Surgery for removing dog tumors is medically referred to as "surgical oncology" and remains one of the oldest ways of treating cancer. In fact, in the past, surgical removal was the only effective way to treat many types of tumors. Nowadays, on top of surgery for removing dog tumors, cancer treatment may also combine radiation therapy and chemotherapy. While in some cases surgery may successfully treat certain localized tumors, it's unfortunate that even the most aggressive surgical procedures cannot stop the spread of certain types of cancer.
Surgery for Removing Dog Tumors
In the last years, there have been great advancements in the field of surgical oncology. Improvements in the field of anesthesia and surgical procedures have lowered mortality rates, even for invasive procedures. Surgical removal of tumors in dogs remains the most effective strategy for controlling the growth of certain tumors.
In cases where the whole tumor cannot be removed (as it may happen in the case of soft tissue sarcomas or hemangiopericytomas), the combination of radiation therapy along with surgery may turn helpful. Forms of cancer that spread, may not be controlled completely with surgical intervention and may require the addition of chemotherapy so to prevent the spread of the cancer to other body parts.
Surgery at times may be carried out for taking a biopsy for diagnostic purposes. Tissue biopsies or bone biopsies that are taken prior to surgery are known as "pre-operative biopsies" and they offer the advantage of determining the grade of a tumor before proceeding to a potentially aggressive surgery such as a leg amputation.
There are different types of surgeries performed for cancer biopsies. An incisional biopsy involves removal of a small wedge of tissue from the mass, while an excisional biopsy involves removal of the entire mass. An excisional biopsy can therefore be diagnostic or both diagnostic and part of the treatment plan should the sample removed turns out being cancerous (hopefully, in such a case it was removed with clean margins!). All biopsied tissues should be examined under the microscope at a lab to determine what it is.
"If excisional biopsy it to be used to obtain a diagnosis, it is wise to forewarn the owner that this test is only being used to obtain a diagnosis, and that additional diagnostics or treatment might be necessary, based on the results."~Dr. Douglas H. Thamm, veterinary oncologist
Surgery for Cancer Treatment
Surgery for removing dog tumors is often carried out when the vet has taken a sample of the tissue (often through fine needle aspiration, impression smears or tissue biopsy) and the microscopic evaluation of cells and tissues reveals presence of abnormalities suggestive of cancer.
In this case, a diagnosis of cancer is generally already made (or tentatively made) and the goal of surgical intervention is of primary treatment.
Surgery for dog tumor removal is often indicated when the tumor is solid. Most solid tumors can be removed surgically unless the mass is located in an area that is difficult to completely remove.
Complete treatment is only an option in the case of localized cancers that do not have a tendency to spread and involve multiple organs (metastatic). Metastatic cancer may require the addition of chemotherapy or radiation in hopes of prolonging life.
Surgery may not be an option in the case of a cancer that has taken over, such as in the cases of a cancer that has already spread to the lungs or in the case of a frail, cancer-stricken weakened dog who is of advanced age. In the medical field there is a saying: "the surgery was a success, but the patient died" which indicates the importance of balancing out potential benefits of surgery against potential risks to the patient.
"Examples of tumors best treated and possibly cured with surgery alone include canine oral tumors such as squamous cell carcinoma and fibrosarcoma, cutaneous mast cell tumors, mammary tumors, soft tissue sarcomas, splenic or hepatic tumors with painful capsular distention, nail bed tumors, synovial cell sarcoma causing bone lysis, and tumors of the ear canal."~ Dr. Timothy M. Fan, Louis-Philippe de Lorimier
Leaving it to the Pros
Surgery for tumor removal in dogs should be ideally performed by a board-certified veterinary surgeon. A specialist in surgery can do a much better job in removing tissue and obtaining clean margins the first time, so that a second surgery to remove any tissue left behind is not necessary. This can help save money in the long run (surgery for dog tumor costs may range anywhere between $300 to $3,000 depending on various factors) and provides the best chance a cure.
A specialized surgeon may choose to perform a pre-surgical biopsy to get an idea of exactly what type of cancer he or she is dealing with. A CT scan on top of this, can help determine the extent of the tumor. This is important because certain types of cancer require a more aggressive surgical approach with wider margins.
For example, a cancer such as a hemangiopericytoma has tentacle-like projections which can potentially extend far from the main mass. Leaving behind any of these projections in the tissues will lead to incomplete margins, making this type of tumor 10 times more likely to recur, explains veterinary oncologist Dr. Susan Ettinger. This would mean that a second surgical procedure would be required to remove the mass another time.
According to veterinarians Maura G. O' Brien and Stephen J. Withrow, the more procedures required, the less the chances for obtaining a disease-free state. Succeeding in the first surgical attempt is therefore ideal and success often depends on a multitude of factors such as carefully evaluating results of preliminary diagnostic tests, staging procedures and surgical skill.
A veterinary surgeon should be able to remove the tumor in one piece, include a layer of surrounding normal tissue and take care in not overly manipulating the tumor which can lead to rupture and potential local tumor dissemination.
Surgery for removing dog tumors requires attentive post-surgery care. The job of the surgeon is not over once he closes up the incision and completes the surgery. Surgical removal of a tumor in dogs can be associated with postoperative pain, blood loss and other complications. The surgeon will take several steps though to avoid these complications as much as possible.
Pain medications provided during and after the procedure can help reduce the pain and stress associated with recovery. The owner should be coached on post-surgery care, how to prevent the dog from traumatizing the area (often an Elizabethan collar is provided), how to take care of the surgical incision and any associated grafts and bandages if present.
Complications from surgery for removing dog tumors may include infections, wound dehiscence (a wound that ruptures along a surgical incision), lowered immunity (from surgery, blood transfusions, chemo), tumor recurrence and tumor spread.
Owner of dogs are often instructed to see the vet for follow-up appointments to assess proper healing. Depending on the type of tumor removed, dog owners are instructed on how to monitor for signs of trouble such as recognizing any enlarged lymph nodes or masses suggestive or tumor resurgence. Dog owners should also monitor for other more widespread, systemic signs such as weight loss, loss of appetite, coughing and lethargy.
- Dog Cancer Blog: Staying vigilant with mass aspirates
- Textbook of Veterinary Internal Medicine, Stephen Ettinger, Edward Feldman
- DVM360: Treating cancer pain in dogs and cats
- DVM360: Dispelling the myths of veterinary cancer and its treatment (Proceedings)