Metronomic Therapy with Cyclophosphamide and Piroxicam Effectively Delays Tumor Recurrence in Dogs with Incompletely Resected Soft Tissue Sarcomas

Multimodal Blockade of the Renin-Angiotensin System in the Treatment of Cancer in Dogs Has Mild Adverse Effects in Some Dogs

The renin-angiotensin system (RAS) is increasingly being recognized to play a role in the tumor microenvironment, promoting tumor growth. Studies blocking a single part of the RAS have shown mixed results, possibly due to the existence of different bypass pathways and redundancy within the RAS. As such, multimodal blockade of the RAS has been developed to exert more complete inhibition of the RAS. The aim of the present study was to assess the safety of multimodal RAS blockade in dogs. Five dogs (four with appendicular osteosarcoma, one with oral malignant melanoma) were treated with atenolol, benazepril, curcumin, meloxicam, and metformin. The dogs underwent clinical examination, blood pressure measurement, and hematology and serum biochemistry tests performed at 0, 1, 3, 6, 9, and 12 weeks, then every 3 months thereafter. End-of-life decisions were made by the owners. None of the dogs developed hypotension. One dog had intermittent vomiting during the 64 weeks it was on the trial. One dog had a one-off increase in serum SDMA(symmetrical dimethylarginine) concentration. Dogs were euthanized at weeks 3 (osteosarcoma), 10 (osteosarcoma), 17 (osteosarcoma), and 26 (oral malignant melanoma), and one dog was still alive at the end of the trial at 64 weeks (osteosarcoma). This is the first assessment of multimodal blockade of the RAS in dogs, and the results suggest it causes only mild adverse effects in some animals. The efficacy of the treatment was not assessed due to the small number of dogs. This pilot study allows for future larger studies assessing multimodal RAS blockade for the treatment of canine cancer.

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.

Canine Mammary Tumors: Classification, Biomarkers, Traditional and Personalized Therapies

In recent years, many studies have focused their attention on the dog as a proper animal model for human cancer. In dogs, mammary tumors develop spontaneously, involving a complex interplay between tumor cells and the immune system and revealing several molecular and clinical similarities to human breast cancer. In this review, we summarized the major features of canine mammary tumor, risk factors, and the most important biomarkers used for diagnosis and treatment. Traditional therapy of mammary tumors in dogs includes surgery, which is the first choice, followed by chemotherapy, radiotherapy, or hormonal therapy. However, these therapeutic strategies may not always be sufficient on their own; advancements in understanding cancer mechanisms and the development of innovative treatments offer hope for improved outcomes for oncologic patients. There is still a growing interest in the use of personalized medicine, which should play an irreplaceable role in the research not only in human cancer therapy, but also in veterinary oncology. Moreover, immunotherapy may represent a novel and promising therapeutic option in canine mammary cancers. The study of novel therapeutic approaches is essential for future research in both human and veterinary oncology.

Naturally occurring canine sarcomas: Bridging the gap from mouse models to human patients through cross-disciplinary research partnerships

Fueled by support from the National Cancer Institute's "Cancer Moonshot" program, the past few years have witnessed a renewed interest in the canine spontaneous cancer model as an invaluable resource in translational oncology research. Increasingly, there is awareness that pet dogs with cancer provide an accessible bridge to improving the efficiency of cancer drug discovery and clinical therapeutic development. Canine tumors share many biological, genetic, and histologic features with their human tumor counterparts, and most importantly, retain the complexities of naturally occurring drug resistance, metastasis, and tumor-host immune interactions, all of which are difficult to recapitulate in induced or genetically engineered murine tumor models. The utility of canine models has been particularly apparent in sarcoma research, where the increased incidence of sarcomas in dogs as compared to people has facilitated comparative research resulting in treatment advances benefitting both species. Although there is an increasing awareness of the advantages in using spontaneous canine sarcoma models for research, these models remain underutilized, in part due to a lack of more permanent institutional and cross-institutional infrastructure to support partnerships between veterinary and human clinician-scientists. In this review, we provide an updated overview of historical and current applications of spontaneously occurring canine tumor models in sarcoma research, with particular attention to knowledge gaps, limitations, and growth opportunities within these applications. Furthermore, we propose considerations for working within existing veterinary translational and comparative oncology research infrastructures to maximize the benefit of partnerships between veterinary and human biomedical researchers within and across institutions to improve the utility and application of spontaneous canine sarcomas in translational oncology research.

Insight into the Prospects for Tumor Therapy Based on Photodynamic Immunotherapy

Malignancy is one of the common diseases with high mortality worldwide and the most important obstacle to improving the overall life expectancy of the population in the 21st century. Currently, single or combined treatments, including surgery, chemotherapy, and radiotherapy, are still the mainstream regimens for tumor treatment, but they all present significant side effects on normal tissues and organs, such as organ hypofunction, energy metabolism disorders, and various concurrent diseases. Based on this, theranostic measures for the highly selective killing of tumor cells have always been a hot area in cancer-related fields, among which photodynamic therapy (PDT) is expected to be an ideal candidate for practical clinical application due to its precise targeting and excellent safety performance, so-called PDT refers to a therapeutic method mainly composed of photosensitizers (PSs), laser light, and reactive oxygen species (ROS). Photoimmunotherapy (PIT), a combination of PDT and immunotherapy, can induce systemic antitumor immune responses and inhibit continuing growth and distant metastasis of residual tumor cells, demonstrating a promising application prospect. This article reviews the types of immune responses that occur in the host after PDT treatment, including innate and adaptive immunity. To further help PIT-related drugs improve their pharmacokinetic properties and bioavailability, we highlight the potential improvement of photodynamic immunotherapy from three aspects: immunostimulatory agents, tumor-associated antigens (TAAs) as well as different immune cells. Finally, we focus on recent advances in various strategies and shed light on their corresponding mechanisms of immune activation and possible clinical applications such as cancer vaccines. Having discovered the inherent potential of PDT and the mechanisms that PDT triggers host immune responses, a variety of immunotherapeutic strategies have been investigated in parallel with approaches to improve PDT efficiency. However, it remains to be further elucidated under what conditions the immune effect induced by PDT can achieve tumor immunosuppression and to what extent PDT-induced antitumor immunity will lead to complete tumor rejection. Currently, PIT presents several outstanding intractable challenges, such as the aggregation ability of PSs locally in tumors, deep tissue penetration ability of laser light, immune escape, and biological toxicity, and it is hoped that these issues raised will help to point out the direction of preclinical research on PIT and accelerate its transition to clinical practice.

Metronomic Chemotherapy for Palliative Treatment of Malignant Oral Tumors in Dogs

The aim of this study was to evaluate the efficacy of metronomic chemotherapy in the palliative treatment of various malignant oral tumors in dogs. Our focus was to determine the effect of treatment on local disease control and to assess the tolerability and safety of the treatment in dogs with various oral malignancies. Metronomic chemotherapy with cyclophosphamide was used to treat 12 dogs and was combined with non-steroidal anti-inflammatory drugs in 6/12 (50%) of dogs. A clinical benefit was observed in 6/12 (50%) patients 1 month and in 4/12 (33%) 3 months after treatment initiation. The median survival time of the dogs was 155 days (range 21–529 days). At the end of the observation period, the disease had progressed in 10/12 (83.3%) of the patients. Sterile hemorrhagic cystitis was the most commonly reported side effect of treatment, occurring in 4/12 (33.3%) dogs. The results of our study suggest that metronomic chemotherapy with cyclophosphamide can be, in a subset of dogs, beneficial in the palliation of malignant oral tumors.

