ACVIM small animal consensus statement on safe use of cytotoxic chemotherapeutics in veterinary practice

Chemotherapeutics in Equine Practice

Chemotherapy is the treatment of cancerous cells through the use of cytotoxic drugs. Whilst the use of systemic (intravenous) chemotherapy in equine practice is generally limited to the management of lymphoma, cytotoxic drugs are commonly used in the treatment of accessible skin tumors, either by topical application in the form of ointments or injected intralesionally. These drugs should be employed with caution due to the risk of serious adverse effects. In addition, extreme caution should be followed when preparing, handling, administering, and disposing them, due to their carcinogenic, mutagenic, and teratogenic properties.

Metronomic chemotherapy: bridging theory to clinical application in canine and feline oncology

Veterinary oncology has experienced significant evolution over the last few decades, with chemotherapy being currently applied to several neoplasms with therapeutic success. Traditionally, chemotherapy protocols are based on classic cytostatic drugs under the concept of maximum tolerated dose (MTD), which has been associated with a greater risk of toxicity and resistance. Thus, new therapeutic alternatives have emerged, such as metronomic chemotherapy (MC), introducing a new paradigm in cancer treatment. MC consists of administering low doses of chemotherapy drugs continuously over a long period of time, modulating the tumour microenvironment (TME) due to the combination of cytotoxic, antiangiogenic and immunomodulatory effects. This multi-targeted therapy has been described as a treatment option in several canine and feline cancers since 2007, with positive results already published in the literature, particularly in mammary carcinomas and soft tissue sarcomas in dogs. The aim of this review article is to describe the current knowledge about the use of MC in small animal oncology, with emphasis on its mechanisms of action, the most commonly used drugs and clinical outcome.

Pegylated-l-asparaginase therapy for feline large cell lymphoma: 82 cases (2017-2020)

OBJECTIVES

The present study aimed to investigate pegylated-l-asparaginase monotherapy for feline large cell lymphoma as a potential alternative to palliative corticosteroids treatment in animals whose owners declined cytotoxic chemotherapy.

METHODS

A retrospective, descriptive case series of cats treated initially with pegylated-l-asparaginase as a sole therapy for feline large cell lymphoma is reported. The treatment protocol consisted of 12 intramuscular injections of pegylated-l-asparaginase with increasing intervals. If cats were unresponsive to pegylated-l-asparaginase monotherapy, a second-line treatment was initiated. Signalment, origin of lymphoma, staging, treatment, possible adverse events and follow-up data were extracted from the medical records. Responses and survival data were analysed.

RESULTS

Eighty-two cats with lymphoma of five different anatomic types were included: alimentary, abdominal extra-alimentary, peripheral nodal, nasal/nasopharyngeal and other (mediastinal, renal [solitary] and miscellaneous combined in one group for analytical purposes). The response rate was 74.1% (95% confidence interval = 63.4-83.5) with 38.3% (95% confidence interval = 27.8-48.8) in complete remission. The median disease-free period and calculated overall survival time were 70 days (12-1702+) and 79 days (1-1715+), respectively. The response rate was significantly correlated with the origin of the lymphoma and the combined group had a significantly lower response rate (P = 0.035). Twenty-four cats were also treated with corticosteroids. There was no significant difference in outcomes between the group treated with or without corticosteroids. Adverse events were present in a small number of cats (14/82). The majority of these adverse events were mild to moderate in 5/14 cats; however, the adverse events were severe enough to cause discontinuation of therapy.

CONCLUSIONS AND RELEVANCE

Based on the response rate and median disease-free period, treatment with pegylated-l-asparaginase is inferior when compared with historical chemotherapy protocols. However, some cats demonstrated an exceptional long disease-free period. Therefore, pegylated-l-asparaginase could be offered as an alternative to corticosteroid therapy alone. Further studies are needed to evaluate the additional benefit over palliative corticosteroid monotherapy.

