Minimally invasive splenectomy is associated with a low perioperative complication rate and short operative time in cats.

OBJECTIVE: To report the perioperative outcome and complications in cats undergoing minimally invasive splenectomy. ANIMALS: 17 client-owned cats. METHODS: Perioperative data were collected from cats undergoing minimally invasive splenectomy from September 2010 to June 2023. Data included history, signalment, preoperative examination and diagnostic testing results, operative technique and time, perioperative outcomes, complications, hospitalization duration, histopathological diagnosis, and outcome. RESULTS: 13 spayed females and 4 neutered males were included, with a median age of 144 months (48 to 196 months). Seven cats underwent total laparoscopic splenectomy (TLS), with 1 cat requiring conversion from TLS to laparoscopic-assisted splenectomy (LAS) due to splenomegaly and an additional cat requiring conversion from TLS to open splenectomy due to uncontrollable splenic capsular hemorrhage. Ten cats underwent LAS, with 1 cat requiring conversion to open splenectomy due to splenomegaly. Additional procedures were performed in 13 cats, with the most common being liver biopsy in 10 cats. Median operative times were 50 minutes (45 to 90 minutes) for TLS and 35 minutes (25 to 80 minutes) for LAS. An intraoperative complication occurred in 1 cat. All but 1 cat survived to discharge. Median follow-up time was 234 days (18 to 1,761 days), with 15 of 16 cats confirmed alive at 30 days and 9 of 16 cats alive at 180 days postoperatively. CLINICAL RELEVANCE: Minimally invasive splenectomy in this cohort of cats was associated with short operative times and a low perioperative complication rate. Veterinary surgeons may consider minimally invasive splenectomy as an efficient and feasible technique in the treatment of splenomegaly or modestly sized splenic masses for diagnostic and therapeutic purposes in cats.

Thoracoscopic resection of lung masses is associated with excellent survival to discharge and good long-term outcomes.

OBJECTIVE: To report and evaluate risk factors for conversion and perioperative and long-term outcomes in dogs undergoing thoracoscopic lung lobectomy for resection of lung masses. ANIMALS: 61 client-owned dogs. METHODS: This retrospective cohort study (June 11, 2008, to February 14, 2020) of data collected from medical records included signalment, results of diagnostic imaging, surgical technique, surgical and anesthesia time, mass location and size, hospitalization time, histopathologic findings, and long-term outcome. Follow-up was obtained from medical records and telephone contact with owners or referring veterinarians. RESULTS: Histopathology results were available for 60 of 61 tumors. Fifty-seven (95%) were considered primary lung tumors, of which 46 (81%) were carcinomas. Clean surgical margins were achieved in 46 of 52 (88%) dogs. Conversion from thoracoscopy to thoracoscopic-assisted or open surgery occurred in 16 of 61 (26%) dogs. Larger tumor diameter (≥ 5 cm) and lymphadenopathy detected by preoperative CT scan were significantly associated with increased risk of conversion. There was no association between conversion and patient weight, body condition score, and tumor location. All 61 dogs survived to discharge, and 56 of 57 were alive 1 month postoperatively. Median overall survival time was 311 days (95% CI, 224 to 570 days). Tracheobronchial lymphadenopathy on preoperative CT scans was associated with shorter postoperative survival (P < .001). Patient age, tumor diameter, adjuvant chemotherapy following surgery, and incomplete margins were not associated with survival time. CLINICAL RELEVANCE: Dogs had high survival to discharge and good long-term prognosis following thoracoscopic lung lobectomy. However, larger tumor size and tracheobronchial lymphadenopathy may increase the likelihood of conversion.

Treatment of retroperitoneal sarcoma results in improved outcomes.