Procarbazine, prednisolone and cyclophosphamide (PPC) oral combination chemotherapy protocol for canine lymphoma

Orally administered daily chemotherapy offers a novel treatment approach for canine lymphoma in a population of dogs that have failed or not tolerated maximum tolerable dose chemotherapy. A multidrug oral chemotherapy protocol was designed and implemented for the treatment of fifty dogs with multicentric lymphoma with minimal side effects. The protocol consisted of oral procarbazine, prednisolone and cyclophosphamide (PPC) administered daily. Efficacy and toxicity were evaluated by clinical and laboratory evaluation. An overall response rate of 70% was achieved, with 24% and 46% of dogs having a partial and complete response, respectively, to treatment with the PPC protocol. Response to the PPC protocol (complete or partial) and age were the only factors identified as prognostic for time from initiation of the PPC chemotherapy until death. Overall, the protocol was very well tolerated with only one dog requiring protocol discontinuation due to grade 4 thrombocytopenia. Eight dogs recorded gastrointestinal toxicities, seven grade I and one grade II toxicity. These findings demonstrate that the administration of a continuous oral combination chemotherapy can provide comparable survival times in the rescue setting in dogs with multicentric lymphoma with minimal side effects.

Salivary proteomics in monitoring the therapeutic response of canine oral melanoma

Saliva biomarkers are suitable for monitoring the therapeutic response of canine oral melanoma (COM), because saliva directly contacts the tumor, and saliva collection is non-invasive, convenient and cost effective. The present study aimed to investigate novel biomarkers from the salivary proteome of COM treated with surgery and a chemotherapy drug, carboplatin, 1-6 times, using a liquid chromatography-tandem mass spectrometry approach. The expression of a potential salivary biomarker, ubiquitin D (UBD), was observed and verified by western blot analysis. A significantly increased ratio of free UBD (fUBD) to conjugated UBD (cUBD) was shown in the pre-surgery stage (PreS) in OM dogs with short-term survival (STS) (less than 12 months after surgery) compared with that with long-term survival (more than 12 months after surgery). In dogs with STS, the ratio was also shown to be augmented in PreS compared with that after surgery, followed by treatment with carboplatin twice, 4 and 5 times [After treatment (AT)2, AT4 and AT5]. In addition, the expression of fUBD was enhanced in PreS compared with that of AT2 in the STS group. In conclusion, this study revealed that a ratio of fUBD to cUBD in PreS was plausibly shown to be a potential prognostic biomarker for survival in dogs with OM.

Clinical outcome of dogs diagnosed with canine inflammatory mammary cancer treated with metronomic cyclophosphamide, a cyclooxygenase-2 inhibitor and toceranib phosphate

Canine inflammatory mammary cancer (IMC) is highly malignant, invasive and a therapeutic challenge, because effective medical treatment is still unavailable. This retrospective study compares the efficacy of an oral cyclooxygenase-2 (COX-2) inhibitor combined with toceranib phosphate and oral cyclophosphamide (multi-drug therapy [MT]) with COX-2 inhibitor therapy alone (single-drug therapy [ST]) in dogs diagnosed with secondary IMC. Clinical response, adverse events, overall survival time (OST), disease-free survival (DFS) and time to progression (TTP) were evaluated. Sixteen patients were included, eight received MT and eight receiving ST. Median OST was significantly higher in patients receiving MT (96.0 vs. 37.5 days; p = .046) and in patients with post-surgical rather than non-surgical IMC (86.5 vs. 41.5 days; p = .038). Additionally, median TTP was significantly higher in patients treated with MT (p = .010). In patients with non-surgical IMC, the clinical benefit (CB) was reached in 100% (n = 3) of patients receiving MT and in 33% (n = 1) of those receiving ST; the response duration was significantly longer in MT cases (p = .026). The absence of disease progression at day 30 of treatment was significantly associated with longer OST, DFS and TTP (p = .018, p = .002 and p < .001, respectively). Adverse events occurred more frequently in patients treated with MT compared with ST (p = .026). The MT protocol produced primarily mild to moderate toxicities, which were resolved with supportive care; therefore, the combination of drugs was adequately tolerated by most of the patients. The combination of toceranib, a COX-2 inhibitor and oral cyclophosphamide may be a protocol with potential therapeutic efficacy for dogs with IMC.

Surgical Margins in Canine Cutaneous Soft-Tissue Sarcomas: A Dichotomous Classification System Does Not Accurately Predict the Risk of Local Recurrence

Simple Summary

Histological evaluation of surgical margins is crucial for correct prognostication and adjuvant treatment recommendation after excision of soft tissue sarcoma (STS) in dogs. Incompletely excised STS have a high risk of local recurrence (LR), while completely excised STS without other negative prognostic factors are generally associated with a good prognosis. However, guidelines are lacking on how to manage STS excised with clean but close margins (CbCM), although some authors advocated their inclusion in the tumor-free margin group. This retrospective study investigates the impact of CbCM on LR of canine STS. Ninety-eight surgical excised canine STS at first presentation were included. Cumulative incidence of LR was estimated for each category of margins (tumor-free, infiltrated, CbCM), and after grouping CbCM alternatively in the tumor-free and infiltrated category. Cumulative incidence of LR at three years differed significantly between the three categories, and it was estimated to be 42% with infiltrated margins, 23% with CbCM, 7% with tumor-free margins. Both when CbCM were grouped with infiltrated margins or with tumor-free margins, the incidence of LR was statistically different. The rate of LR with CbCm was greater than with tumor-free margins. The category CbCM may be considered as a separate prognostic category.

Abstract

Adjuvant treatments are recommended in dogs with incompletely excised cutaneous soft-tissue sarcoma (STS) to reduce the risk of local recurrence (LR), although guidelines are lacking on how to manage clean but close margins (CbCM). This retrospective study investigates the impact of CbCM on LR of canine STS. Ninety-eight surgically excised canine STS at first presentation were included. Tissue samples were routinely trimmed and analyzed. Cumulative incidence of LR was estimated for each category of margins (tumor-free, infiltrated, CbCM), and included CbCM in the tumor-free and infiltrated category, respectively. The prognostic impact on LR was then adjusted for relevant prognostic factors. Cumulative incidence of LR at three years differed significantly between the three categories (p = 0.016), and was estimated to be 42% with infiltrated margins, 23% with CbCM, 7% with tumor-free margins. Both when CbCM were grouped with infiltrated margins (p = 0.033; HR = 5.05), and when CbCM were grouped with tumor-free margins (p = 0.011; HR = 3.13), a significant difference between groups was found. STS excised with infiltrated margins had the greatest risk of LR. The rate of LR with CbCm was greater than recurrence rate of tumor-free margins. The category CbCM may be considered as a separate prognostic category.

