Intralesional and topical chemotherapy and immunotherapy

Equine Melanoma Updates

Melanomas are very common in older gray horses, with 80% of gray horses having at least 1 melanoma by 15 years of age. Historically considered a benign disease, it is now known that up to 66% of lesions will eventually metastasize. Melanomas may also cause local problems due to abscessation, ulceration, and interference with function of the affected areas. Treatment can be limited by size and location, but surgical resection, where possible, is likely to be the treatment of choice.

Intralesional interferon alpha-2b as a novel treatment for periocular squamous cell carcinoma in horses

OBJECTIVE

To determine the safety and efficacy of perilesional human recombinant interferon alpha-2b (IFNα2b) for treatment of periocular squamous cell carcinoma (PSCC) in horses.

ANIMALS STUDIED

Eleven horses (12 eyes) with PSCC were enrolled in this prospective clinical study with owner consent.

PROCEDURES

Systemically healthy horses were included in the study following confirmation of PSCC via biopsy. Every two weeks for a maximum of six treatments, horses were sedated and perilesional injection of IFNα2b (10 million IU) was performed. Tumors were measured prior to each injection and at one, three, and 12 months after treatment completion. A greater than 50% reduction in tumor size was considered positive response to treatment (i.e., partial or complete response). Development of anti-IFNα2b antibodies was assessed using serum samples obtained after treatment initiation and compared with treatment responses. Antibody concentrations were analyzed using a mixed model. Statistical significance was considered p < 0.05.

RESULTS

Each horse received four to six perilesional injections of IFNα2b. Five of 12 eyes (4/11 horses) responded to treatment. Two of five eyes showed complete resolution of gross PSCC. No systemic adverse effects were seen. Local swelling occurred during treatment protocol in 6/11 horses but resolved without intervention. All horses developed serum anti-IFNα2b antibodies. There was no evidence of statistical difference in antibody concentration between responders and non-responders.

CONCLUSIONS

Perilesional administration of IFNα2b was found to be well-tolerated in horses with PSCC, and induced tumor regression in 42% of treated eyes. Treatment failure appears unrelated to the development of IFNα2b antibodies.

Interventions for treatment of cutaneous melanoma in horses: a structured literature review

Several therapies have been developed to treat equine cutaneous melanoma, but formal comparisons among different treatment options are currently unavailable. It was our intent to assess the efficacy of different treatment protocols and the quality of the studies based on the original published data, and summarize the knowledge concerning the outcome after equine cutaneous melanoma management. This structured review followed PRISMA procedure to search for treatment protocols on equine cutaneous melanoma published from 1960 until June 2021. Studies were assessed for the risk of bias. A descriptive analysis was performed, considering the disease control rate, the recurrence rate of the tumor, comorbidities, need for anesthesia, and horses' welfare. Twenty-three studies were included, from which the treatment outcomes of 173 horses were assessed. The homogeneity of the included trials was low. The percentages of each treatment arm achieving a partial response and curative effects accounted for 93.1% (surgical intervention), 90% (medication), and 39.4% (immunotherapies), respectively. A variable efficacy of different therapies of equine cutaneous melanoma was observed. Surgical intervention performed the best from the perspective of local antitumor effects alone. This literature review and descriptive analysis can serve as a source to assist in designing quality therapy research and can potentially aid in providing a clinical treatment reference for equine cutaneous melanoma.

Molecular characterization of equine thymidine kinase 1 and preliminary evaluation of its suitability as a serum biomarker for equine lymphoma

Background

Thymidine kinase 1 (TK1) plays a key role in the synthesis of deoxythymidine triphosphate (dTTP) and is thus important for DNA replication and cell proliferation. The expression of TK1 is highest during S-phase, and it is rapidly degraded after mitosis. In cancer cells, TK1 is upregulated, resulting in leakage of excess TK1 into the blood. Consequently, serum TK1 has been used as a diagnostic and prognostic cancer biomarker, mainly in human medicine. The aims of this work were to characterize equine TK1 and to evaluate its suitability as a serum biomarker for equine lymphoma.

