Breaking Down Barriers
There are encouraging advancements in oncology treatments, but access is still an obstacle for some pet owners.
The numbers used to be daunting for pet owners seeking cancer treatment for their dog or cat. Neal Mauldin, DVM, chief medical officer, PetCure Oncology, said either the treatments needed were too many, or the distance to a facility for treatment was too far.
“In the old days when you were talking about (conventional radiation therapy) – Monday through Friday for four weeks – if you lived ten hours away from radiation facility, that probably wasn’t a doable thing,” he said. “You didn’t want to send your dog away for 4-6 weeks, and you couldn’t drive back and forth. The protocol limited access to a lot of families.”
Fortunately, advances such as stereotactic radiation therapy have increased access for families with dogs and cats with cancer that in the past they wouldn’t have had it. They’re also popular because when you’re treating patients only 1 to 3 fractions vs. 20, “all of a sudden the travel becomes much less of a barrier for a lot of families,” said Dr. Mauldin.
Expand the Reach
In order for cancer care to be truly effective for the pet population, expanded access has to go hand-in-hand with technology advances. One of the biggest barriers to access and expansion from a provider’s perspective is the fact that there are so few veterinary radiation oncologists in the world. “There are about a hundred of us running around,” said Dr. Mauldin. “We’re trying to expand the reach.”
PetCure Oncology is one animal health organization that hopes to do just that. It currently has a network of six hospitals nationwide now, with a seventh location in the works. One location is a standalone facility that is an imaging and radiation therapy center, and also has a neurology service associated with it. The other sites are embedded within specialty hospitals.
“We see that number growing over the next couple of years,” Dr. Mauldin said. Currently, their locations are on the West or East Coasts, as well as the Southwest. PetCure’s long-term goal is to have a presence in the top 25 to 30 population markets in the United States. “We’ve got a fairly aggressive growth strategy in play.”
PetCure basically operates as a tertiary care facility, Dr. Mauldin said. All patients are referred and come from different places. For instance, a specialist who detects a brain tumor in a patient may refer the pet owner to PetCure for stereotactic. Primary care veterinarians are also a big source of referrals. “We’ll see a fair number of patients being referred to us internally by the other specialists within whatever hospital we’re embedded in, but we also get out into the community and do vet-to-vet outreach,” he said. “We have program directors in each market that are responsible for getting out and talking to vets and setting up CE events. The number of outside referrals is pretty impressive as well. About 50/50 at most of our facilities.”
PetCure also has a “fairly robust” teleconsultation portal, Dr. Mauldin said. “With hospitals we’re affiliated with, we can remote in and do a teleconsult with a family. There’s always a doctor on-site with that family, but we will remote in.”
The final path to access is a pet advocate program.
“If you’re a family member who has a dog that just got diagnosed with a nasal tumor and is searching for information on the internet, you may come across our pet advocate group, which is manned by veterinary technicians who serve as a liaison if you have questions,” he said. “We’ll help facilitate getting medical records and getting those records reviewed by one of our medical oncologists, or one of our radiation oncologists. And then if appropriate, we can either facilitate getting you in to see one of our onsite radiation oncologists, or we can work with doing a remote teleconsult with your doctor.”
Standard of Care
Veterinary hospitals across the country are investing more in cancer care, with expansions in services, equipment, and facility upgrades. Earlier this year, VCA Northwest Veterinary Specialists, a suburban Portland, Oregon, specialty hospital announced it was expanding to accommodate a linear accelerator for cancer treatment. Ground was broken in mid-March on the hospital addition. VCA Northwest Veterinary Specialists, which employs nearly 40 veterinarians, 20 of them board-certified, expected the Varian Trilogy radiotherapy system to become operational in late 2019, according to
Today’s Veterinary Business.
“The addition of a state-of-the-art linear accelerator to Northwest Veterinary Specialists will revolutionize the way cancer patients are treated at our hospital, and likely in the Pacific Northwest, in general,” said Matt Dowling, DVM, MS, DACVIM. “Radiation therapy is the standard of care for some cancers like brain tumors and nasal tumors. Radiation also plays a very important role in other types of cancers including oral tumors, bone tumors, anal sac tumors, urogenital tumors, soft tissue sarcomas, and a variety of other skin cancers.”