Prostatic leiomyosarcoma in a dog treated using a multimodal approach

Prostatic leiomyosarcoma is an uncommon tumor encountered in male dogs, with only 2 cases reported in the veterinary literature with no follow-up described. A 12-year-old male intact German Wirehaired Pointer presented for evaluation of straining to defecate and urinate. Whole body computed tomography (CT) examination identified a spherical multicavitary expansile mass arising from the prostate gland and severely obliterating the pelvic canal. Partial subcapsular prostatectomy was performed, and histological and immunohistochemical results were consistent with prostatic leiomyosarcoma. Metronomic cyclophosphamide and nonsteroidal anti-inflammatory drugs were administered as adjuvant chemotherapy. Follow-up CT 10 months later indicated no signs of recurrence or metastasis. To the best of our knowledge, this patient represents the first report of successful multidisciplinary treatment consisting of partial subcapsular prostatectomy and adjuvant chemotherapy for prostatic leiomyosarcoma in a dog. After 15 months of follow-up, the patient remained recurrence-free without metastasis.

From Conventional to Precision Therapy in Canine Mammary Cancer: A Comprehensive Review

Canine mammary tumors (CMTs) are the most common neoplasm in intact female dogs. Canine mammary cancer (CMC) represents 50% of CMTs, and besides surgery, which is the elective treatment, additional targeted and non-targeted therapies could offer benefits in terms of survival to these patients. Also, CMC is considered a good spontaneous intermediate animal model for the research of human breast cancer (HBC), and therefore, the study of new treatments for CMC is a promising field in comparative oncology. Dogs with CMC have a comparable disease, an intact immune system, and a much shorter life span, which allows the achievement of results in a relatively short time. Besides conventional chemotherapy, innovative therapies have a large niche of opportunities. In this article, a comprehensive review of the current research in adjuvant therapies for CMC is conducted to gather available information and evaluate the perspectives. Firstly, updates are provided on the clinical-pathological approach and the use of conventional therapies, to delve later into precision therapies against therapeutic targets such as hormone receptors, tyrosine kinase receptors, p53 tumor suppressor gene, cyclooxygenases, the signaling pathways involved in epithelial-mesenchymal transition, and immunotherapy in different approaches. A comparison of the different investigations on targeted therapies in HBC is also carried out. In the last years, the increasing number of basic research studies of new promising therapeutic agents on CMC cell lines and CMC mouse xenografts is outstanding. As the main conclusion of this review, the lack of effort to bring the in vitro studies into the field of applied clinical research emerges. There is a great need for well-planned large prospective randomized clinical trials in dogs with CMC to obtain valid results for both species, humans and dogs, on the use of new therapies. Following the One Health concept, human and veterinary oncology will have to join forces to take advantage of both the economic and technological resources that are invested in HBC research, together with the innumerable advantages of dogs with CMC as a spontaneous animal model.

Huge myxosarcoma arising from the greater omentum in a dog

A 13-year-old intact Pomeranian bitch presented with a 2-month history of abdominal distension and anorexia. Ultrasonography and computed tomography revealed a large tumor in the abdominal cavity without metastases. The tumor was surgically resected and histopathologically characterized by spindle-shaped to atypical-shaped neoplastic cells with basophilic stroma in the omental adipose tissue. Immunohistochemistry revealed that the neoplastic cells were positive for vimentin but negative for cytokeratin, S-100 protein, and α-SMA. The bitch was diagnosed as a myxosarcoma arising from the greater omentum. Postoperatively, metronomic chemotherapy with cyclophosphamide and piroxicam was initiated. The tumor recurred on postoperative day 49. Although the bitch died 102 days after the initial examination, her general condition was maintained until death.

Prognostic impact of clinical, haematological, and histopathological variables in 102 canine cutaneous perivascular wall tumours

Identification of prognostic factors for perivascular wall tumours (PWTs) is desirable to accurately predict prognosis and guide treatment. 100 and two dogs with surgically excised PWTs without distant metastasis were retrospectively enrolled in this multi-institutional study, and the impact of pre-treatment leukocyte parameters, clinical and histopathological variables on local recurrence (LR) and overall-survival time (OST) were evaluated. Increasing values of white blood cell count (WBCC), neutrophil count (NC) and neutrophil-to-lymphocyte ratio (NLR) were significantly correlated with the hazard of LR in univariate analysis. WBCC and NC remained prognostic when adjusted for margins, grade, tumour size, location and skin ulceration, but lost their significance when adjusted for mitotic index and necrosis, whilst NLR remained prognostic only when close margins where categorised as infiltrated. Castrated males had a higher hazard of LR than intact males in univariate analysis, but significance was lost in multivariate models. Ulcerated PWTs and those located on the distal extremities had a higher hazard of LR both in univariate and multivariate analysis. Histological grade, necrosis, mitotic count, and infiltrated margins were all associated with LR both in univariate and multivariate analysis. Boxer breed, older age, ulceration, grade III, necrosis >50% and higher mitotic count were correlated with shorter OST, although breed and age lost their significance in multivariate analysis. Prognostication of surgically excised PWTs should be based on both clinical and histopathological variables. If validated in further studies, leukocyte counts and NLR may aid the clinician in identifying dogs at higher risk of LR before treatment.

A combined protocol with piroxicam, chemotherapy, and whole pelvic irradiation with simultaneous boost volumetric modulated arc radiotherapy for muscle-invasive canine urinary transitional cell carcinoma: First clinical experience

The aims of this pilot study were to evaluate the feasibility and efficacy of high-dose hypofractionated volumetric modulated arc radiotherapy (VMAT) applied to whole pelvic region radiotherapy (WPRT) with multilevel simultaneous integrated boost (MLSIB) combined with piroxicam and chemotherapy for the treatment of canine transitional cell carcinoma (TCC) of the lower urinary tract with muscle invasion TCC. Twelve dogs were enrolled, according to stage, in two groups: group 1, TCC confined to the urinary tract; group 2, TCC with metastasis. The planning target volume dose was tailored from 36 to 42 Gy in 6 fractions. All dogs were prescribed piroxicam and radiosensitizing carboplatin, and six received chemotherapy after radiotherapy. Serial follow-ups with computed tomography and magnetic resonance imaging were performed. Disease control and toxicity effects were evaluated according to the Response Evaluation Criteria in Solid Tumors and Veterinary Radiation Therapy Oncology Group criteria. The treatment was well tolerated, and no high-grade side effects were reported. The median overall survival times for groups 1 and 2 were 1,230 and 150 days, respectively. A considerable percentage of patients in group1 (50%) were still alive at the time of writing this paper, and a longer follow-up could enable a more accurate survival analysis. This preliminary analysis shows that VMAT applied to the WPRT with MLSIB is an effective and safe option for dogs with lower urinary TCC, although the presence of metastases worsens the prognosis.

