Cancer in veterinary patients is, unfortunately, a common occurrence. One in five cats and almost fifty percent of dogs over age ten develop cancer, and because it is often not diagnosed in its early stages, it carries a high mortality risk. However, advancements in veterinary oncology care are making it possible to detect cancer more quickly and treat it more effectively, improving patient outcomes.
Given the prevalence of cancer in animals, staying updated on these advancements enables primary care veterinarians to provide clients with the best treatment options for their pet’s needs.
Some of the most promising developments in veterinary oncology include:
- Improved diagnostics.
- Targeted drug therapy.
Traditional Diagnostic Imaging
For over 40 years, radiography and ultrasonography were routinely used to diagnose cancer in veterinary patients. These diagnostic imaging options were appealing to veterinary hospitals and clinics due to their comparative accessibility and low cost to operate. While these imaging techniques have some advantages, they are not extremely effective at detecting small, early-stage malignancies. As a result, veterinarians are making greater use of CT, MRI, and PET imaging modalities that can detect much smaller tumors and allow for improved tumor assessment capabilities using contrast agents. While these imaging techniques have a greater sensitivity for tumor detection, they are costly and require the use of anesthesia.
Liquid Biopsy Testing
Over the last several years, researchers have further developed their understanding of how changes in the genome cause cancer and a new “liquid biopsy” technique for detecting cancer has been developed. With liquid biopsy testing, a bodily fluid (usually blood, but urine, cerebrospinal fluid, or other secretions could be used) is obtained using a non-invasive or minimally invasive method. Most commonly, the sample is then analyzed to calculate the level of circulating tumor DNA (ctDNA)—which originates from cancer cells—that is present in the broader pool of cell-free DNA (cfDNA)—which is created due to normal cellular turnover. The presence of ctDNA is indicative of cancer, and further testing is then needed to provide a definitive diagnosis and determine the stage of the cancer. Liquid biopsy testing can be useful in all phases of cancer care, including:
- Screening for early detection, especially in high-risk patients.
- Assisting in the diagnosis process, particularly for tumors in difficult-to-access locations and tumors with an unknown location.
- Choosing targeted therapeutics for treatment.
- Checking treatment effectiveness.
- Monitoring for relapse.
Liquid biopsy testing is still being perfected, with developers focusing on improving test sensitivity to ensure cancer cases are accurately identified. In 2022, the CANcer Detection in Dogs (CANDiD) study, which included 1,100 dogs from 41 clinical sites worldwide, studied the sensitivity of liquid biopsy testing and found that it accurately detected:
- 85% of lymphoma, hemangiosarcoma, and osteosarcoma cases, which are the most aggressive of cancers found in dogs.
- 62% of the eight most common canine cancers—lymphoma, hemangiosarcoma, osteosarcoma, mast cell tumor, mammary gland carcinoma, soft tissue sarcoma, anal sac adenocarcinoma, and malignant melanoma.
- 55% for the twenty-two other cancers included in the study.
Liquid biopsy testing will not replace diagnostic imaging or solid biopsies, which require obtaining a portion of the tumor for testing but will complement them. In the future, liquid biopsy may enable veterinarians to detect cancer at the beginning stage of progression before changes are identifiable using diagnostic imaging, and it could play an important role in conducting multi-cancer early detection screens regularly in animals at high-risk for cancer, such as older dogs and breeds predisposed to cancer. Liquid biopsy testing is helpful for cases where a tumor sample is difficult to obtain and can also augment the information obtained from a solid biopsy. Tumors frequently contain cells with variations in genetic mutations both within separate sites of the same tumor and across tumors in different locations, and a liquid biopsy can detect this “tumor heterogeneity” more effectively than a solid biopsy. As a result, liquid biopsy testing will play a key role in providing patients with a personalized approach to treatment with targeted therapeutics.
Precision medicine, also referred to as personalized medicine, is shaping the trajectory of modern medicine, including veterinary oncology. With precision medicine, cancer biomarkers, including genes and proteins, are tested to provide critical information about a patient’s cancer. As a result, treatments are targeted to meet the patient’s unique needs, resulting in improved outcomes. For example, the analysis of the DNA of malignant tumors is advancing cancer management. Tumor profiling can be helpful in:
- Providing accurate diagnostic assessments.
- Making informed prognostic assessments.
- Guiding treatment plan development.
- Monitoring treatment effectiveness.
Biomarker testing is important in cancer care because the genetic mutations found in a cancerous tumor can vary significantly between patients, even if they have the same type of cancer. Additionally, the genetic mutations found within a particular tumor can change over time, and different tumors within the same patient may have different genetic mutations. These gene mutation variations can significantly impact standard cancer therapies’ effectiveness.