OBJECTIVE: To report the clinical characteristics, treatments, and outcomes in a cohort of dogs with histologically confirmed retroperitoneal sarcoma (RPS) and to identify potential variables of prognostic significance. ANIMALS: 46 client-owned dogs from 10 clinics with histopathologic diagnosis of a sarcoma originating from the retroperitoneal space. METHODS: Medical records were retrospectively reviewed to obtain information regarding clinical characteristics, treatments, and outcomes. Recorded variables were analyzed to report descriptive data for all cases and overall survival time. Multivariate analysis was utilized to evaluate prognostic factors for overall survival. RESULTS: Hemangiosarcoma was the most common histologic subtype diagnosed (76.1%). Cytoreductive and curative intent surgical excision of the RPS was attempted in 12 and 22 dogs, respectively; 12 dogs underwent no surgery or had an exploratory laparotomy with incisional biopsy only. Nineteen dogs received adjuvant chemotherapy, either injectable or metronomic, and 1 dog received adjuvant radiation therapy. Fourteen of the 34 (41.2%) surgically treated dogs developed evidence of local recurrence, but there was no difference in local recurrence when comparing dogs categorized as curative intent versus cytoreductive surgery. The median overall survival time was 238 days. On multivariable analysis, treatment approach was associated with survival with surgical excision (vs palliative treatment) and adjuvant chemotherapy following surgery being protective against death. A diagnosis of hemangiosarcoma was associated with a greater hazard of death. CLINICAL RELEVANCE: This study demonstrates a substantially greater survival time than previously published and suggests a survival benefit from surgical excision and adjuvant chemotherapy.

Veterinary Interventional Oncology.

Interventional oncology (IO) is a rapidly growing field in veterinary medicine and has been accepted as a fourth pillar of treatment of neoplastic disease with other modalities including surgery, chemotherapy, and radiation therapy. The major categories of IO therapies in companion animals are focused on the use of locoregional therapies and stenting of malignant obstructions. Although significant assessment of veterinary IO techniques is still necessary, early evaluation of these varying techniques is demonstrating promising results.

Adrenal tumors treated by adrenalectomy following spontaneous rupture carry an overall favorable prognosis: retrospective evaluation of outcomes in 59 dogs and 3 cats (2000-2021).

OBJECTIVE: To conduct a retrospective multi-institutional study reporting short- and long-term outcomes of adrenalectomy in patients presenting with acute hemorrhage secondary to spontaneous adrenal rupture. ANIMALS: 59 dogs and 3 cats. METHODS: Medical records of dogs and cats undergoing adrenalectomy between 2000 and 2021 for ruptured adrenal masses were reviewed. Data collected included clinical presentation, preoperative diagnostics, surgical report, anesthesia and hospitalization findings, histopathology, adjuvant treatments, and long-term outcome (recurrence, metastasis, and survival). RESULTS: Median time from hospital admission to surgery was 3 days, with 34% of surgeries being performed emergently (within 1 day of presentation). Need for intraoperative blood transfusion was significantly associated with emergent surgery and presence of active intraoperative hemorrhage. The short-term (≤ 14 days) complication and mortality rates were 42% and 21%, respectively. Negative prognostic factors for short-term survival included emergent surgery, intraoperative hypotension, and performing additional surgical procedures. Diagnoses included adrenocortical neoplasia (malignant [41%], benign [12%], and undetermined [5%]), pheochromocytoma (38%), a single case of adrenal fibrosis and hemorrhage (2%), and a single case of hemangiosarcoma (2%). Local recurrence and metastasis of adrenocortical carcinoma were confirmed in 1 and 3 cases, respectively. Overall median survival time was 574 days and 900 days when short-term mortality was censored. No significant relationship was found between histopathological diagnosis and survival. CLINICAL RELEVANCE: Adrenalectomy for ruptured adrenal gland masses was associated with similar short- and long-term outcomes as compared with previously reported nonruptured cases. If hemodynamic stability can be achieved, delaying surgery and limiting additional procedures appear indicated to optimize short-term survival.

A Systematic Review of Canine Cystectomy: Indications, Techniques, and Outcomes.