Sorafenib for the Treatment of Unresectable Hepatocellular Carcinoma: Preliminary Toxicity and Activity Data in Dogs

Unresectable nodular and diffuse hepatocellular carcinoma (HCC) have a poor prognosis with limited treatment options. Systemic traditional chemotherapy has been only rarely reported, with unsatisfactory results. The aim of this prospective, non-randomized, non-blinded, single center clinical trial was to investigate safety profile, objective response rate, time to progression and overall survival of sorafenib in comparison with metronomic chemotherapy (MC) consisting of thalidomide, piroxicam and cyclophosphamide in dogs with advanced, unresectable HCC. Between December 2011 and June 2017, 13 dogs were enrolled: seven received sorafenib, and six were treated with MC. Median time to progression was 363 days (95% CI, 191–535) in dogs treated with sorafenib versus 27 days (95% CI, 0–68) in dogs treated with MC (p = 0.044). Median overall survival was 361 days (95% CI, 0–909) in dogs receiving sorafenib, while 32 days (95% CI, 0–235) in those receiving MC (p = 0.079). Sorafenib seems to be a good candidate for the treatment of dogs with advanced HCC, due to a benefit in disease control and an acceptable safety profile, offering a good basis on which new randomized prospective clinical trials should be undertaken to compare the efficacy and drawback of sorafenib versus MC or traditional chemotherapy.

Panax ginseng is superior to vitamin E as a hepatoprotector against cyclophosphamide-induced liver damage

BACKGROUND AND AIMS

Cyclophosphamide (CPh) is a frequently used drug, in human and animals for its immunosuppressive and anticancer potential. However, it is metabolized by the liver yielding damaging toxicants (to the liver itself and other non-target vital organs) via oxidative stress, apoptosis induction and finally necrosis. Since there is no escaping of using such harmful medications, we focused on alleviating its side-effects. Panax ginseng Meyer is a potent candidate, and we still lack adequate information on its hepatoprotective role against cyclophosphamide-induced liver-damage.

METHODS

Here, we used P. ginseng (Korean Red Ginseng) compared to vitamin-E (natural antioxidant) in combating CPh-induced liver damage. Forty-eight albino rats were divided into 6 groups, Control, Ginseng, Vitamin E, Cyclophosphamide (CPh), CPh + Ginseng or CPh + Vitamin-E. Blood samples were taken for biochemical analyses and liver samples were collected for histopathology, oxidative stress evaluation, and gene expression analyses.

RESULTS

In CPh group, typical CPh-liver damage was evident (higher levels of AST, ALT, ALP; lower albumin and total proteins levels; lower liver tissue concentrations of SOD, GPX and CAT and higher MDA; injured liver histopathological picture; and finally increased TNF-α, IL-1β and Caspase3 and decreased BCL-2 genes expression). All these were abolished with either P. ginseng or vitamin-E administration. However, P. ginseng was overall superior to vitamin-E, especially in restoring blood biochemical findings and damaged histopathological picture.

CONCLUSIONS

Therefore, P. ginseng is a potent hepatoprotector (vitamin-E to a lesser extent) and should be considered where liver damage is expected secondary to damaging medications; as cyclophosphamide.

Salivary proteomics of canine oral tumors using MALDI-TOF mass spectrometry and LC-tandem mass spectrometry

Canine oral tumors are relatively common neoplasms in dogs. For disease monitoring and early diagnosis, salivary biomarkers are appropriate because saliva collection is non-invasive and requires no professional skills. In the era of omics, matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry (MALDI-TOF MS) coupled with liquid chromatography-tandem MS (LC-MS/MS) are suitable to identify potential disease-associated peptides and proteins. The present study aimed to use MALDI-TOF MS and LC-MS/MS to search for particular peptide mass fingerprints (PMFs) and conceivable biomarkers in saliva of dogs with early- and late-stage oral melanoma (EOM and LOM, respectively), oral squamous cell carcinoma (OSCC), benign oral tumors (BN), and periodontitis and healthy controls (CP). Pooled saliva samples in each group were used to be representative of population change. Unique PMFs were obtained and specific peptide fragments were sequenced by LC-MS/MS and BLAST-searched with mammalian protein databases. Seven peptide fragments appeared in the tumor groups (EOM, LOM, OSCC and BN) at 1096, 1208, 1322, 1794, 1864, 2354 and 2483 Da, two peptide fragments appeared in the LOM and OSCC groups at 2450 and 3492 Da, and in the CP controls at 2544 and 3026 Da. Also, protein–chemotherapy drug interaction networks were exhibited. Using western blot analysis, the expression of sentrin-specific protease 7 (SENP7), a peptide fragment at 1096 Da, in OSCC was significantly increased, as was the expression of TLR4, a peptide fragment at 3492 Da, in LOM and OSCC, compared with the CP group. The expression of nuclear factor kappa B (NF-κB), a TLR4 partner, was notably increased in OSCC compared with CP, BN and EOM. The expression was also enhanced in LOM compared with EOM. Expressed protein sequences from western blots were verified by LC-MS/MS. Western blots were then performed with individual samples in each group. The results showed the elevated expression of TLR4 in LOM and OSCC, compared with that in CP and BN, the increased expression of NF-κB in LOM and OSCC, compared with CP and in LOM compared with BN, and the enhanced expression of SENP7 in LOM and OSCC, compared with that in CP and BN. In conclusion, discrete clusters of EOM, LOM, OSCC, BN and CP groups and potential protein candidates associated with the diseases were demonstrated by salivary proteomics. Western blot analysis verified SENP7, TLR4 and NF-κB as potential salivary biomarkers of canine oral tumors.

Adjuvant anthracycline-based vs metronomic chemotherapy vs no medical treatment for dogs with metastatic splenic hemangiosarcoma: A multi-institutional retrospective study of the Italian Society of Veterinary Oncology

Treatment options for dogs with metastatic (stage III) splenic hemangiosarcoma are limited. A doxorubicin-based chemotherapy regimen is commonly administered; however, there are no published data to support this practice. The aim of this study was to investigate the impact of maximum-tolerated-dose chemotherapy (MTD), metronomic chemotherapy (MC) and no adjuvant treatment on outcome in dogs with stage III splenic hemangiosarcoma undergoing splenectomy. Medical records of dogs with stage III splenic hemangiosarcoma that underwent splenectomy followed by MTD chemotherapy, MC or no adjuvant treatment were retrieved. Time to progression (TTP), survival time (ST) and toxicity were evaluated. One hundred three dogs were identified: 23 received adjuvant MTD, 38 MC and 42 were not medically treated. Overall median TTP and ST were 50 (95% confidence interval [CI], 39-61) and 55 days (95% CI, 43-66), respectively. Dogs treated with adjuvant MTD had a significantly longer TTP and ST compared with dogs receiving MC (median TTP, 134 vs 52 days, P = .025; median ST, 140 vs 58 days, P = .023, respectively). Dogs treated by splenectomy only had the shortest median TTP (28 days) and ST (40 days). However, treatment-related adverse events (AEs) were significantly more frequent in the MTD group (P = .017). The outcome for dogs with metastatic splenic hemangiosarcoma is poor. While MTD showed greater efficacy compared to MC, toxicity was higher in this group. Treatment-related AEs need to be carefully balanced against this modest survival prolongation when offering adjuvant MTD to dogs with advanced stage hemangiosarcoma.

