) can be helpful in extending the survival time and increase the quality of life for your pet. Chemotherapy is also useful in the management of this disease, especially when used in conjunction with surgery. The drugs that have shown to help dogs with this tumor are Piroxicam (Feldene), mitoxantrone, carboplatin, cisplatin, and doxorubicin (Adriamycin). When used individually these drugs can cause the tumor to shrink and give your pet increased quality of life and cause the clinical signs of straining to urinate, increased frequency of urination and blood in the urine to decrease. The combination of piroxicam and mitoxantrone is currently considered to be the drug combination of choice, as it has resulted in the longest survival times in dogs. Other therapies, such as radiation therapy and targeted therapy (novel therapy) are being investigated.

 

Leukemias

Multiple Myeloma

Soft Tissue Sarcomas

Epuli

Anal sac adenocarcinoma