This review provides a summary of the literature encompassing partial and total cystectomy procedures in dogs and subsequent conclusions that can be drawn. Surgical excision as a component of treatment for lower urinary tract neoplasia in dogs may enhance survival time and result in acceptable quality of life, though risk for surgical complications is substantial, particularly following total cystectomy procedures. However, for dogs with urothelial carcinoma, cystectomy is generally not considered curative and disease progression is common. Appropriate case selection and thorough preoperative discussion with owners regarding potential risks and benefits of cystectomy are imperative for successful outcomes.

Laparoscopic adrenalectomy for resection of unilateral noninvasive adrenal masses in dogs is associated with excellent outcomes in experienced centers.

OBJECTIVE: To report the short- and long-term outcomes of laparoscopic adrenalectomy (LA) for resection of unilateral adrenal masses and to document risk factors for conversion and peri- and postoperative morbidity. ANIMALS: 255 client-owned dogs. METHODS: Dogs were included if LA was attempted for resection of a unilateral adrenal mass. Medical records were evaluated and relevant data were reported, including complications, conversion, perioperative death, and long-term outcomes. Signalment, clinicopathological data, and surgical experience were factors statistically evaluated for possible associations with capsular penetration during surgery, conversion, surgical time, duration of hospital stay, death prior to discharge, mass recurrence, and survival time. RESULTS: 155 dogs had left-sided tumors, and 100 had right-sided tumors. Conversion to an open approach was performed in 9.4% of cases. Capsular penetration (19.2%) and major hemorrhage (5.4%) were the most prevalent intraoperative complications. Of the dogs operated on, 94.9% were discharged from the hospital. Lesion side, portion of the gland affected, and surgeon experience influenced surgical time. Conversion rate increased with increasing body condition score and lesion size. Risk of death prior to discharge increased with increasing lesion size. Risk of conversion and death prior to discharge were lower when performed by more experienced surgeons. Capsular penetration during LA increased the risk of tumor recurrence. CLINICAL RELEVANCE: LA for resection of unilateral adrenal masses is associated with excellent outcomes in experienced centers. Surgeons with greater experience with LA have lower surgical times, conversion rates, and risk of death prior to discharge.

A 20-year scoping review of the veterinary interventional radiology and interventional endoscopy literature (2000-2019).

BACKGROUND: Interventional radiology (IR) and interventional endoscopy (IE) have broad potential for minimally invasive therapy in veterinary patients, but the scope of original peer-reviewed veterinary IR/IE research publications has not been described. OBJECTIVES: Catalogue published applications and indications for noncardiac therapeutic IR/IE in animals and describe type and quality of veterinary IR/IE research over 20 years. METHODS: Highly-cited veterinary journals were searched to identify articles published 2000 to 2019 involving therapeutic IR/IE applications for clinical veterinary patients. Articles were assigned a level of evidence (LOE) according to published standards. Authorship, animal data, study design, and interventions were described. Change in publication rate, study size, and LOE of IR/IE articles over time was analyzed. RESULTS: One hundred fifty-nine of 15 512 (1%) articles were eligible, including 2972 animals. All studies were low LOE and 43% were case reports with ≤5 animals. Number of IR/IE articles per year (P < .001), proportion of journals' articles pertaining to IR/IE (P = .02), and study size (P = .04) all increased over time, but LOE (P = .07) did not. Common target body systems were urinary (40%), digestive (23%) respiratory (20%), and vascular (13%). Common indications were nonvascular luminal obstructions (47%), object retrieval (14%), and congenital anomalies (13%). Most procedures involved indwelling medical devices or embolic agents, whereas tissue resection and other procedures were less common. Procedures utilized fluoroscopy (43%), endoscopy (33%), ultrasound (8%), digital radiography (1%), or fluoroscopy in combination with other modalities (16%). CONCLUSIONS: Treatments involving IR/IE have wide applicability in veterinary medicine but large, rigorous, and comparative studies describing these procedures are lacking.

Modified hemipelvectomy techniques in dogs and cats appear well tolerated with good functional outcomes.