Colonic malignant peripheral nerve sheath tumour in a cat

Case summary

A 14-year-old male neutered domestic mediumhair cat presented with a 4 month history of inappetence and weight loss. Pertinent abnormalities on haematology and biochemistry included a mild microcytic regenerative anaemia (packed cell volume [PCV] 24% [reference interval (RI) 30–45%], mean cell volume 30.8 fl [RI 40–45 fl], absolute reticulocyte count 326.8 × 10¹²) and increased alkaline phosphatase activity (76 IU/l; RI <50 IU/l). Abdominal ultrasound and CT scan revealed masses in the transverse colon (2.0 cm × 1.2 cm) and right medial liver lobe (5.0 cm diameter). Thoracic radiographs were unremarkable. Right medial liver lobe resection and colectomy were performed. Immunohistochemistry was positive for S-100 protein, vimentin and glial fibrillary acidic protein, very weakly positive for c-kit and negative for muscle-specific actin and CD18, consistent with a colonic malignant peripheral nerve sheath tumour (MPNST) with a hepatic metastasis. Postoperative treatment with metronomic cyclophosphamide was well tolerated. Eighteen months postoperatively the cat re-presented after 3 days of progressive lethargy and inappetence. Haematology revealed a marked non- or pre-regenerative anaemia (PCV 10%). Coagulation times were prolonged (prothrombin time 39 s [RI 15–22 s] and activated partial thromboplastin time >300 s [RI 65–119 s]). Abdominal ultrasound identified multiple renal and hepatic nodules. Euthanasia was performed and post-mortem examination confirmed metastasis of the MPNST.

Relevance and novel information

This report describes the treatment of a metastatic colonic peripheral nerve sheath tumour in a cat. Feline visceral MPNSTs are rare and little is known about prognosis or optimal treatment.

Canine myxosarcomas, a retrospective analysis of 32 dogs (2003-2018)

Background

Myxosarcomas are known to be classified as soft tissue sarcomas. However, there is limited clinical characterization pertaining specifically to canine cutaneous myxosarcomas in the literature. The objective of this study is to evaluate the local recurrence rate, metastatic rate and prognosis of canine myxosarcoma.

Results

A total of 32 dogs diagnosed with myxosarcoma via histopathology were included in this retrospective study. All dogs had surgical resection. No adjunct treatments were performed in 9 dogs, while 22 dogs also received either radiation therapy or chemotherapy, or a combination of both. One dog received only NSAID after surgery. Overall median survival time (MST) was 730 days (range 20–2345 days). The MST of dogs with a tumor mitotic count < 10/10 HPF was 1393 days (range 20–2345 days). The dogs with a tumor mitotic count of 10 or greater/10 HPF had a MST of 433 days (range 169–831 days). There was no significant difference of MST among different treatment modalities. Local recurrence was noted in 13 cases (40.6%) and the median time to recurrence was 115.5 days (range 50–1610 days). The median time to local recurrence in dogs with mitotic count of < 10/10 HPF was 339 days (range 68–1610 days) and in dogs with mitotic count of 10 or greater/10 HPF was 119 days (range 50–378). Metastasis to local lymph node or lung was noted in 8 cases (25%) with median time to metastasis of 158.5 days (range 0–643 days).

Conclusions

Based on the results of this retrospective study, myxosarcoma may have a higher local recurrence rate and risk of metastasis to the local lymph nodes compared to other soft tissue sarcomas.

Soft tissue sarcoma in dogs: A treatment review and a novel approach using electrochemotherapy in a case series

Canine soft tissue sarcomas (STSs) are locally invasive mesenchymal neoplasms. Electrochemotherapy (ECT) is an antitumour local ablative treatment that uses electric pulses to enhance the intracellular delivery of cytotoxic drugs. The aim of this retrospective study was to review the current treatment for STSs and to evaluate the efficacy and safety of ECT with bleomycin in canine STSs. Fifty-two dogs with 54 STSs were included. Three groups were arranged: (a) ECT alone, (b) intra-operative ECT and (c) adjuvant ECT. Signalment, tumour size, location, histological grade and margins and ECT parameters were collected. Recurrence rate (RR) and disease-free interval (DFI) were calculated. Treatment toxicity was assessed using a 6-point scale. STSs were mostly located on limbs (77.8%). Median tumour size was 4.3 cm (range 0.4-17.0 cm). Most STSs were grade I (47.7%) and II (50.0%), and histological margins were incomplete in 94.5% of cases. Two complete remissions, one partial remission and one stable disease were recorded in group 1. Group 2 and 3 were similar for tumour location, size and grade, histological margins, treatment toxicity, pulse frequency and voltage. Moreover, RR and DFI were similar between group 2 and 3 (23% and 25%, 81.5 and 243 days, respectively). Local toxicity post ECT was mild (score ≤ 2) in 66.7% of cases. Higher toxicity score was associated with higher pulse voltage (1200 vs 1000 V/cm) (P = 0.0473). ECT coupled with bleomycin resulted safe and efficient in tumour local control and should be considered as an option for treatment of canine STSs.

Evaluation of metronomic cyclophosphamide chemotherapy as maintenance treatment for dogs with appendicular osteosarcoma following limb amputation and carboplatin chemotherapy

OBJECTIVE To determine the effectiveness of metronomic cyclophosphamide (MC) chemotherapy (primary treatment of interest) with adjuvant meloxicam administration as maintenance treatment for dogs with appendicular osteosarcoma following limb amputation and carboplatin chemotherapy. DESIGN Retrospective case series with nested cohort study. ANIMALS 39 dogs with a histologic diagnosis of appendicular osteosarcoma that underwent limb amputation and completed carboplatin chemotherapy from January 2011 through December 2015. PROCEDURES Dogs were grouped by whether carboplatin chemotherapy had been followed with or without MC chemotherapy (15 mg/m², PO, q 24 h) and meloxicam (0.1 mg/kg [0.045 mg/lb], PO, q 24 h). The Breslow rank test was used to assess whether MC chemotherapy was associated with overall survival time (OST) and disease progression-free time (PFT) after limb amputation. RESULTS 19 dogs received carboplatin and MC chemotherapy, and 20 dogs received only carboplatin chemotherapy. No differences were identified between these groups regarding age, reproductive status, body weight, serum alkaline phosphatase activity, tumor location, or histologic grade or subtype of osteosarcoma. Median duration of MC chemotherapy for dogs in the carboplatin-MC group was 94 days (range, 7 to 586 days); this treatment was discontinued for 11 (58%) dogs when cystitis developed. Overall, 11 (28%) dogs survived to the time of analysis, for a median follow-up period of 450 days (range, 204 to 1,400 days). No difference in median PFT or OST was identified between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE Maintenance MC chemotherapy following limb amputation and completed carboplatin chemotherapy was associated with no increase in PFT or OST in dogs with appendicular osteosarcoma. Cystitis was common in MC-treated dogs, and prophylactic treatment such as furosemide administration could be considered to reduce the incidence of cystitis in such dogs.