Results

Equine TK1 was cloned, expressed in E. coli and affinity purified. The purified recombinant horse TK1 showed broad substrate specificity, phosphorylating pyrimidine deoxyribo- and ribonucleosides and, to some extent, purine deoxynucleosides, including anticancer and antiviral nucleoside analogues. ATP was the preferred phosphate donor. Serum TK1 activity was measured in samples collected from horses with confirmed or suspected lymphoma and control horses with and without concurrent diseases. Serum TK1 activity levels were significantly higher in horses with lymphoma (p <  0.0005) and suspected lymphoma (p <  0.02) and in tumour-free groups with diverse diseases (p <  0.03) than in controls without concurrent diseases. There was a significant difference between the lymphoma group and the tumour-free group with diverse diseases (p <  0.0006). Furthermore, receiver operating characteristic analysis revealed a sensitivity of 0.86, a specificity of 0.95 and an AUC (area under the curve) of 0.92 compared to the controls without concurrent diseases, with a sensitivity of 0.97, a specificity of 0.71 and an AUC of 0.88 when compared with the tumour-free group with diverse diseases.

Conclusion

Equine TK1 showed high specific activity and broader substrate specificity than human TK1. Anticancer and antiviral thymidine analogues were efficiently phosphorylated by horse TK1, suggesting that these analogues might be good candidates for chemotherapy in horses. Serum TK1 activity was significantly higher in horses with lymphoma than in controls. ROC analysis indicated that serum TK1 could serve as a promising cancer biomarker in horses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-021-00399-x.

How to overcome the side effects of tumor immunotherapy

The incidence of cancer is increasing year by year. Cancer has become one of the health threats of modern people. Simply relying on the surgery, chemotherapy or radiotherapy, not only the survival rate is not high, but also the quality of life of patients is not much better. Fortunately, the emergence and rapid development of cancer immunotherapy have brought more and more exciting results. However, when scientists think it is possible to overcome cancer, they find that not all cancer patients can benefit from immunotherapy, that is to say, the overall efficiency of immunotherapy is not high. Drug resistance and side effects of immunotherapy cannot be ignored. In order to overcome these difficulties, scientists continue to improve the strategy of immunotherapy and find that combination therapy can effectively reduce the incidence of drug resistance. They also found that by reprogramming tumor blood vessels, activating ferroptosis, utilizing thioredoxin, FATP2 and other substances, the therapeutic effect can be improved and side effects can be alleviated. This article reviews the principles of immunotherapy, new strategies to overcome drug resistance of cancer immunotherapy, and how to improve the efficacy of immunotherapy and reduce side effects.

Treatment Options for Melanoma of Gray Horses

All gray horses inherited a single gene mutation, STX17^G, that unbalances melanocyte behavior to cause graying and propensities to develop vitiligo and melanoma. The coat color genes ASIP^a and MC1R^E add risk such that relative likelihood of melanoma based on pregraying coat color is black > bay > chestnut. Melanomas begin at about 4 years. Locoregional control of melanoma masses depends on surgical removal and/or intralesional chemotherapy (possibly with adjunctive hyperthermia or electroporation). Systemic treatment is not evidence based but immunomodulators (cimetidine, levamisole) and vaccines can be tried.

Rabbit Oncology: Diseases, Diagnostics, and Therapeutics

Neoplasia has long been reported as a rare finding in rabbits, but over the past decades the number of reports on neoplastic disease in rabbits has risen considerably. Similar to other animals, neoplastic changes may occur in any organ system, but the rate in which the organ systems are affected differs considerably. In rabbits, tumors have predominantly been found in the urogenital, hemolymphatic, and integumentary systems. This article discusses current insights on the etiopathogenesis, clinical signs, diagnosis, and treatment of the commonest neoplastic diseases in rabbits and offer guidelines for the correct diagnosis and treatment of the rabbit oncologic patient.