OBJECTIVE: To describe the clinical characteristics, procedural techniques, complications, and outcomes of dogs and cats undergoing any of the following modified hemipelvectomy techniques: concurrent partial sacrectomy and/or partial vertebrectomy, osseous excision crossing midline, and reconstruction without the use of local musculature. ANIMALS: 23 client-owned animals (20 dogs and 3 cats) that underwent modified hemipelvectomy techniques. Animals that underwent traditional (nonmodified) hemipelvectomy techniques were excluded. PROCEDURES: The medical records of 3 academic institutions were reviewed, and data were recorded and analyzed. RESULTS: Modified hemipelvectomy was performed with partial sacrectomy and/or vertebrectomy in 11 dogs, excision crossing pelvic midline with concurrent limb amputation in 5 dogs and 2 cats, and closure without use of native muscle or mesh in 4 dogs and 1 cat. Surgery was performed for tumor excision in all cases. Excision was reported as complete in 16 of 23, incomplete in 6 of 23, and not recorded in 1 of 23 animals. All animals survived to discharge. Only animals undergoing partial sacrectomy/vertebrectomy (4/11) experienced postoperative mobility concerns. Major intra- or post-operative complications (grades 3 and 4) occurred in 2 dogs that underwent partial sacrectomy/vertebrectomy, and 1 of these animals experienced a complication that resulted in death. The median time to death or last follow-up was 251 days (range, 3 to 1,642). CLINICAL RELEVANCE: The modified hemipelvectomy techniques reported in this cohort were overall well tolerated with good functional outcomes. These findings support the use of these modified hemipelvectomy techniques in dogs and cats, and previous notions regarding tolerable hemipelvectomy procedures should be reconsidered. However, additional studies with larger numbers of patients undergoing modified hemipelvectomy techniques are needed to gain more information.

Short- and long-term outcomes associated with anal sacculectomy in dogs with massive apocrine gland anal sac adenocarcinoma.

OBJECTIVE: To evaluate short- and long-term outcomes for dogs undergoing anal sacculectomy for massive (> 5 cm) apocrine gland anal sac adenocarcinoma (AGASACA). ANIMALS: 28 client-owned dogs with massive AGASACA. PROCEDURES: A retrospective multi-institutional study was performed. Pre-, intra-, and post-operative data was collected, and variables were statistically analyzed for associations with progression-free interval (PFI) and overall survival (OS). RESULTS: At the time of anal sacculectomy, 19 (68%) dogs underwent concurrent iliosacral lymph node extirpation, including 17 of 18 (94%) dogs with suspected nodal metastasis preoperatively. Five (18%) dogs experienced grade 2 intraoperative complications. Ten (36%) dogs experienced postoperative complications, including 1 grade 3 and 1 grade 4 complication. No dogs had permanent fecal incontinence, tenesmus, or anal stenosis. Nineteen dogs received adjuvant chemotherapy, radiation, or both. Local recurrence occurred in 37% of dogs. Dogs with lymph node metastasis at surgery were more likely than dogs without metastasis to develop new/progressive lymph node metastasis (10/17 [59%] vs 0/10 [0%]; P = .003) and distant metastasis (7/17 [41%] vs 0/10 [0%]; P = .026). Median PFI was 204 days (95% CI, 145 to 392). Median OS was 671 days (95% CI, 225 to upper limit not reached). Nodal metastasis at the time of surgery was associated with shorter PFI (P = .017) but not OS (P = .26). Adjuvant therapy was not associated with outcome. CLINICAL RELEVANCE: Dogs with massive AGASACA experienced prolonged survival following anal sacculectomy despite a high incidence of local recurrence and metastasis. Lymph node metastasis at the time of surgery was a negative prognostic indicator for PFI but not OS.

Effect of conventional multilevel brachycephalic obstructive airway syndrome surgery on clinical and videofluoroscopic evidence of hiatal herniation and gastroesophageal reflux in dogs.