Adjuvant Thalidomide and Metronomic Chemotherapy for the Treatment of Canine Malignant Mammary Gland Neoplasms

BACKGROUND/AIM

The aim of the present study was to evaluate a multimodal approach for the treatment of canine malignant mammary gland neoplasms, including surgery, chemotherapy, thalidomide, and metronomic chemotherapy (MC).

MATERIALS AND METHODS

Fifty-eight female dogs were submitted to four different treatments: surgery; surgery with chemotherapy; surgery with chemotherapy and thalidomide; and surgery with chemotherapy and metronomic chemotherapy and overall survival was evaluated.

RESULTS

No statistical difference was found in the proliferative index and microvessel density of primary neoplasms and distant metastases following thalidomide treatment. Diffuse intense inflammatory infiltrate was predominant in primary tumors and diffuse moderate inflammatory infiltrate in metastatic lesions. No statistically significant difference was observed in median survival time (MST) between treatment groups when including all clinical stages (p=0.3177). However, animals diagnosed with distant metastasis treated with surgery and chemotherapy associated with thalidomide or MC presented longer MST when compared to animals treated only with surgery or surgery and chemotherapy (p<0.0001).

CONCLUSION

The proposed multimodal therapy protocols including antiangiogenic and immunomodulatory therapies demonstrated a clinical benefit for patients in advanced clinical stages.

Retrospective evaluation of toceranib phosphate (Palladia®) use in the treatment of gastrointestinal stromal tumors of dogs

Background

Gastrointestinal stromal tumors (GISTs) are uncommon intestinal neoplasms in the dog. Literature regarding adjunctive therapy for GISTs in dogs is sparse. High‐risk GISTs in humans respond to tyrosine kinase inhibition in the adjuvant setting.

Objectives

To review cases of toceranib phosphate use in dogs with GISTs and provide initial assessment of possible biological activity. A secondary aim was to evaluate patient and tumor characteristics for possible prognostic value.

Animals

Twenty‐seven dogs with confirmed GISTs based on histopathology and immunohistochemistry treated with toceranib.

Methods

Retrospective study in which cases of toceranib use in dogs with GIST were solicited using the American College of Veterinary Internal Medicine Oncology and Small Animal Internal Medicine listservs.

Results

Five of 7 dogs with gross disease experienced clinical benefit (71%; 3 complete responses, 1 partial response, 1 stable disease). These included 2 dogs with durable responses after toceranib discontinuation. Median progression‐free interval (PFI) in dogs with gross disease was 110 weeks (range, 36‐155 weeks). Median PFI in dogs with microscopic disease was 67 weeks (range, 9‐257 weeks). Metastasis at diagnosis (P = 0.04) and high mitotic index (P < 0.001) were associated with shorter PFI in toceranib‐treated dogs.

Conclusions and Clinical Importance

Biological activity of toceranib is evident in dogs with gross disease. Metastasis of GIST at diagnosis, as well as high tumor mitotic index, was associated with shorter PFI in toceranib‐treated dogs. Larger studies are needed to define postsurgical risk and refine the use of toceranib in dogs with gross and microscopic GIST.

Canine sarcomas as a surrogate for the human disease

Pet dogs are becoming increasingly recognized as a population with the potential to inform medical research through their treatment for a variety of maladies by veterinary health professionals. This is the basis of the One Health initiative, supporting the idea of collaboration between human and animal health researchers and clinicians to study spontaneous disease processes and treatment in animals to inform human health. Cancer is a major health burden in pet dogs, accounting for approximately 30% of deaths across breeds. As such, pet dogs with cancer are becoming increasingly recognized as a resource for studying the pharmacology and therapeutic potential of anticancer drugs and therapies under development. This was recently highlighted by a National Academy of Medicine Workshop on Comparative Oncology that took place in mid-2015 (http://www.nap.edu/21830). One component of cancer burden in dogs is their significantly higher incidence of sarcomas as compared to humans. This increased incidence led to canine osteosarcoma being an important component in the development of surgical approaches for osteosarcoma in children. Included in this review of sarcomas in dogs is a description of the incidence, pathology, molecular characteristics and previous translational therapeutic studies associated with these tumors. An understanding of the patho-physiological and molecular characteristics of these naturally occurring canine sarcomas holds great promise for effective incorporation into drug development schemas, for evaluation of target modulation or other pharmacodynamic measures associated with therapeutic response. These data could serve to supplement other preclinical data and bolster clinical investigations in tumor types for which there is a paucity of human patients for clinical trials.

Proteomic analysis of canine oral tumor tissues using MALDI-TOF mass spectrometry and in-gel digestion coupled with mass spectrometry (GeLC MS/MS) approaches

Oral tumors, including highly invasive and metastatic oral melanoma (OM), non-tonsillar oral squamous cell carcinoma (OSCC) and benign tumors (BN), are common neoplasms in dogs. Although these tumors behave differently, limited data of their protein expression profiles have been exhibited, particularly at the proteome level. The present study aimed to i.) characterize peptide-mass fingerprints (PMFs) and identify potential protein candidates of OM, OSCC, BN and normal control subjects, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS), ii.) identify potential protein candidates associated with the diseases, using in-gel digestion coupled with mass spectrometric analysis (GeLC-MS/MS) and iii.) search for relationships between chemotherapy drugs and disease-perturbed proteins. A distinct cluster of each sample group and unique PMFs with identified protein candidates were revealed. The unique peptide fragment at 2,274 Da of sacsin molecular chaperone (SACS) was observed in early-stage OM whereas the fragment at 1,958 Da of sodium voltage-gated channel alpha subunit 10 (SCN10A) was presented in early- and late-stage OM. The peptide mass at 2,316 Da of Notch1 appeared in early-stage OM and benign oral tumors while the peptide mass at 2,505 Da of glutamate ionotropic receptor N-methyl-D-aspartate type subunit 3A (GRIN3A) was identified in all groups. Markedly expressed proteins from GeLC-MS/MS included Jumonji domain containing 1C (JMJD1C) in benign tumors, inversin (INVS) and rho guanine nucleotide exchange factor 28 (ARHGEF28) in OM, BTB domain-containing 16 (BTBD16) in OSCC, and protein tyrosine phosphatase non-receptor type 1 (PTPN1), BRCA2, DNA repair associated (BRCA2), WW domain binding protein 2 (WBP2), purinergic receptor P2Y1 and proteasome activator subunit 4 (PSME4) in all cancerous groups. The network connections between these proteins and chemotherapy drugs, cisplatin and doxorubicin, were also demonstrated. In conclusion, this study unveiled the unique PMFs and novel candidate protein markers of canine oral tumors.

