When treating patients with chemotherapy in your practice or referring to an oncologist, you may get questions from your clients regarding chemotherapy adverse effects (AEs). Most are mild to moderate, with rare patients (<5%) experiencing serious AEs.

The most common AE is gastrointestinal (GI) upset including loss of appetite, vomiting, and diarrhea. For injectable chemotherapy, this tends to occur 2 to 5 days after treatment. Most patients can be treated on an outpatient basis with antinausea medications such as maropitant citrate (Cerenia) or ondansetron. Metoclopramide can be used as well and is of particular benefit for vincristine-induced ileus in dogs. Crofelemer delayed-release tablets (Canalevia) area new drug specifically for chemotherapy-induced diarrhea that modulates hypersecretion of chloride and normalizes fluid influx into the intestinal lumen. Metronidazole, probiotics, and clay supplements also can be used for diarrhea. Hospitalization is recommended for pets experiencing severe GI upset.

The second most common AE of chemotherapy is myelosuppression, particularly neutropenia. Most injectable chemotherapy drugs cause the neutrophil count to be lowest around 7 days after chemotherapy. Some drugs such as carboplatin, dacarbazine, and lomustine in cats can cause delayed neutropenia 2 or more weeks after treatment. In dogs, a neutrophil count of less than 1000 is associated with a significantly increased risk of sepsis. Most oncologists will prescribe antibiotics in a well, afebrile, neutropenic patient with a neutrophil count below 1000 to 1500. Cats are less likely to develop sepsis even in the presence of neutropenia, and antibiotics are typically prescribed only for cats with a neutrophil count below 500 to 1000.

For patients presenting with febrile neutropenia (sepsis) or signs of sepsis in the absence of a fever, aggressive treatment is needed. These pets should be hospitalized with IV fluids and broad-spectrum antibiotics (such as ampicillin/sulbactam [Unasyn] and enrofloxacin). If available, filgrastim (Neupogen) can be used to try to speed white blood cell recovery and shorten hospitalization. However, once pets are neutropenic, the benefit is limited. Neupogen is most effective when given prior to the development of neutropenia (ideally, started 24 hours after chemotherapy) to prevent neutropenia in pets at risk for sepsis, such as those diagnosed with serious infections after chemotherapy was administered. Neupogen should not be given sooner than 24 hours post chemotherapy, as this can potentiate stem cell death from the chemotherapy and worsen cytopenias instead of improving them.

Some chemotherapy drugs have unique AEs that should be discussed with clients. Examples include the following.


Doxorubicin (Adriamycin) can cause damage to the heart and dilated cardiomyopathy. In pets with normal heart function, a cumulative lifetime dose of less than 180 mg/m

 (typically, 6 treatments) is generally well tolerated. A screening echocardiogram is recommended in all large-breed dogs and should be strongly encouraged for dogs at high risk of dilated cardiomyopathy, such as Dobermans, or large-breed dogs with a heart murmur or abnormalities on electrocardiogram. Doxorubicin can cause severe nonhealing wounds if extravasation occurs. To help lower the risk of extravasation, pets should be restrained thorough the entire doxorubicin treatment and the drug should be given only by staff experienced in doing so. It is strongly recommended to have the antidote for extravasation, Dexrazoxane (Zinecard) on site any time doxorubicin is being administered; the sooner it is given, the more effective it is. Efficacy is poor 24 hours post extravasation.

Cyclophosphamide (Cytoxan) can cause sterile hemorrhagic cystitis, or irritation of the bladder. Symptoms of this resemble a urinary tract infection with stranguria, hematuria, pollakiuria, and discomfort. This has been reported in dogs only, although it theoretically could occur in cats as well. Irritation of the bladder occurs due to excretion of a metabolite called acrolein into the urine. The risk for hemorrhagic cystitis can be minimized by using furosemide (Lasix) to encourage dogs to drink and urinate more, as well as taking pets out to urinate every few hours for the first 24 hours post treatment. Clients should be advised to discontinue the drug immediately should lower urinary tract signs occur. If there is no sign of an infection or another cause of the urinary signs and sterile hemorrhagic cystitis is suspected, the drug should be permanently discontinued.