No Excess Cancer Risk among Veterinarians in Denmark, Finland, Iceland, Norway, and Sweden after the 1980s

The cancer profile of veterinarians has received little research attention, despite the profession potentially being exposed to a wide range of known and suspected carcinogens. In this large-scale cohort study, we assessed cancer incidence in veterinarians in Denmark, Finland, Iceland, Norway, and Sweden, across more than 40 years (1961-2005). The cohort comprised 4708 veterinarians and 119,503 person-years at follow-up. The overall cancer incidence in veterinarians was close to the incidence in the total population in all countries and in all age groups. In male veterinarians, the standardized incidence ratios (SIR) in 1961-1990 were elevated for colon cancer (1.86, 95% confidence interval (CI) 1.39-2.44), prostate cancer (1.35, 95% CI 1.07-1.67), and especially skin melanoma (3.62, 95% CI 2.78-2.84), while there was no longer any statistically significant excess in the more recent follow-up period. Decreased SIRs were observed for lip cancer (0.11, 95% CI 0.00-0.62), laryngeal cancer (0.38, 95% CI 0.12-0.89), lung cancer (0.59, 95% CI 0.47-0.74), and stomach cancer (0.58, 95% CI 0.38-0.86), without a marked change in SIR over time. Non-significant excesses among male veterinarians were also observed in Hodgkin lymphoma (1961-1990 only), and leukaemia. This multi-country study indicates that there was an elevated incidence of several cancer types among male veterinarians before the 1990s but not after that. Some of the findings might rather be attributed to lifestyle factors and not directly to work conditions, but the excess risk of cancers of kidney and bladder, for example, might be related to work exposures.

Systematic review of genotoxicity induced by occupational exposure to antineoplastic drugs

With increasing numbers of cancer cases, the use of antineoplastic agents is expected to rise. This will be accompanied by an increase in occupational exposure, which can cause unwanted health effects in workers. Our aim was to give an overview of genotoxic and epigenetic effects after occupational exposure to antineoplastic agents and to assess the concentration-effect relation. Four databases were searched for papers investigating genotoxic and/or epigenetic effects of occupational exposure to antineoplastic agents. Out of the 245 retrieved papers, 62 were included in this review. In this systematic literature review, we confirmed that exposure of healthcare workers to antineoplastic agents can lead to genotoxic damage. However, we observed a lack of data on exposure as well as genotoxic and epigenetic effects in workers other than healthcare workers. Furthermore, gaps in the current knowledge regarding the potential epigenetic effects caused by antineoplastic drug exposure and regarding the link between internal antineoplastic drug concentration and genotoxic and epigenetic effects after occupational exposure to antineoplastic agents were identified, offering a first step for future research.

Ethical Challenges Posed by Advanced Veterinary Care in Companion Animal Veterinary Practice

Simple Summary

Veterinary care of companion animals, particularly dogs and cats, continues to advance, with some companion animals receiving a standard of care equal to or exceeding that of human patients. While this has the potential to improve animal welfare and benefit other stakeholders, including animal owners and veterinary team members, it also poses ethical challenges. We discuss key ethical challenges associated with AVC, including its relationship to standards of veterinary care, its potential to perpetuate poor quality of life and suffering, cost and accessibility of veterinary care, conflicts of interest, and concerns about experimentation without appropriate ethical review. We conclude by suggesting some strategies for veterinary teams and other stakeholders, such as professional bodies and regulators, to address these concerns.

Abstract

Advanced veterinary care (AVC) of companion animals may yield improved clinical outcomes, improved animal welfare, improved satisfaction of veterinary clients, improved satisfaction of veterinary team members, and increased practice profitability. However, it also raises ethical challenges. Yet, what counts as AVC is difficult to pinpoint due to continuing advancements. We discuss some of the challenges in defining advanced veterinary care (AVC), particularly in relation to a standard of care (SOC). We then review key ethical challenges associated with AVC that have been identified in the veterinary ethics literature, including poor quality of life, dysthanasia and caregiver burden, financial cost and accessibility of veterinary care, conflicts of interest, and the absence of ethical review for some patients undergoing AVC. We suggest some strategies to address these concerns, including prospective ethical review utilising ethical frameworks and decision-making tools, the setting of humane end points, the role of regulatory bodies in limiting acceptable procedures, and the normalisation of quality-of-life scoring. We also suggest a role for retrospective ethical review in the form of ethics rounds and clinical auditing. Our discussion reenforces the need for a spectrum of veterinary care for companion animals.