Glutathione-S-transferase-theta genotypes and the risk of cyclophosphamide toxicity in dogs

The antineoplastic agent cyclophosphamide (CP) has dose-limiting side effects including sterile haemorrhagic cystitis (SHC), bone marrow (BM) suppression and gastrointestinal (GI) toxicity in dogs. The metabolites acrolein and phosphoramide that mediate these toxicities are glutathione-S-transferase (GST) substrates, and low functioning GST alleles are associated with CP toxicity in humans. The aim of this study was to determine whether variants in 2 canine GST genes, GSTT1 and GSTT5, were over-represented in dogs that developed CP toxicity. Dogs undergoing pulse or metronomic CP chemotherapy were recruited (n = 101) and genotyped for 6 GSTT1 polymorphisms and 1 GSTT5 6-bp deletion that leads to non-functional enzyme. Median cumulative CP dosages for dogs with SHC (1350 mg/m² ) were significantly higher than for dogs with GI/BM toxicity (871 mg/m² ) or no toxicity (991 mg/m² ; P = .0012). Dogs with SHC were more likely to have had metronomic (84.2%, 16 of 19 SHC cases) vs pulse (15.8%, 3 of 19 SHC cases) CP dosing (P < .0001). All dogs with BM or GI toxicity (n = 30) had pulse chemotherapy. GSTT1 and GSTT5 variant allele frequencies were not significantly different in CP-treated dogs with SHC or GI/BM toxicity compared to dogs without documented adverse effects. Work is underway to identify which canine GSTs detoxify acrolein and phosphoramide, so that better tools are available to predict the risk of CP toxicity in dogs.

Use of metronomic chemotherapy in the management of a cat with abdominal haemangiosarcoma

CASE SUMMARY

A 12-year-old entire domestic shorthair was evaluated for a 5 week history of intermittent vomiting, loss of appetite and weight loss. Abdominal ultrasound revealed a multi-lobulated heterogeneous mass adjacent to the mesenteric vessels. Cytology from fine-needle aspirates was non-diagnostic. Histopathology from a Tru-cut biopsy was consistent with haemangiosarcoma. The cat was treated with metronomic chemotherapy using oral cyclophosphamide. The cat remained clinically well and was euthanased 10 months after diagnosis owing to development of a haemoabdomen.

RELEVANCE AND NOVEL INFORMATION

Prognosis of feline abdominal haemangiosarcoma is generally poor and limited information on treatment is available in the veterinary literature. The use of metronomic chemotherapy with oral cyclophosphamide in this cat provided a 10 month period of good-quality life.

Hemangiosarcoma in a Dog: Unusual Presentation and Increased Survival Using a Complementary/Holistic Approach Combined with Metronomic Chemotherapy

This case report documents the clinical and pathologic findings in a 12-year-old terrier mix with intraocular and splenic hemangiosarcoma. Pathologic findings in both the spleen and globe were consistent with hemangiosarcoma with a low mitotic count. Initial treatment consisted of enucleation and then splenectomy followed by one cycle of conventional doxorubicin chemotherapy. Due to poor tolerance, a subsequent treatment regimen consisted of metronomic chemotherapy with chlorambucil combined with an alternative/complementary regimen of I'm-Yunity (polysaccharopeptide) and Yunnan Baiyao. Follow-up thoracic radiographs and abdominal ultrasounds over a period of 24 months showed no evidence of pulmonary, hepatic, or right atrial metastases, during which time the patient had an excellent quality of life. However, shortly after achieving two-year survival, the patient developed new onset seizures unresponsive to anticonvulsant therapy. Therefore, a decision was made to euthanize the dog given that the most likely etiology of the seizures was a brain tumor. Overall, this is an exceptional treatment response given the poor survival statistics of hemangiosarcoma even with conventional chemotherapy. However, additional clinical pharmacology and clinical trial data are needed to further support the use of a complementary/holistic approach in combination with metronomic chemotherapy.

Update on Cancer Treatment in Exotics

Treatment options for animals with cancer are rapidly expanding, including in exotic animal medicine. Limited information is available about treatment effects in exotic pet species beyond individual case reports. Most cancer treatment protocols in exotic animals are extrapolated from those described in humans, dogs, and cats. This review provides an update on cancer treatment in exotic animal species. The Exotic Species Cancer Research Alliance accumulates clinical cases in a central location with standardized clinical information, with resources to help clinicians find and enter their cases for the collective good of exotic clinicians and their patients.

Evaluation of information presented within soft tissue sarcoma histopathology reports in the United States: 2012-2015

Despite the existence of the American College of Veterinary Pathology guidelines for tumour biopsy specimens, anecdotally the authors' have seen inconsistency of reporting of information on the pathology report for canine soft tissue sarcomas (STSs). If crucial aspects are not reported this can result in slower or impeded patient care. This retrospective study evaluated 255 STS histopathology reports submitted from across the United States. Reports were evaluated by a single observer to assess for information contained in 5 main categories: patient history and signalment, gross and microscopic description, grading, histologic margins and the comments section. Inclusion criteria for histopathology reports included a final diagnosis of STS, having a microscopic description and resulting from the initial surgical resection. The majority of the reports stated the patient signalment (91.2%) and clinical history (90.8%). However, only 64.8% of the reports had a gross description of the specimen. Histologic margin description was present in 229 reports (91.6%), however, only 149 reports (59.6%) stated an objective measurement of these margins. Histologic classification was stated in 50.0% of the reports, while grade was given on 97.2% of the reports. Variability in histopathologic reporting including histologic margin description for resected canine STS was identified. Given surgical treatment is the mainstay for STS and histopathological assessment plays an important role in determination of whether additional surgery, radiation or chemotherapy is needed. Standardization or checklists like the American College of Pathology utilize may be helpful to ensure histopathologic characteristics are reported that may guide further treatment recommendations.

Molecular iodine/doxorubicin neoadjuvant treatment impair invasive capacity and attenuate side effect in canine mammary cancer

Background

Mammary cancer has a high incidence in canines and is an excellent model of spontaneous carcinogenesis. Molecular iodine (I₂) exerts antineoplastic effects on different cancer cells activating re-differentiation pathways. In co-administration with anthracyclines, I₂ impairs chemoresistance installation and prevents the severity of side effects generated by these antineoplastic drugs. This study is a random and double-blind protocol that analyzes the impact of I₂ (10 mg/day) in two administration schemes of Doxorubicin (DOX; 30 mg/m2) in 27 canine patients with cancer of the mammary gland. The standard scheme (sDOX) includes four cycles of DOX administered intravenously for 20 min every 21 days, while the modified scheme (mDOX) consists of more frequent chemotherapy (four cycles every 15 days) with slow infusion (60 min). In both schemes, I₂ or placebo (colored water) was supplemented daily throughout the treatment.

Results

mDOX attenuated the severity of adverse events (VCOG-CTCAE) in comparison with the sDOX group. The overall tumor response rate (RECIST criteria) for all dogs was 18% (interval of reduction 48–125%), and no significant difference was found between groups. I₂ supplementation enhances the antineoplastic effect in mDOX, exhibiting a significant decrease in the tumor epithelial fraction, diminished expression of chemoresistance (MDR1 and Survivin) and invasion (uPA) markers and enhanced expression of the differentiation factor known as peroxisome proliferator-activated receptors type gamma (PPARγ). Significant tumor lymphocytic infiltration was also observed in both I₂-supplemented groups. The ten-month survival analysis showed that the entire I₂ supplementation (before and after surgery) induced 67–73% of disease-free survival, whereas supplementation in the last period (only after surgery) produced 50% in both schemes.