L-asparaginase (Elspar) is an induction agent for the treatment of lymphoma and leukemia. It is typically used to try rapidly inducing remission in pets ill from lymphoma or leukemia. AEs are very different than for other chemotherapy drugs. L-asparaginase can cause allergic reactions, with increased risk the more doses a pet has received. Additionally, L-asparaginase can be so effective that it results in rapid cancer cell death, which can occasionally trigger tumor lysis syndrome. Tumor lysis syndrome typically presents in the first 24 to 48 hours after L-asparaginase administration and can have life-threatening or fatal consequences. Pets with tumor lysis syndrome will demonstrate profound illness shortly after treatment and will have characteristic lab work abnormalities including hyperkalemia, hypocalcemia, and hyperphosphatemia and may present with acute kidney injury and coagulopathies. Treatment for tumor lysis syndrome involves treatment of electrolyte abnormalities, coagulopathies if present, and supportive care.


CeeNU (Lomustine) is hepatotoxic, with liver damage more common in dogs than in cats. Denamarin (S adenosylmethionine and silybin) may help lower the risk of hepatic toxicity. Most dogs with lomustine-induced hepatic toxicity will present with asymptomatic elevation in the alanine aminotransferase (ALT) value on a chemistry panel. If the ALT is more than twice the pet’s baseline, it is recommended to discontinue lomustine and consult an oncologist for guidance. Under an oncologist’s care, lomustine may be continued until more significant ALT elevations are seen depending on the pet’s medical conditions and other options available for treatment.


Rabacfosadine (Tanovea) is a newer chemotherapy drug primarily used for the treatment of lymphoma, with effectiveness for B-cell lymphoma. Rabacfosadine has been reported to cause fatal pulmonary fibrosis in a small percentage of patients. Although this AE is rare, there is often no warning on examination or thoracic radiographs until a pet presents in respiratory distress. Once respiratory distress occurs, treatment options are limited. Despite the risk of pulmonary fibrosis, rabacfosadine is an important tool for treating lymphoma and should not be avoided solely for this reason in pets with limited treatment alternatives. Rabacfosadine has been reported to cause skin reactions that resemble severe superficial pyoderma. Skin reactions typically improve with use of steroids, a treatment delay, and dose reduction or discontinuation of chemotherapy. 

Understanding and discussing these potential AEs with clients is crucial for informed decision-making and ensuring the well-being of pets undergoing chemotherapy. Open communication and collaboration between veterinarians, pet owners, and oncologists play a pivotal role in achieving successful outcomes and maintaining the quality of life for pets battling cancer.

joined Veterinary Cancer Group of San Fernando Valley, a Thrive Pet Healthcare partner, in 2015. A Southern California native, Wiles earned her undergraduate and doctor of veterinary medicine degrees from the University of California, Davis. Her passion for oncology ignited during a rotating internship in Sacramento and then traveled to the East Coast, where she completed an internship and residency in medical oncology at Animal Medical Center in New York, New York. In 2015, Wiles achieved board certification in oncology from the American College of Veterinary Internal Medicine. She has served as president of the Southern California Veterinary Medical Association’s San Fernando Valley Chapter, coordinating monthly educational meetings for local veterinarians. Wiles is dedicated to ensuring a high quality of life for her patients, reflecting her strong belief in compassionate veterinary care.

Articles

Although chemotherapy is well tolerated in dogs and cats, with most pets feeling well through treatment, adverse effects can occur.

Managing chemotherapy adverse effects

This content is sponsored by VCA Animal Hospitals

 readers (and listeners)! We are excited to kick off our pride month celebrations with this special episode of 

. In this episode our host Adam Christman, DVM, MBA, welcomes  guest Josh Sanabria, DVM, to discuss what it is like to be an openly gay veterinary practice owner, the importance of representation in veterinary medicine, and advice for both the LGBTQIA+ and Latinx communities inside and out of veterinary medicine. 

What would be a piece of advice that you would give to your fellow Latino and our LGBTQ+ community in the veterinary medicine field?

: I think to me, the most important thing is, obviously, to accept ourselves, but to be vocal about who we are. Yeah, we have these labels, not just Latinos. But also in the [LGBTQIA+] community, we have different things or how people would see us like fem, masc, or you're a professional in this field, or your skin color—whatever it is, there are so many things that can change how people will see us. I think we need to stop thinking about those things. And just think about who we are and what we want to achieve in life and work as a community. 

But I do believe that we have to be vocal about it because if we just work and do our own thing without showing, like, 'Hey, I'm Latino and I'm proud to be Latino,' or I'll be proud to be gay, you don't get opportunities, or you miss opportunities to connect with people, and then only move forward in life as an individual, but also as a community. And we need that even more now than ever. So I think pride is definitely a reminder every single year to stop caring about what people think. Be yourself and try to be the best you can not only for yourself, but also for your community.