Electrochemotherapy as a single or adjuvant treatment to surgery of cutaneous sarcoid tumours in horses: a 31-case retrospective study

The aim of our study was to evaluate the efficacy of electrochemotherapy (ECT) with cisplatin as a single or adjuvant treatment for sarcoids in equids. Different treatment options with different success rates were proposed. Thirty-one horses and one donkey with different clinical type, size and location of tumours were treated with ECT as a single treatment (18 animals with 52 tumour nodules) or as adjuvant treatment with marginal surgical excision (14 animals with 18 tumour nodules). In animals treated only with ECT with cisplatin, complete response was obtained in 48/52 (92.3 per cent) nodules and partial response in the other 4 nodules (7.7 per cent). In most cases, one to three sessions, only in two cases four and in one case five sessions, every 4 weeks were needed to obtain the measurable response. During the observation time, only in one case was the recurrence noted 60 months after treatment. Complete response in all 18 tumour nodules treated with surgery and adjuvant ECT was obtained and only one recurrence was noted after 14 months during the observation time. The results of this study show that ECT with cisplatin is an effective, safe, and simple local treatment of sarcoids in equids. According to the tumour size and location, single or combined treatment should be performed.

Equine sarcoids: Bovine Papillomavirus type 1 transformed fibroblasts are sensitive to cisplatin and UVB induced apoptosis and show aberrant expression of p53

Bovine papillomavirus type 1 infects not only cattle but also equids and is a causative factor in the pathogenesis of commonly occurring equine sarcoid tumours. Whilst treatment of sarcoids is notoriously difficult, cisplatin has been shown to be one of the most effective treatment strategies for sarcoids. In this study we show that in equine fibroblasts, BPV-1 sensitises cells to cisplatin-induced and UVB-induced apoptosis, a known cofactor for papillomavirus associated disease, however BPV-1 transformed fibroblasts show increased clonogenic survival, which may potentially limit the therapeutic effects of repeated cisplatin treatment. Furthermore we show that BPV-1 increases p53 expression in sarcoid cell lines and p53 expression can be either nuclear or cytoplasmic. The mechanism and clinical significance of increase/abnormal p53 expression remains to be established.

Optimization of a procedure to accurately detect equine TNFα in serum samples

The systemic component of chronic inflammatory diseases may lead to clinical complications. High levels of TNFα, a pro-inflammatory cytokine, are found in human patients with COPD and asthma. Horses are also susceptible to an array of chronic inflammatory disorders possibly associated with systemic inflammation, including respiratory diseases. Currently, there is no commercially available ELISA validated to assess TNFα in equine serum samples. Moreover, the reported normal mean concentration of serum TNFα in horses vary greatly. Hence, we sought to optimize and validate a procedure to quantify this cytokine in equine serum samples using a sandwich ELISA. Our results indicate that the nature of diluent buffers greatly impact the detection of TNFα in equine serum samples as its quantification increased in some cases from non-detectable levels to the ng/ml range. Linearity assays performed with serum samples from six animals serially diluted in four different buffers showed that serum matrix interference was animal-dependant. The specificity of TNFα detection was also assessed. Our optimized assay conditions were validated by quantifying levels of TNFα in serum samples from normal horses and horses affected with chronic pulmonary disease (heaves).

Long-term outcome associated with intratumoral chemotherapy with cisplatin for cutaneous tumors in equidae: 573 cases (1995–2004)

OBJECTIVE

To determine outcome associated with cutaneous tumors treated via intratumoral chemotherapy with cisplatin and identify risk factors affecting local tumor control and complications in equidae.

DESIGN

Retrospective case series.

ANIMALS

573 equidae with 630 cutaneous tumors.

PROCEDURES

Medical records of horses, mules, donkeys, and ponies with cutaneous tumors treated via intratumoral chemotherapy with cisplatin were analyzed.