Conclusions

The mDOX+I₂ scheme improves the therapeutic outcome, diminishes the invasive capacity, attenuates the adverse events and increases disease-free survival. These data led us to propose mDOX+I₂ as an effective treatment for canine mammary cancer.

Survival analysis of dogs with advanced primary lung carcinoma treated by metronomic cyclophosphamide, piroxicam and thalidomide

Unresectable or metastatic (advanced) primary pulmonary carcinoma (PPC) represents a therapeutic challenge where surgery may be contraindicated and the therapeutic role of maximum-tolerated dose (MTD) chemotherapy remains uncertain. This study was undertaken to explore the impact of metronomic chemotherapy (MC) in dogs with advanced PPC. Previously untreated dogs with advanced (T3 or N1 or M1) PPC, with complete staging work-up and follow-up data, receiving MC (comprising low-dose cyclophosphamide, piroxicam and thalidomide), surgery, MTD chemotherapy or no oncologic treatment were eligible for inclusion. For all patients, time to progression (TTP) and survival time (ST) were evaluated. Quality-of-life (QoL) was only evaluated in patients receiving MC. To assess QoL, owners of dogs receiving MC were asked to complete a questionnaire before and during treatment. Ninety-one dogs were included: 25 received MC, 36 were treated with surgery, 11 with MTD chemotherapy and 19 received no treatment. QoL was improved in dogs receiving MC. Median TTP was significantly longer in patients receiving MC (172 days) than patients undergoing surgery (87 days), receiving MTD chemotherapy (22 days), or no oncologic treatment (20 days). Median ST was similarly longer in patients receiving MC (139 days) than those undergoing surgery (92 days), MTD chemotherapy (61 days) and no oncologic treatment (60 days). In dogs with advanced PPC, MC achieved a measurable clinical benefit without significant risk or toxicity. This makes MC a potential alternative to other recognized management approaches.

Canine Soft Tissue Sarcomas: Can Being a Dog's Best Friend Help a Child?

Soft tissue sarcomas (STSs) remain a therapeutic challenge for pediatric and adolescent and young adult (AYA) patients. Still today, surgery, radiation therapy, and chemotherapy remain the mainstay of treatment. Obstacles in developing new treatment approaches to improve the outcome are: few patients to enroll in clinical trials, and the diversity of tumor biology between histologic subtypes. Pet dogs may offer an additional strategy to discover and test new therapeutic avenues. The number of dogs diagnosed with a STS each year in the United States is estimated to be around 27,000 to 95,000. In comparison, approximately 900 children less than 20 years old and 1,500 AYAs between 15 and 29 years old are diagnosed with a STS each year in the United States. The mainstay for treatment of STSs in dogs is also surgery, with radiation therapy and chemotherapy when necessary. Similar to what is seen in humans, grade and stage are prognostic in dogs. In one comparative study of the histology and immunohistochemistry of canine STSs, most tumors were diagnosed as the human equivalent of undifferentiated sarcoma, spindle cell sarcoma, or unclassified spindle cell sarcoma. But much work remains to be done to fully assess the validity of canine STSs as a model. Gene expression analysis has been done in a limited number of canine STSs. Tissue banking, development of cell lines, and the ability to mobilize large-scale clinical trials will become essential in veterinary medicine to benefit both dogs and humans.

Adjuvant Doxorubicin with or without Metronomic Cyclophosphamide for Canine Splenic Hemangiosarcoma

This retrospective study investigated the outcome of 33 dogs with splenic hemangiosarcoma treated with surgery followed by adjuvant dose-intensified doxorubicin (DOX) with or without low-dose metronomic cyclophosphamide (LDM-C) maintenance therapy. Among the 33 dogs, 18 dogs received LDM-C. Clinical stage was available for all dogs (5 stage I, 18 stage II, and 10 stage III). Nine dogs had macroscopic, and 24 dogs had microscopic disease at the start of DOX treatment. Median progression-free survival (PFS) and overall survival were 125 and 133 days, respectively. Clinical stage and tumor burden (microscopic versus macroscopic) at the start of chemotherapy was prognostic for PFS. No significant difference was observed in PFS or overall survival for the addition of LDM-C after a completed DOX protocol (P = .563 and P = .148, respectively). Based on the results of this retrospective study, the addition of LDM-C therapy as a maintenance regimen following a completed protocol of DOX adjuvant treatment of canine hemangiosarcoma may not improve outcome.

The use of low-dose metronomic chemotherapy in dogs-insight into a modern cancer field

The era of chemotherapy, which started in the middle of the last century, has been ruled by the routine use of dose-intense protocols, based on the "maximum-tolerated dose" concept. By promoting a balance between patient's quality of life and the goal of rapidly killing as many tumour cells as possible, these protocols still play a prominent role in veterinary oncology. However, with the opening of a new millennium, metronomic chemotherapy (MC) started to be considered a possible alternative to traditional dose-intense chemotherapy. Characterized by a long-term daily administration of lower doses of cytotoxic drugs, this new modality stands out for its unique combination of effects, namely on neovascularization, immune response and tumour dormancy. This article reviews the rationale for treatment with MC, its mechanism of action and the main studies conducted in veterinary medicine, and discusses the key challenges yet to be solved.

Potency and stability of compounded formulations of chlorambucil, melphalan and cyclophosphamide

BACKGROUND

Oral chemotherapy agents are frequently compounded in veterinary medicine however, the potency of some formulations have been shown to vary from that of Food and Drug Administration (FDA)-approved products.

AIMS

The objective of this study was to evaluate the potency and stability of three compounded oral chemotherapeutics commonly prescribed to be administered over time.

MATERIALS & METHODS

Compounded chlorambucil 1 mg, cyclophosphamide 5 mg and melphalan 1 mg were obtained and for potency tested upon receipt and 6 weeks later.

RESULTS

Potency ranged from 71 to 104% for chlorambucil and 58 to 109% for melphalan; 1/4 and 2/4 samples were <90% of labelled strength at baseline and 6 weeks, respectively, for both drugs. Potency of cyclophosphamide ranged from 92 to 107% with all samples +/-10% of labelled strength at all time points.

DISCUSSION/CONCLUSION

These results demonstrate variability of compounded chemotherapy products, and highlight the need to consider both potency and stability when prescribing orally compounded chemotherapy.

Avian Oncology: Diseases, Diagnostics, and Therapeutics

Companion birds are increasingly living longer due to improved husbandry, nutrition, and veterinary care. As a consequence, a growing number of geriatric disease conditions are diagnosed and managed by veterinarians. Awareness of bird owners of diagnostic and treatment options for neoplastic diseases in humans and domestic animals has led to increasing demand to provide advanced diagnostic and treatment modalities for companion birds diagnosed with neoplasia. Treatment remains challenging in many companion birds due to the lack of information regarding prognosis and efficacy of antineoplastic treatments in these species. There is no established standard of care for most tumors in companion birds.