Podcasts

The Vet Blast Podcast kicks of Pride month with special guest Josh Sanabria, DVM

Taking pride in ourselves and workplace

Elizabeth Chosa, DVM, shares some tips for veterinary professionals on this unique career path

Balancing the highs and lows of veterinary medicine

Elizabeth Chosa, DVM, cofounder of Veterinary Hope Foundation, sat down with 

 for an interview at the 2024 Fetch conference in Nashville, Tennessee. She explained that this profession has its ups and downs, and it's essential to remember this balance to avoid focusing solely on the negatives. This revised mindset can help improve well-being not only at work, but also outside of it.

Below is a partial transcript of the video.

 I think it's really important to remember that veterinary medicine is a field that is going to have hard days and hard moments and hard cases. And I think that we need to remember that life is not black and white. A lot of us are perfectionists and a lot of us see things in extremes just by nature. But that's not a good way to live. Because life is not all good or all bad, and veterinary medicine is not all good or all bad. We have to hold space and allow things to be both really hard and also really good at the same time. And I think if we can keep that in mind and live more comfortably in the gray area—work through the hard moments and seek out the good moments—that's one of the keys to being able to enjoy not only this career, but to enjoy life.

Videos

Elizabeth Chosa, DVM, shares some tips for veterinary professionals for professional and personal well-being

With vastly varying body masses, the 11,000 species of birds prove to be a remarkable system with which to decipher the potential causes behind modular evolution, according to investigators at Cornell University in Ithaca, New York.

 A recent study conducted by Andrew Orkney, PhD, lead author and a postdoctoral researcher, and Brandon Hedrick, PhD, assistant professor in the Department of Biomedical Sciences in the College of Veterinary Medicine at Cornell University, revealed that avian wing bone size evolution is limited in heavier species of birds compared to small birds, which showed to have more freely evolving wing bones.

The investigators used a large open-access dataset comprising proportions of 228 micro-CT-scanned bird skeletons spanning various avian lineages and ecological niches and ranging in body mass from 3-g to 11-kg. Applying statistical methods and examining changes in bone proportions across a family tree constructed from publicly available phylogenies, Orkney and Hedrick assessed the impact of body mass on the evolutionary relationships within modules by categorizing birds by size and comparing modular evolution patterns. They also analyzed the co-evolution of different traits across the dataset to determine if variations between predicted trait co-evolution and observations tended to be larger or smaller in birds with different body masses.

The findings revealed that body mass did not affect the “allied evolution” of head and leg bone sizes. However, they found compelling evidence indicating that the relative sizes of bones within the wing evolve together more closely in large birds than in small birds.

“The evolution of wing proportions is more tightly restricted in large birds, which operate under greater mechanical stresses,” Orkney said in a news release.

According to the investigators, this finding could also explain why small birds have developed new styles of flight, like the dynamic soaring of hyper-aerial swifts, bounding flaps of perching birds, and hovering of hummingbirds.

Because birds have "modular" skeletons, their different body parts, such as their wings, legs, and head, can evolve semi-independently.

 However, in large birds, this ability is hampered due to higher levels of stress on their skeletons.

“We found that larger birds have to change different skeletal components of their wings at the same time rather than being able to evolve different parts of their wings independently,” Hedrick said in the release. “It’s easier to change a small part of the wing than all of the wing. It could be that larger animals are less capable of evolving quickly and moving into new niches more generally.”

In birds, this could explain the evolutionary success of small-bodied bird species. For instance, of the 11,000 bird species worldwide, 6500 belong to the category of songbirds, which are characterized by their small size.

 “Hummingbirds are also a very successful and small group, but nothing is as successful as songbirds within birds,” Hedrick said in the release.

The study, published May 28, 2024, also found that bones in the thorax and abdomen of small birds were generally more tightly integrated. The researchers postulated that this unusual evolution in the thorax of small birds could be due to their “bounding” flight pattern, which is characterized by flapping and then propelling with wings folded.

 “I suspect that in order to practice bounding flight, it’s important that all the proportions of the bones within that thoracic and abdominal region match each other well, explaining their tight co-evolution,” Orkney said in the release.

The study also holds potential implications for biological comprehension of animal evolution beyond avians. In forthcoming research, Orkney and Hedrick aim to explore how changes in the thorax and abdomen correlate with wing in small avian species. They will also examine whether the integration in avians differ between birds capable of flight upon hatching and those that are born helpless. Additionally, the researchers will investigate whether bats, having independently evolved flight from birds, adhere to similar evolutionary principles or if there are multiple ways to structure a flying vertebrate.