Occupational Safety in Chemosensitivity Tests: A Method to Minimize the Risk of Contamination While Maximizing the Safety for the Examiner

In vitro chemosensitivity tests are a widely used and established method in research. In laboratory environments, work safety is particularly important when working with carcinogenic, mutagenic, or reprotoxic (CMR) substances. When working with cell cultures, minimizing the risk of contamination with CMR substances and protecting the experimenter must be in the foreground of the experimental setup since risk minimization and occupational safety when handling CMR substances are mandatory. To minimize any personnel risk, studies with solid CMR substances should be carried out in a closed system. However, publications on occupational health and safety in laboratory environments in which CMR substances are tested in cell cultures are rare. Therefore, this article presents an easily applicable and safe method for improving work safety for in vitro chemosensitivity tests when working with CMR substances while also taking cell culture hygiene into account. For this purpose, a risk assessment of the test design was carried out, and the steps that were decisive for safety were highlighted. Some user-friendly and easily reproducible elements are presented, which increase the occupational safety of in vitro chemosensitivity assays, especially by reducing the risk of personnel contamination.

Veterinary Clinical Ethics and Patient Care Dilemmas

Veterinary ethical dilemmas are common, complex, and unavoidable. Creating a transparent and deliberate approach to ethical issues empowers the entire veterinary team and reduces stress associated with these dilemmas. This article discusses ethical considerations and principles and propose use of the 4Es model and core communication skills to address ethical dilemmas in veterinary practice. It reviews literature defining ethical issues in practice and provides case examples to show the application of our proposed methods. The goal is to provide veterinary professionals with an approach they can use to frame and address their own ethical decisions.

A novel bone marrow-sparing treatment for primary erythrocytosis in a cat: Onion powder

Primary erythrocytosis (PE) is a rare myeloproliferative neoplasm in cats resulting in the overproduction of erythrocytes. Current treatment modalities include repeated phlebotomy and chemotherapeutic drugs. These treatments may not be well tolerated by the cat and can present safety and financial challenges to owners. Because of the rarity of PE, prospective studies for new treatment options are difficult to perform. This case report describes the novel use of onion powder in an attempt to produce Heinz body‐induced erythrocyte destruction in order to decrease total erythrocyte mass and normalize the hematocrit in a cat with PE. To our knowledge, the use of onion powder in the treatment of PE in cats has never been described before and may have potential as a safe, low‐cost, and highly accessible alternative treatment for this rare disease.

ACVIM small animal consensus statement on safe use of cytotoxic chemotherapeutics in veterinary practice

The purpose of this report is to offer a consensus opinion of ACVIM oncology diplomates and technicians on the safe use of cytotoxic chemotherapeutics in veterinary practice. The focus is on minimizing harm to the personnel exposed to the drugs: veterinary practitioners, veterinary technicians, veterinary staff, and pet owners. The safety of the patient receiving these drugs is also of paramount importance, but is not addressed in this statement. Much of the information presented is based on national recommendations by Occupational Safety and Health Administration, National Institute for Occupational Safety and Health, United States Pharmacopeia, and other published regulations. These directives reflect an abundance of caution to minimize exposure to medical personnel, but large-scale studies about the consequences of long-term occupational exposure are not available in veterinary medicine. Challenges in the delivery of optimal treatment safely and economically to veterinary patients in general practice without access to a veterinary oncologist or other specialist, because of costs or proximity, remain.