Northwest Veterinary Specialists’ new linear accelerator will have intensity-modulated (IMRT) and stereotactic (SRT) treatment capabilities. “These types of radiation treatment allow us to more precisely target tumors, which allows for improved disease control and fewer side effects from treatment.”
Stereotactic radiation therapy tends to treat a relatively small subset in that it focuses on tumors that need local control, Dr. Mauldin said. Those areas include soft tissue sarcoma, mass cell tumors, brain tumors, and nasal tumors.
“The interesting thing is that as stereotactic radiation becomes more available – both in veterinary and human medicine – we’re learning that there’s a significant component of immune response associated with those patients,” he said. “The kinds of cancers we’re treating are actually increasing. The kinds of tumors we think are reasonable targets for radiation therapy are increasing.”
The world of stereotactic radiation is relatively new in the veterinary space, but pet owners are already seeing one of the biggest advantages of stereotactic radiation – an increase in anticipated survival times. “They appear to be the equivalent to – if not better than – what we see with conventionally fractionated radiation therapy for a lot of tumor types,” Dr. Mauldin said.
The second major advantage is that the side effects are much lower. “For conventional radiation therapy, there were large volumes of normal tissue that got irradiated along with the tumor,” Dr. Mauldin said. “That’s what leads to all the side effects that you see. With stereotactic, you are treating the tumor with a very narrow margin of normal tissue, so the side effects tend to be much less.”
Mauldin said the final benefit, perhaps the major benefit for some pet owners, is the fact that they aren’t treating the patients with a high number of anesthetic events. “Every time in veterinary radiation when we treat a patient, there is general anesthesia involved. Now, we may treat that 14-year-old dog with a brain tumor with 1 to 3 fractions instead of 20, so they only have 1 to 3 anesthetic events that they have to go through. One of the biggest concerns our families identify is the anesthetic events their pet has to get through a full course of radiation.”
Once the patient has been treated, having a close working relationship among the client, the primary care veterinarian, and the oncologist is very important for the appropriate management of the patient’s cancer said Dowling.
“After the patient has finished a cancer treatment (surgery, radiation, and/or chemotherapy), it is often necessary to closely monitor these patients with frequent blood work and diagnostic imaging (chest X-rays, abdominal ultrasound) to survey for evidence of cancer recurrence or metastasis and to ensure that the patient is maintaining overall good health,” he said. “The primary care veterinarians are often those veterinarians performing these cancer surveillance tests and following up with the oncologist as needed.”
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Dr. Neal Mauldin, DVM, chief medical officer, PetCure Oncology, said that nationally, veterinary specialists treat anywhere from 10,000 to 12,000 cancer patients a year. PetCure treats somewhere between 600 to 800 a year across all of its sites. “We see that increasing as we increase access,” he said.
Common types of cancer
“Lymphoma, in both dogs and cats, is the most frequently diagnosed cancer in our veterinary patients,” said Matt Dowling, DVM, MS, DACVIM, VCA Northwest Veterinary Specialists. “Lymphoma involving peripheral lymph nodes (non-Hodgkin’s-like disease) is the most common form of lymphoma diagnosed in dogs and lymphoma involving the gastrointestinal tract is the most common form of disease diagnosed in cats.”
Veterinary hospitals offering oncology treatments have some unique inventory needs. “It is not uncommon for chemotherapy medications and associated supplies to be on back-order for indefinite periods of time (most frequently due to manufacturing delays),” said Dowling. “These supply backorders can tremendously affect our patients – at times, altering recommended treatment protocols simply due to product unavailability.”
VCA launches network of VCA Pet CancerCare™ Centers
VCA Animal Hospitals announced in late August the launch of its network of 35 VCA Pet CancerCare™ Centers across North America. At VCA Pet CancerCare Centers, multidisciplinary oncology teams will design individualized treatment plans for pets using the latest in medical health care technology to create the most efficient treatments available, which are often less invasive with fewer side effects, so pets remain comfortable throughout treatment, the company said in a release.