With tumor profiling, a core biopsy is done to obtain a tumor tissue sample. DNA from the tissue is then extracted and sequenced to identify the gene mutations present and to determine the proteins produced as a result of those specific mutations. The proteins driving the tumor’s growth can then be targeted with treatment options, including targeted drug therapy and immunotherapy. So, instead of killing all cells in the body that are growing and dividing rapidly as occurs with traditional chemotherapy, most targeted therapy attack only the proteins helping the tumor to grow and spread.
Personalized care throughout the treatment process
We know side effects of chemotherapy treatment can be difficult for your patients and their owners. To help you provide tailored care to your patients throughout their treatment process, a new commercial drug, Canalevia, a non-antimicrobial option for the treatment of chemo-therapy induced diarrhea is available to veterinarians through authorized distributors and for individual patient prescriptions through Stokes Pharmacy. Epicur also continues to manufacture the well-known, Metronidazole which is available for office use and also individual patient prescriptions through Stokes Pharmacy.
Using targeted therapeutics based on tumor profiling is an emerging technique, but it shows a lot of promise in improving cancer care. With targeted therapeutics, treatment options that will impede molecular pathways key to tumor growth and maintenance are selected based on a patient’s genetic profile. Currently, genomic analysis of malignant tissue can identify hundreds of genes within a tumor’s DNA; however, targeted therapies have only been developed for a small portion of those genes. In veterinary medicine only two targeted therapies have been FDA approved for use:
- Laverdia® (verdinexor)—Conditionally approved to treat lymphoma, the most common canine cancer. Available as an oral tablet.
- Palladia® (toceranib phosphate)—Administered orally to treat several types of canine cancers, including mast cell tumors and thyroid carcinomas, among many others.
Given the strong interest in precision medicine in both academia and industry, the number of targeted therapies available is expected to rapidly increase in the coming years.
With immunotherapy, targeted treatments are implemented that use a patient’s own immune system to fight cancer. Three main types of immunotherapies that are undergoing rigorous development include:
- Adoptive cell therapy (ACT)—Cells from the patient or a donor are genetically modified or trained using other techniques and transferred into a patient to combat cancer cells.
- Systemic immunomodulators—Immunomodulators include checkpoint inhibitors (block immune checkpoints so tumors are not able to shut down immune responses), agonists (boost adaptive immune response), adjuvants (promote general immune response), and cytokines (regulate immune cells).
- Cancer vaccines—Cancer vaccines train the immune system to identify specific proteins produced by a tumor. Oncept®, used to treat canine melanoma, is an example.
Great strides are being made in veterinary oncology. While traditional treatment options like surgery, radiation, and chemotherapy are well tolerated in animal patients, the survival times achieved with these options alone have likely reached their limits. Cancer detection at earlier stages combined with personalized treatments targeted to each patient’s unique needs are making it possible for patients to experience longer, higher quality lives after a cancer diagnosis.
Epicur specializes in manufacturing chemotherapy tablets that are tested for potency and endotoxins following FDA regulations and are available in unit-dose blister packs for safe handling.
Contact us today to place your order.
- Optimizing Novel Immunotherapy Combinations Targeting the Tumor Microenvironment in Canine Spontaneous Osteosarcoma https://vet.tufts.edu/clinical-trials/optimizing-novel-immunotherapy-combinations-targeting-tumor-microenvironment-canine-spontaneous-osteosarcoma
- Systemic cellular viroimmunotherapy for canine high-grade gliomas https://jitc.bmj.com/content/10/12/e005669
- Targeted Therapy https://www.animalcancercentermonterey.com/targeted-therapy
- Targeted Therapies in Veterinary Oncology https://www.researchgate.net/publication/344739756_Targeted_Therapies_in_Veterinary_Oncology
- Immunotherapy Biomarkers https://www.cancerresearch.org/biomarkers-in-cancer-immunotherapy
- Biomarker Tests and Cancer Treatment https://www.cancer.org/cancer/diagnosis-staging/tests/biomarker-tests.html
- Precision or Personalized Medicine https://www.cancer.org/cancer/managing-cancer/treatment-types/precision-medicine.html
- Advances in the detection, characterization, and monitoring of cancer in pets https://www.dvm360.com/view/advances-in-the-detection-characterization-and-monitoring-of-cancer-in-pets
- Cancer Screening & “Liquid Biopsy” – What You Need to Know https://drandyroark.com/liquid-biopsy/
- Cancer detection in clinical practice and using blood-based liquid biopsy: A retrospective audit of over 350 dogs https://pubmed.ncbi.nlm.nih.gov/36661398/
- Current and future opportunities for liquid biopsy of circulating biomarkers to aid in early cancer detection https://jcmtjournal.com/article/view/4996
- Liquid biopsy: advantages, limitations, and outlook https://www.ogt.com/about-us/ogt-blog/liquid-biopsy-advantages-limitations-and-outlook/