OBJECTIVE: To evaluate the effect of conventional multilevel surgery (CMS) for brachycephalic obstructive airway syndrome (BOAS) on associated sliding hiatal hernia (SHH) and/or gastroesophageal reflux (GER). STUDY DESIGN: Prospective clinical trial. ANIMALS: Sixteen client-owned dogs with clinical signs consistent with BOAS and associated SHH and GER. METHODS: All dogs were treated with 1 or more components of CMS including soft palate resection, laryngeal ventriculectomy, and alaplasty. A standardized Dog Swallowing Assessment Tool (Dog SAT) questionnaire was completed by owners preoperatively and postoperatively. Videofluoroscopic swallow studies (VFSS) were used to evaluate esophageal motility, gastroesophageal reflux, and hiatal herniation preoperatively, and in a subset of dogs postoperatively. Upper gastrointestinal endoscopic studies were performed to document esophagitis and lower esophageal sphincter pathology. RESULTS: All dogs were discharged from the hospital. One dog experienced aspiration pneumonia immediately postoperatively. Owner-assigned clinical scores improved in scores related to regurgitation after eating and regurgitation (P = .012) during increased activity/exercise (P = .002) between preoperative and postoperative time points. However, no improvement was detected in masked assessment of preoperative and postoperative VFSS studies in terms of GER frequency (P = .46) or severity (P = .79), SHH frequency (P = .082) or severity (P = .34) scores. CONCLUSION: Owners of dogs treated with CMS perceived an improvement in clinical signs of SHH and GER that was not confirmed by VFSS studies. CLINICAL SIGNIFICANCE: Conventional multilevel surgery in dogs with BOAS does not appear to consistently resolve SHH and GER, although clinical signs may improve.

MRI characteristics of canine prostatic neoplasia.

Magnetic resonance imaging (MRI) has been used to evaluate dogs with suspected prostatic neoplasia, however, published studies describing MRI characteristics of canine prostatic neoplasia are currently lacking. The aims of the current retrospective case series study were to describe MRI findings of the pelvic region in dogs with a histopathologic or cytologic diagnosis of prostatic neoplasia. Retrospective analysis of these images was then performed by a board-certified veterinary radiologist for shared imaging characteristics. The most consistent characteristics were heterogeneous hyperintensity of the tumor on T2-weighted images (10/10) and short tau inversion recovery images (10/10), prostatic capsular margin distortion by the tumor (10/10), cavitations (10/10), complete effacement of the prostatic architecture (9/10), neurovascular bundle (NVB) compression or invasion (9/10), heterogeneous isointensity of the tumor on T1-weighted images (9/10), and strong contrast enhancement of the tumor (8/10). Additional features included an overlying pattern of distorted radiating striations (7/10), regional lymphadenomegaly (5/10), mineralization within the mass (5/10), urinary bladder trigone involvement (6/10), and post-prostatic urethral involvement (7/10). These findings supported the use of MRI as an adjunct imaging modality for diagnosis and therapeutic planning of prostatic neoplasia and including prostatic neoplasia as a likely differential diagnosis for dogs with these MRI characteristics.

Longevity and mortality in cats: A single institution necropsy study of 3108 cases (1989-2019).

Client-owned cats who underwent a post-mortem examination (n = 3,108) at a veterinary medical teaching hospital between 1989 and 2019 were studied to determine longevity and factors affecting mortality. Demographic factors, environmental factors, age, and causes of death were assessed. Sexes included 5.66% intact females, 39.86% spayed females, 6.95% intact males and 47.49% neutered males. 84.2% were mixed breed cats. Age at death was known for 2,974 cases with a median of 9.07 years. Cancer was the most common pathophysiologic cause of death (35.81%) and was identified in 41.3% of cats. When categorized by organ system, mortality was most attributed to multiorgan/systemic (21.72%). Renal histologic abnormalities were noted in 62.84% of cats but was considered the primary cause of death in only 13.06% of cats. Intact female and male cats had significantly shorter lifespans than their spayed or neutered counterparts. FeLV positive status was associated with decreased longevity (P<0.0001) while FIV status was not. This study reports on risk factors associated with mortality and highlights areas of research that may contribute to improved lifespan in cats.