“At VCA Pet CancerCare Centers, we are leading cancer care into a hopeful new era with longer lifespans and improved quality of life,” said Dr. Zack Wright, director of oncology at VCA Animal Diagnostic Clinic in Dallas, Texas. “Our dedicated oncologists across the network are committed to working with primary care veterinarians to make advanced cancer care accessible to pet owners, with the goal always being extended, high quality of life for our patients.”
VCA Pet CancerCare Centers will be treated under the guidance of board-certified oncologists who have years of advanced training and experience in their areas of specialization, including medical oncology, radiology, and surgery. Our multidisciplinary oncology teams will design individualized treatment plans for each patient using the most advanced and efficient therapies available – from chemotherapy and radiation therapy to surgery and immunotherapy.
For a full list of VCA Pet CancerCare™ Centers, please visit vcapetcancercare.com.
Common cancer treatments
According to PetCure Oncology, depending on the specific type of cancer a pet has, treatment may include the following, either alone or in combination:
Surgery is often the first line of treatment when localized cancer can be removed completely. The best-case scenario will always involve having the patient in one room and the tumor in another. In situations where the prospect of total removal is uncertain, however, the decision becomes more difficult.
Powerful drugs are used to destroy or damage cancer cells, particularly blood-cell cancers such as lymphoma and leukemia, and cancers that have spread (metastasized) or are likely to. It may be given orally (pills), intravenously, or directly into a tumor. Fortunately, dogs and cats generally tolerate chemotherapy much better than human patients.
Stereotactic Radiation (SRS/SRT)
A leading treatment option in human cancer care is now available for pets. This advanced form of radiation therapy is highly effective in treating cancer and is usually delivered with the intent to cure, as opposed to merely easing symptoms. Utilizing sub-millimeter precision that is unprecedented in veterinary medicine, stereotactic radiation (SRS/SRT) directly targets the tumor while mostly sparing the surrounding healthy tissue. It can even be used to treat some cancers previously considered untreatable in sensitive areas of the body such as the brain, spine or lungs. SRS/SRT is a nonsurgical procedure that eliminates most side effects and requires only 1-3 treatments, an 80-95% reduction in both treatment sessions and anesthetic events compared to conventional radiation therapy. This means your pet is spending less time in the hospital and can get back to their favorite activities much sooner.
Conventional radiation therapy
Conventionally fractionated radiation therapy (CFRT) uses targeted radiation to shrink or destroy cancers that cannot be safely or completely removed by surgery alone. It can also be utilized in conjunction with, or in place of, chemotherapy, or delivered following surgery if the initial procedure is unable to completely remove cancer. CFRT is typically administered in 15-21 treatment sessions over 3-7 weeks. Pets will need to be anesthetized to ensure they remain still during each session.
Sometimes pet owners opt not to treat cancer for a number of reasons, particularly if a cure is not possible. In this case, palliative care – which includes pain management – can be used to increase a pet’s comfort and quality of life. Typically delivered in weekly low-dose radiation treatments over 3-6 weeks, the goal is to relieve symptoms such as pain, bleeding and decreased mobility.
A biological therapy that involves the use of antibodies to boost the body’s natural defenses by either stimulating the immune system to fight the cancer cells or by counteracting signals produced by cancer cells that suppress the immune system.
The use of cold temperatures to kill cells. It is best suited for small, superficial tumors and is commonly used in areas such as the skin, eyelids, oral cavity, and peri-anal region.
Radioactive Iodine I-131
Hyperthyroidism is one of the most common endocrine disorders diagnosed in cats. It can be treated surgically, medically or with radioactive iodine therapy (I-131). Most cats (90-95%) will have a benign, functional thyroid adenoma (tumor) that produces excessive thyroid hormone but has no risk of metastasis. A very small percentage of cats will have a thyroid carcinoma. Treatment with I-131 is the only option to treat the dysfunctional thyroid tissue with minimal impact on normal tissue.
Source: PetCure Oncology