Wing skeleton may be less restricted in small birds. News release. Cornell Chronicle. May 28, 2024. Accessed May 28, 2024. 

https://news.cornell.edu/stories/2024/05/wing-skeleton-evolution-may-be-less-restricted-small-birds

Orkney A, Hedrick BP. Small body size is associated with increased evolutionary lability of wing skeleton proportions in birds. 

https://doi.org/10.1038/s41467-024-48324-y

New research suggests large avian species’ modular evolution is restricted because of greater skeletal stress

New study reveals small birds have wings that evolve more rapidly than those of large birds

The installment of new veterinary health facilities nationwide improves access to animal care and services. With an increased number of hospitals, pet owners can better access general care and emergency services, which positively impact the overall health outcomes for animals.

Here are 3 recent hospital facilities opening across the United States:

VO Vets Animal Hospital in Trophy Club, Texas

VO Vets Animal Hospital in Trophy, Texas. (Photo courtesy of VO Vets)

VO Vets Animal Hospital recently celebrated the opening of its new facility in Trophy Club, Texas. VO Vets, an American Animal Hospital Association-accredited hospital, provides a range of services including wellness care, dentistry, surgery, urgent care, online booking, same-day appointments, and extended hours. VO Vets is now extending their health and wellness resources to the Trophy Club community in addition to serving the Fort Worth community of pets and pet owners.

“Dallas ranks in the top three of major US cities for dog ownership and half of all Dallas-Fort Worth area homes have a pet, so it’s no surprise there’s a need for more animal hospitals and vet clinics,” said Russell Miller, founder of VO Vets and medical director, in a news release.

 “We’re committed to high-quality and convenient care and are honored to serve the Trophy Club community.”

Miller marked the grand opening with the community last weekend. The event included opportunities for pet patients and their families to meet and greet, a ceremonial ribbon-cutting, a pet photo booth, caricature portraits, a "kids' vet" corner, facility tours, and various other activities. Additionally, there were pet adoptions in collaboration with Four Paws One Heart shelter, local to Texas, for kittens in search of caring homes.

Jennifer Welser, DVM, DACVO, president of Arista Advanced Pet Care. (Photo courtesy of Arista Pet Care)

Arista Advanced Pet Care is set to open its first hospital in 2025 and plans to open several more across the US. Defined by its ingenious shared ownership model, the venture is expected to transform the landscape of specialty and emergency pet care. The operation is being led by Jennifer Welser, DVM, DACVO, president of Arista Advanced Pet Care.

"At Arista Advanced Pet Care, we are committed to revolutionizing veterinary medicine by putting control back into the hands of our dedicated veterinary teams," Welser said in a news release.

 "The veterinary referral industry is over 85% corporate consolidated and our shared ownership model represents a paradigm shift, offering veterinarians a unique opportunity to have a true stake in the success of their practice. We are proud to be at the forefront of this transformative movement in veterinary medicine."

Supported by a team boasting over 25 years of experience in developing the shared ownership model, Arista sets itself apart by constructing new multispecialty referral and 24/7 emergency hospitals devoted to addressing pet health concerns beyond what general practice encompasses. Through collaboration with veterinary owners who have a significant stake and involvement, these veterinary teams are encouraged to establish hospitals within their communities. This innovative approach not only promotes collaboration and the development of unique local cultures but also better addresses the needs of clients and their pets, as well as those of general practitioners and hospital teams.

Red Bank Veterinary Hospital in Red Bank, New Jersey

Red Bank Veterinary Hospital in Red Bank, New Jersey. (Photo courtesy of Red Bank Veterinary Hospitals)

Red Bank Veterinary Hospital recently announced the grand opening of its new hospital, located on 100 Schulz Dr, Red Bank, New Jersey. The new hospital’s design, which has 4 floors of progressive amenities, 52 exam rooms, and is more than 100,000 sq ft, is aimed to foster collaboration among staff members to improve patient care outcomes.

“We are excited to usher in a new era of veterinary care with the opening of our new facility,” said John Anastasio, DVM, medical director at Red Bank Veterinary Hospital in a release by the company.

 “For 40 years, our commitment to excellence has remained unwavering, and we look forward to continuing to serve the community and its furry companions with the highest level of veterinary care.”