Resolution, recurrence, and chyle redistribution after thoracic duct ligation with or without pericardiectomy in dogs with naturally occurring idiopathic chylothorax.

OBJECTIVE: To document outcomes of thoracoscopic treatment of idiopathic chylothorax (IC) in dogs with and without constrictive pericardial physiology (CPP) and evaluate patterns of chyle flow redistribution after thoracic duct ligation (TDL). ANIMALS: 26 client-owned dogs. PROCEDURES: In this prospective cohort study, echocardiography and cardiac catheterization were performed to document CPP in dogs with IC. Thoracoscopic TDL with pericardiectomy was performed if CPP was present (TDL/P group). Dogs without evidence of CPP underwent thoracoscopic TDL alone (TDL group). Dogs underwent preoperative, immediate postoperative, and 3-month postoperative CT lymphangiography studies when possible. Perioperative morbidity, resolution and late recurrence rates, and long-term outcome were recorded. RESULTS: 17 dogs underwent TDL, and 9 underwent TDL/P. Twenty-five of 26 (96%) survived the perioperative period. One dog died from ventricular fibrillation during pericardiectomy. Resolution rates for TDL and TDL/P were 94% and 88%, respectively (P = .55), with 1 late recurrence occurring in the TDL group in a median follow-up of 25 months (range, 4 to 60 months). On 3-month postoperative CT lymphangiography studies, ongoing chyle flow past the ligation site was demonstrated in 5 of 17 dogs, of which 1 dog developed recurrence at 13 months postoperatively. In 15 of 17 dogs, chylous redistribution after TDL was principally by retrograde flow to the lumbar lymphatic plexus. CLINICAL RELEVANCE: In dogs without evidence of CPP, TDL alone was associated with a very good prognosis for treatment of IC. In the absence of CPP, the additional benefit of pericardiectomy in the treatment of IC is questionable.

Comparative Oncology: Management of Hepatic Neoplasia in Humans and Dogs.

Primary hepatic neoplasia is uncommonly reported in dogs. Hepatocellular carcinoma (HCC) is the most frequent neoplasia identified in dogs and considerable effort has been committed towards identifying definitive and palliative treatment options. HCC is well recognized in humans as a sequelae of liver disease such as hepatitis or cirrhosis, while in dogs a similar link has failed to be fully elucidated. Management of HCC in people may be curative or palliative dependent on staging and transplant eligibility. Despite differences in etiology, there is substantial similarity between treatment options for liver neoplasia in human and veterinary medicine. The below summary provides a comparative discussion regarding hepatic neoplasia in dogs and people with a specific focus on HCC. Diagnosis as well as descriptions of the myriad treatment options will be reviewed.

Percutaneous transvenous coil embolization of congenital intrahepatic portosystemic shunts in small- and toy-breed dogs: 20 cases (2015-2021).

OBJECTIVE: To describe outcomes of small- and toy-breed dogs with a congenital intrahepatic portosystemic shunt (IHPSS) treated with percutaneous transvenous coil embolization (PTCE). ANIMALS: 20 small- and toy-breed dogs with an IHPSS. PROCEDURES: All dogs underwent CT angiography for shunt evaluation as well as PTCE. Medical records were reviewed for pertinent data, and owners and primary veterinarians were contacted for long-term follow-up information. RESULTS: Dogs ranged from 1.5 to 10.0 kg (mean ± SD, 6.32 ± 2.57 kg) in weight. The equipment used to perform PTCE tended to be smaller than that previously described for larger breed dogs. Intra- and postoperative complication rates were 20% (4/20) and 5% (1/20), respectively, and included hypotension, bradycardia, hypercapnia, ventricular premature contractions, hypothermia, and regurgitation. Dogs were discharged a median of 3 days (range, 1 to 3 days) after surgery, and all dogs survived to discharge. Clinical signs resolved in 95% (19/20) of the dogs a median of 21 days after the procedure. One- and 2-year survival rates were 92%. Three dogs had died by the time of data collection; 2 of these dogs died of causes related to the IHPSS 267 and 1,178 days, respectively, after the procedure. CLINICAL RELEVANCE: Percutaneous transvenous coil embolization was a safe and effective option for treatment of IHPSS in small- and toy-breed dogs and offered a minimally invasive alternative to open surgical techniques. Complication and survival rates in this cohort were similar to or better than those reported in previous studies evaluating PTCE and open surgical techniques for treatment of IHPSS in dogs.

