Aggressive surgical techniques are indicated in dealing with soft tissue sarcomas (STS). If STS are approached casually, they are incompletely or inadequately removed. With residual cells present, they often grow back with a vengeance.

STS may manifest anywhere but are seen most commonly in the skin and subcutaneous tissues. STS are clinically underestimated too often. The actual risk of recurrence is predictable at the start. Fibrosarcoma (FSA) is a brutal killer because it may fool some practitioners with its mild-mannered histology, but it recurs even after the best planned surgeries. Be aware of the "fibroma" found on the muzzle of golden retrievers and dobermans. This malignancy disfigures the muzzle and is fatal if not arrested when it is small.

Hemangiopericytoma and schwannoma behave just as insidiously. If they appear on the limb, good margins are nearly impossible without a graft. Intralesional chemotherapy and intraoperative radiation therapy, which are delivered to the open surgical tumor bed at the time of surgery, are helpful situations when the limb is requested to be salvaged.

All STS should be considered malignant. Unfortunately many were given kind names ending in "oma." They often kill otherwise healthy old dogs because they were initially underestimated. Malignant melanoma and squamous cell carcinoma share similarities in that they seldom arise in the skin of dogs. Both may appear in the mouth and in nail beds mimicking osteomyelitis.

Whenever a toe is festering in a senior dog, X-rays and a deep punch biopsy with a 2mm tool are indicated from the very first visit. Give antibiotics, by all means, but get the diagnosis on that first presentation before it metastasizes. Your biopsy will usually come back as either squamous cell carcinoma or malignant melanoma of the digit, not what it appeared to be. Check the local nodes for metastases.

In the front limb, the prescapular node is more likely than the axillary lymph node to contain mets from digital neoplasia. The popliteal node is the first to catch the metastatic cells for rear leg digital tumors. However, check the inguinal nodes and the sublumbar nodes for metastasis. Both of these malignancies met to the chest. I treat both of them similarly with carboplatin every 21 days four to six times, then every two months for one year if the family can afford it.

Felines all over the world have a genetic predisposition for mutations, especially in chronic inflammatory tissue. At some point in chronic inflammatory reactions or in their inflammatory bowel disease, cells undergo a transition from a pre malignant status into various types of malignant sarcomas. examples of this would be feline Vaccine Associated Sarcoma (VFVAS) and GI lymphoma. FVAS has a high rate of fatality because of persistent recurrence within one year. Tumor free intervals of one year occur in only ten percent following surgery alone and only in 50 percent of patients that receive a combination of surgery and radiation.

Intraoperative chemotherapy implants with megadose intraoperative radiation therapy may increase the tumor-free interval for these patients because it may reduce growth factors in the tumor bed and blunt the mitotic ability of residual cancer cells. Patient fatality from palpable soft tissue sarcomas most often results from not diagnosing and treating the tumors aggressively at the first opportunity. Clients need more education so they will take their pets to their veterinarian at earlier stages of their pet's cancer, while practitioners need to do more vigorous FNAs and biopsies at that first visit, followed by definitive treatment.

Bone Cancer
Senior dogs exhibiting lameness need X-rays before dispensing N-SAIDs. Over the past five years we have seen more advanced lesions and pathologic fractures in dogs on Rimadyl or Etogesic. It's easy to presume lameness comes from arthritis.

Caution clients in writing that without diagnostic X-rays, arthritis is not proven as the cause of the lameness. If you suspect bone cancer on the X-rays, a biopsy is not needed for confirmation unless a biopsy makes a difference on how the patient is treated.

The Veterinary Cancer Society supports a radiographic diagnosis for osteosarcoma confirmed by a radiologist or an oncologist. Biopsy is warranted if the client insists on biopsy or if the lesion is atypical. This procedure yields low accuracy and, therefore, may need to be repeated. Send samples at the time of amputation for confirmation.

Limb salvage is an option that clients want to know about. Consulting with an oncologist is very helpful when the caregiver is struggling with a decision of salvage vs. amputation vs. "Pawspice" (end of life care).The NSAID, piroxicam at O.3 mg/Kg PO once daily is beneficial for pain control in nonamputated dogs and cats. OSA in cats is rare, and they tend to do much better than dogs following amputation even without chemotherapy. Bone cancer in cats is rare, and cats tend to do much better than dogs following amputation.

I usually recommend amputation followed by carboplatin chemotherapy every 21-30 days for four to eight treatments. Networking with another three-legged-pet-family helps people visualize the pet's life after amputation.

Nasal Cancer
Senior dogs develop nasal cancer rather insidiously. Nasal cancer composes five to seven percent of all their tumors. Cats rarely develop nasal cancer. The most common tissue types that afflict cats' nasal passages are lymphoma, squamous cell carcinoma and respiratory adenocarcinomas. These malignancies need to be distinguished from "crypto" (a fungal disease which invades bone) of the nasal passages which mimics nasal cancer.

The early warning signs of nasal cancer are unilateral nasal or ocular discharge, epistaxis, loss of smell, dryness of the nasal planum, uclers of the nasal planum and pawing at the face. White cats exposed to the sun are prone to develop squamous cell carcinoma (SCC) of the nasal planum. In dogs and cats with late stages of nasal cancer, symptoms include facial or palatine deformity, loose teeth and pawing at the face.

Unfortunately, most cases of nasal cancer have been present three to five months by the time of diagnosis. Rhinoscopy and biopsy of the nasal passages may need to be repeated more than once to confirm nasal cancer.

Since most dogs with nasal cancer survive five to seven months with no treatment, it may be difficult to recommend intensive treatment protocols, especially in advanced cases.

Cats with nasal planum SCC benefit from nosectomy or radiation therapy. Intralesional therapy with carboplatin used in conjunction with radiation therapy may provide additional anticancer benefits for cats with SCC of the nasal planum.

In dogs, the benefit of radiation therapy with or without rhinotomy for nasal cancer is controversial. Most oncologists prefer to bypass rhinotomy in dogs and treat nasal malignancies with cobalt or linear accelerator radiation therapy on a three-times-per-week schedule.

Each case needs to be selected for the pet's anticipated survival past the five to seven month "no treatment mark."

Chemotherapy is the less-aggressive choice of many oncologists for clients who decline radiation therapy for their pets. Rotating Carboplatin, Adriamycin or mitoxantrone every 21 to 30 days are most frequently chosen to palliatively treat nasal cancer.

Dr. Villalobos, the Leo Bustad Companion Animal Veterinarian of 1999, is the editor-in-chief of the American Association of Human Animal Bond Veterinarians Newsletter. She owns Animal Oncology Consultation Service in Woodland Hills and a partnership with VCA Coast Animal Hospital and Cancer Center in Hermosa Beach, Calif. Her e-mail is dralicev@aol.com.