RESULTS

549 horses, 13 mules, 8 donkeys, and 3 ponies with 630 histologically confirmed cutaneous tumors were included. Tumors included sarcoids (n = 409), squamous cell carcinomas (151), soft tissue sarcomas (28), cutaneous lymphomas (26), and melanomas (16). Overall cure rate, defined as local control at 4 years, was 93.3%. For all tumor stages combined, cure rates after 1 course of treatment were 96.3% for sarcoids, 96% for lymphomas, 88% for squamous cell carcinomas, 85% for soft tissue sarcomas, and 81% for melanomas. Treatment protocol, tumor stage, and prior treatment were significant prognostic factors for tumor control. Treatment efficacy was lower for large tumors, those with gross postoperative residual disease, and those that had been treated previously with other modalities. Treatment was well tolerated. Local reactions were more likely to occur and to be more severe after the third and fourth treatment sessions.

CONCLUSIONS AND CLINICAL RELEVANCE

Results confirmed the value of intratumoral chemotherapy with cisplatin for treatment of cutaneous tumors in equidae. The results cannot be extrapolated to other formulations of cisplatin or other protocols that might be used.

Current therapies in exotic animal oncology

The majority of information on oncology therapies has been reported in humans, canine, and feline patients, and laboratory animals with experimentally induced tumors. A variety of treatments,including radiation therapy, chemotherapy, photodynamic therapy, and others have been used with exotic animals. There are many species of exotic pets, and anatomic differences, as well as husbandry and nutritional requirements, must be taken into account to provide optimal care. By providing a broad overview of therapies and considerations for treatment, this article is intended to provide the practitioner with an overview of approach and options when addressing oncology cases in exotic animals.

Intratumoral cancer chemotherapy and immunotherapy: opportunities for nonsystemic preoperative drug delivery

The recent literature documents the growing interest in local intratumoral chemotherapy as well as systemic preoperative chemotherapy with evidence for improved outcomes using these therapeutic modalities. Nevertheless, with few exceptions, the conventional wisdom and standard of care for clinical and surgical oncology remains surgery followed by radiation and/or systemic chemotherapy, as deemed appropriate based on clinical findings. This, in spite of the fact that the toxicity of conventional systemic chemotherapy and immunotherapy affords limited effectiveness and frequently compromises the quality of life for patients. Indeed, with systemic chemotherapy, the oncologist (and the patient) often walks a fine line between attempting tumour remission with prolonged survival and damaging the patient's vital functions to the point of death. In this context, it has probably been obvious for more than 100 years, due in part to the pioneering work of Ehrlich (1878), that targeted or localized drug delivery should be a major goal of chemotherapy. However, there is still only limited clinical use of nonsystemic intratumoral chemotherapy for even those high mortality cancers which are characterized by well defined primary lesions i.e. breast, colorectal, lung, prostate, and skin. There has been a proliferation of intratumoral chemotherapy and immunotherapy research during the past two to three years. It is therefore the objective of this review to focus much more attention upon intratumoral therapeutic concepts which could limit adverse systemic events and which might combine clinically feasible methods for localized preoperative chemotherapy and/or immunotherapy with surgery. Since our review of intratumoral chemoimmunotherapy almost 20 years ago (McLaughlin & Goldberg 1983), there have been few comprehensive reviews of this field; only one of broad scope (Brincker 1993), three devoted specifically to gliomas (Tomita 1991; Walter et al. 1995; Haroun & Brem 2000), one on hepatomas (Venook 2000), one concerning veterinary applications (Theon 1998), and one older review of dermatological applications (Goette 1981). However, none have shed light on practical opportunities for combining intratumoral therapy with subsequent surgical resection. Given the state-of-the-art in clinical and surgical oncology, and the advances that have been made in intratumoral drug delivery, minimally invasive tumour access i.e. fine needle biopsy, new drugs and drug delivery systems, and preoperative chemotherapy, it is timely to present a review of studies which may suggest future opportunities for safer, more effective, and clinically practical non-systemic therapy.