Evaluation of the use of a novel bioabsorbable polymer drug-eluting microsphere for transarterial embolization of hepatocellular neoplasia in dogs.

In dogs with non-resectable hepatic neoplasia, treatment options are limited. The objectives of this study were to describe the use of a novel drug-eluting embolic microsphere containing paclitaxel for use during transarterial chemoembolization (TACE), to compare results of liver-specific owner questionnaires and tumor volume pre- and post-TACE, and to measure systemic paclitaxel concentration post-TACE. Client-owned dogs with non-resectable hepatic neoplasia were prospectively enrolled. All owners completed questionnaires validated for the assessment of subjective outcomes in dogs with cancer before the TACE procedure and approximately 4 weeks after the TACE procedure. A CT scan was performed before TACE and 1 month after TACE; results were compared. Blood samples were obtained at specified time points post-TACE to determine systemic paclitaxel concentrations. Seven dogs (median weight: 8.9 kg; range, 4.3-31 kg) were enrolled. TACE was successfully performed in all dogs, and no intra-procedural complications were encountered. Questionnaire scores improved significantly post-TACE. Among the 6 dogs for which full data were available, median pre-TACE tumor volume was 390 cc (range 152-1,484; interquartile range 231-1,139) and median post-TACE tumor volume was 203 cc (range 98-889; interquartile range 151-369), which was significantly (P = .028) lower. All 6 dogs had a reduction in volume at the post-TACE measurement. Mean percent change in tumor volume was -45.6% (95%CI -58.6 to -32.6%). The mean plasma paclitaxel concentration in canine blood peaked at 4 days post-TACE procedure and was 25.7 ng/mL (range = 3.09-110 ng/mL) Median survival time was 629 days (95%CI 18 to upper limit not reached). The use of a novel paclitaxel-eluting microsphere in this cohort of dogs successfully decreased tumor volume significantly after TACE and improved clinical signs. Future investigation into the use of TACE and other similar therapies is warranted due to the promising outcomes noted in this cohort.

Using the canine microbiome to bridge translation of cancer immunotherapy from pre-clinical murine models to human clinical trials.

The microbiome has clearly been established as a cutting-edge field in tumor immunology and immunotherapy. Growing evidence supports the role of the microbiome in immune surveillance, self-tolerance, and response to immune checkpoint inhibitors such as anti PD-L1 and CTLA-4 blockade (1-6). Moreover, recent studies including those using fecal microbial transplantation (FMT) have demonstrated that response to checkpoint immunotherapies may be conferred or eliminated through gut microbiome modulation (7, 8). Consequently, studies evaluating microbiota-host immune and metabolic interactions remain an area of high impact research. While observations in murine models have highlighted the importance of the microbiome in response to therapy, we lack sufficient understanding of the exact mechanisms underlying these interactions. Furthermore, mouse and human gut microbiome composition may be too dissimilar for discovery of all relevant gut microbial biomarkers. Multiple cancers in dogs, including lymphoma, high grade gliomas, melanomas and osteosarcoma (OSA) closely resemble their human analogues, particularly in regard to metastasis, disease recurrence and response to treatment. Importantly, dogs with these spontaneous cancers also have intact immune systems, suggesting that microbiome analyses in these subjects may provide high yield information, especially in the setting of novel immunotherapy regimens which are currently expanding rapidly in canine comparative oncology (9, 10). Additionally, as onco-microbiotic therapies are developed to modify gut microbiomes for maximal responsiveness, large animal models with intact immune systems will be useful for trialing interventions and monitoring adverse events. Together, pre-clinical mechanistic studies and large animal trials can help fully unlock the potential of the microbiome as a diagnostic and therapeutic target in cancer.

