Animal Models of Cancer Pain

Abstract

220Pain is one of the most common and distressing symptoms experienced by both human and veterinary oncology patients with advanced cancer. In humans, unrelieved pain can disrupt and interfere with activities of daily living, quality of life, and mood, 26,173 and domestic animals typically are euthanized when pain is no longer adequately controlled. 138 New developments in cancer detection and therapy have occurred over the past decade. These developments are contributing to longer life expectancies and have raised important issues related to quality of life, as attention has focused increasingly on how to manage cancer pain effectively. 91,115,134 This increased attention is true in the fields of both human and veterinary medicine. Human cancer patients who are in advanced stages of the disease, particularly those with bone metastasis, report that they experience significant pain, and pain intensity appears to be related to the degree of bone destruction. Similarly, pain secondary to cancer in domestic animals is a key concern in veterinary practice and should be addressed promptly to alleviate suffering, stress, and anxiety and to improve quality of life. Not only do cancer patients have to deal with persistent pain, they also often experience 'breakthrough pain.' Breakthrough pain-intermittent episodes of extreme pain-occurs spontaneously or after movement or weight-bearing of the affected leg. 114,133 Canine osteosarcoma has many clinical and biological similarities to human osteosarcoma, and affected dogs show signs of both ongoing and breakthrough pain. 37 In addition to cancer-induced pain, human patients also experience pain caused by the very therapies used to treat the cancer. Almost 30% of adult cancer patients and 60% of pediatric cancer patients who have undergone treatments that include radiation, chemotherapy, or surgery also have experienced pain resulting from these therapeutic procedures. 49,174 Whether radiation treatment and chemotherapy also induce pain in domestic animals is virtually impossible to address, because carefully controlled studies have not examined this issue.Pain intensity varies among cancer patients and is dependent on a patient's pain sensitivity, the type of cancer, and the tumor location. 48,49 Cancer treatment guidelines provided by the World Health Organization have been used in oncology and pain treatment clinics. 20,25,92,113,117,119,163 Treatment of human cancer patients include the use of opioids, nonsteroidal antiinflammatory drugs (NSAIDs), corticosteroids, local anesthetics, antidepressants, and anticonvulsants either alone or in combination. Similarly in veterinary medicine, the goal of palliative therapy in cancer patients is to control pain from an incurable tumor and to support overall quality of life. 165 Therefore, opioids, NSAIDs, and bisphosphonates are used in addition to surgery and radiation therapy and are the drugs of choice in treating domestic animals with cancer pain, particularly those suffering from osteosarcoma and other forms of bone cancer. 1...

The Study of Pain in Rats and Mice

“…However, not all cancer models are widely used as pain models. This review will touch on soft tissue and bone pain in 2 common models; an exhaustive review of cancer models 95,183,184 is beyond the scope of this work.…”

Expression of p53 Protein Associates with Anti-PD-L1 Treatment Response on Human-Derived Xenograft Model of GATA3/CR5/6-Negative Recurrent Nonmuscular Invasive Bladder Urothelial Carcinoma

“…A facial scale model was used to control the pain reaction in all experimental groups [ 40 , 41 ]. Moderate pain was controlled with 100 mg/kg twice daily of Ketoprofen (substance K1751, Merck Sigma-Aldrich, Darmstadt, Germany, purity > 98%) administered intragastrically via a curved feeding needle (Kent Scientific, Torrington, CT, USA) [ 42 , 43 ]. Animals suffering severe pain uncontrolled with painkillers were euthanized.…”

Neurobiological studies of chronic pain and analgesia: Rationale and refinements

“…These studies have enabled us to better model different types of cancers, to understand the impact of different types of cancers on bone (Lozano-Ondoua et al, 2013;Sabino et al, 2003), and to more closely represent the clinical experience. Neuropharmacological studies in these models have validated the effectiveness of opioid and alpha 2 adrenergic agonists (Wacnik et al, 2000), cannabinoid receptor analgesic agonists Lozano-Ondoua et al, 2013), osteoprotegerin (Honore et al, 2000), and anti-nerve growth factor antibodies (Jimenez-Andrade et al, 2011).…”