With over 400 professionals and 16 specialties, the hospital features advanced diagnostics; a separate entrance and waiting area; an advanced surgery center; a rehabilitation unit; training and development space; pet-friendly amenities; 300 parking spaces with 2 electric vehicle chargers; and a Zen garden, 6 comfort areas, and a client-facing pharmacy aimed to improve client comfort.

Trophy Club pets and pet parents celebrate grand opening of VO Vets Animal Hospital. News release. VO Vets. May 8, 2024. Accessed June 4, 2024.

Introducing Arista Advanced Pet Care: Revolutionizing specialty & emergency veterinary medicine with a shared ownership model. News release. Arista Advanced Pet Care. May 28, 2024. Accessed June 5, 2024. 

Red Bank Veterinary Hospital unveils new state-of-the-art facility. News release. Red Bank Veterinary Hospitals. May 18, 2024. Accessed June 5, 2024. 

https://www.redbankvet.com/2024/05/red-bank-veterinary-hospital-unveils-new-state-of-the-art-facility/

Take a look at these 3 veterinary centers newly opened or coming soon

Clinic center: Latest hospital openings in the United States

IDEXX Laboratories Inc has expanded its test menu for the Catalyst platform with the launch of the Catalyst Pancreatic Lipase Test, a single-slide solution for canine and feline patients suspected of pancreatitis. According to a company release,

 the test can run effortlessly alongside chemistry profiles, which can help lead to quicker diagnoses and enhanced patient outcomes. IDEXX plans to make the Catalyst Pancreatic Lipase Test available in the US and Canada September 2024, with a global rollout to begin in the fourth quarter of 2024.

“The Catalyst Pancreatic Lipase Test marks the tenth menu addition launched for the Catalyst platform since 2012, reinforcing our commitment to extend the clinical value and diagnostic capabilities of our technologies,” Jay Mazelsky, president and CEO of IDEXX, said in the release.

 “We are pleased to deliver a highly requested test, which will streamline the diagnostic workflow and equip veterinarians with the necessary clinical insights for prompt action.”

The Catalyst Pancreatic Lipase Test, along with VetConnect PLUS software, offers an essential tool for managing pancreatitis over time. VetConnect PLUS seamlessly integrates past data and test results, making it easy to evaluate patient progress and treatment effectiveness.

"The Catalyst Pancreatic Lipase Test is the first test to use dry chemistry slide technology that specifically measures pancreatic lipase and correlates with the IDEXX Reference Laboratories Spec cPL and Spec fPL tests to provide the most accurate, quantitative results patient-side for dogs and cats,” Jörg M. Steiner, DrMedVet, PhD, DACVIM-SA, DECVIM-CA, AGAF, told IDEXX.

Pancreatitis is a common disease among dogs and cats and can be treated if caught early. During a previous 

, he explained that more than 90% of pancreatitis in dogs and cats is idiopathic. However, Steiner stated, “there's a variety of things that are considered risk factors: hypertriglyceridemia, high-fat diets, hypercalcemia, car accidents, surgical trauma, hypovolemia, etc.”

Oftentimes nothing pathognomonic that may be noted during a physical examination; however dehydration, anorexia, nausea, vomiting, fever, lethargy, abdominal pain, and diarrhea may present in patients with pancreatitis. This can also be challenging, however, because these clinical signs may mimic those of many other conditions.

With the launch of the Catalyst Pancreatic Lipase Test, more patients could potentially receive an early diagnosis, aiding in a quicker treatment strategy and recovery. According to IDEXX, the new test can give quantitative results in under 10 minutes.

IDEXX also plans to release the Catalyst SmartQC Control, a quality control testing system that is 90% faster than current methods.

 Coming in the fourth quarter of 2024, the Catalyst SmartQC Control loads in under 15 minutes, improving time efficiency for veterinary staff.

IDEXX expands test menu for the Catalyst platform to support veterinarians globally in giagnosing pancreatitis. News release. IDEXX Laboratories Inc. June 4, 2024. Accessed June 5, 2024. 

https://www.idexx.com/en/about-idexx/news/idexx-expands-test-menu-catalyst-platform-pancreatitis/

Yankowicz S. Quick tips on understanding and treating pancreatitis. 

. January 16, 2024. Accessed June 5, 2024. 

https://www.dvm360.com/view/quick-tips-on-understanding-and-treating-pancreatitis

Ward E, Panning A. Pancreatitis in dogs. VCA Animal Hospitals. Accessed December 21, 2022. 

https://vcahospitals.com/know-your-pet/pancreatitis-in-dogs

IDEXX expands its test menu for the Catalyst platform to enhance diagnosing for this common disease