Diagnosis, management, and outcome of urethral obstruction secondary to the capsule associated with the artificial urethral sphincter device.

BACKGROUND: Urethral obstruction secondary to artificial urethral sphincter (AUS) implantation is a recognized complication in dogs. However, urethral obstruction secondary to AUS-associated capsule formation has been described rarely. HYPOTHESIS: Describe clinical and diagnostic findings, management, and outcome in 6 dogs with urethral obstruction secondary to AUS-associated capsule formation. ANIMALS: Six client-owned dogs. METHODS: Retrospective study. Medical records between January 1, 2010, and June 30, 2021, were reviewed to identify dogs with urethral obstruction associated with the AUS device. RESULTS: The AUS device was implanted a median of 884 days (range, 20-2457 days) before presentation for urethral obstruction. Median age at time of urethral obstruction was 4.7 years (range, 3.1-8.7 years). Clinical signs at the time of urethral obstruction were stranguria (n = 4), pollakiuria (3), weak urine stream (2), and worsened urinary incontinence (1). In all dogs, the urethra was noted to be stenotic during urethroscopy and positive contrast cystourethrography. All dogs underwent surgery, and a fibrous capsule associated with the AUS was found to be causing urethral stenosis. Resolution of urethral obstruction occurred in all dogs after transection or removal of the capsule. Positive bacterial cultures were obtained from the capsule, AUS, or both in all dogs. Recurrence of urethral obstruction had not occurred in any dog at the time of follow-up. CONCLUSIONS AND CLINICAL IMPORTANCE: Urethral obstruction secondary to capsule formation is an uncommon but clinically important complication associated with use of the AUS. Continued investigation is needed to evaluate this complication more thoroughly, and its possible association with infection.

Untargeted Metabolomics Identify a Panel of Urinary Biomarkers for the Diagnosis of Urothelial Carcinoma of the Bladder, as Compared to Urolithiasis with or without Urinary Tract Infection in Dogs.

Urothelial carcinoma (UC), the most common urologic cancer in dogs, is often diagnosed late because the clinical signs are shared by other non-malignant lower urinary tract disorders (LUTD). The urine-based BRAFV595E test for UC is highly effective only in certain breeds; hence additional non-invasive biomarkers of UC are needed. Here, urine from dogs with UC (n = 27), urolithiasis (n = 8), or urolithiasis with urinary tract infection (UTI) (n = 8) were subjected to untargeted metabolomics analyses, using GC-TOF-MS for primary metabolites, QTOF-MS for complex lipids, and HILIC-QTOF MS for secondary and charged metabolites. After adjusting for age and sex, we identified 1123 known metabolites that were differentially expressed between UC and LUTD. Twenty-seven metabolites were significant (1.5 ≤ log2FC ≤ −1.5, adjusted p-value < 0.05); however, 10 of these could be attributed to treatment-related changes. Of the remaining 17, 6 (hippuric acid, N-Acetylphenylalanine, sarcosine, octanoylcarnitine, N-alpha-methylhistamine, glycerol-3-galactoside) discriminated between UC and LUTD (area under the ROC curve > 0.85). Of the 6 metabolites, only hippuric acid and N-alpha-methylhistamine were discriminatory in both male (n = 20) and female (n = 23) dogs, while sarcosine was an effective discriminator in several breeds, but only in females. Further investigation of these metabolites is warranted for potential use as non-invasive diagnostic biomarkers of dogs with UC that present with LUTD-related clinical signs.