Drug-eluting bead chemoembolization for the treatment of nonresectable hepatic carcinoma in dogs: A prospective clinical trial

Transarterial embolisation in the treatment of persistent haematuria in two dogs with lower urinary tract carcinoma

Two dogs with haematuria and frequent urination were referred to our veterinary hospital. They were diagnosed with lower urinary tract carcinoma based on urine cytology and BRAF mutation testing. Transarterial embolisation was performed because of persistent haematuria. This procedure involved super-selective catheterisation and embolisation of the tumour-feeding arteries using gelatine sponge particles, achieving near stasis. After transarterial embolisation, both patients showed resolution of haematuria within 4 days and a marked reduction in tumour volume after 1 month. However, both patients experienced recurrence of haematuria 4 to 6 weeks after the procedure, leading to a second embolisation being performed for each. Following the second embolisation, the haematuria resolved again. Transarterial embolisation could provide benefits for managing persistent haematuria and provides local tumour control in dogs with lower urinary tract carcinoma.

Hepatic Dearterialization for Nonresectable Liver Tumors in Five Dogs and Two Cats

INTRODUCTION

Some massive or nodular liver tumors can make surgical resection dangerous. Transarterial embolization and chemoembolization recently have been evaluated in dogs and cats, but multinodular or diffuse tumors make selective embolization difficult, impractical, and may require multiple anesthetic events. Hepatic dearterialization in humans has been shown to be safe and sometimes successful in promoting temporary tumor regression.

MATERIALS AND METHODS

Retrospective review of patients with nodular, diffuse, or non-resectable massive liver tumors that underwent transarterial coil embolization of the hepatic artery from the origin of the gastroduodenal artery to the proximal hepatic artery was performed. Data recorded included patient signalment, clinical signs, serum biochemical changes, cross-sectional imaging results, complications, and response to treatment.

RESULTS

Seven patients (five dogs and two cats) underwent transarterial hepatic dearterialization and were included. All patients had increased pretreatment hepatocellular enzyme activities 24 h after surgery. All patients survived to discharge and five were discharged within 24 h after treatment. Two patients experienced mild short-term vomiting and anorexia, one of which required repeat hospitalization. Repeat laboratory testing approximately 6 weeks after treatment indicated decreased ALT and AST activities in 5/6 and 4/5 patients, respectively. Repeat imaging identified tumor regression in 3/4 patients evaluated by computed tomography (CT). Survival time ranged from 50 to 505 days.

CONCLUSION

Hepatic dearterialization should be further investigated as a palliative management option for multinodular and diffuse liver tumors because it may provide a minimally invasive, safe, and palliative option based on the observation that all patients survived to discharge and tumor regression was noted in three animals.

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.

Canine primary liver tumors treated with stereotactic body radiation therapy: A case series

Stereotactic body radiation therapy (SBRT) is an increasingly used alternative treatment option for nonresectable hepatocellular carcinoma (HCC) in people. Comparatively, the publication of SBRT of dogs with HCC is limited. The objective of this retrospective, descriptive case series was to evaluate the clinical outcomes and toxicity data of SBRT in dogs with HCC and imaging-documented primary liver tumors using volumetric-modulated arc therapy delivery at two private institutions. Medical records of 14 dogs treated between 2018 and 2023 were reviewed. All dogs had macroscopic tumors, and 9 of 14 dogs had HCC diagnoses confirmed on cytology or histopathology. The median longest tumor diameter was 5.5 cm. The median percentage of planning target volume relative to liver volume was 27.1%. Most dogs were treated with three daily fractions of 7-7.5 Gy. All dogs completed their radiotherapy protocols. Three of nine HCC dogs experienced partial responses and clinical improvement. Five of nine HCC dogs had stable disease. Overall median survival time was 164 days for nine HCC dogs (range: 93-706 days). One late grade 5 liver and two late grade 3 kidney side effects were reported. One dog received repeated SBRT to the same HCC treatment field, and one dog had two courses of SBRT to bifocal HCC treatment fields, both with no more than grade 2 acute and chronic toxicities.

Therapeutic response and prognostic factors of 14 dogs undergoing transcatheter arterial embolization for hepatocellular masses: A retrospective study

BACKGROUND

Information regarding the therapeutic effect and outcome of transcatheter arterial embolization (TAE) for hepatic masses is limited in veterinary medicine.

HYPOTHESIS/OBJECTIVES

To analyze the therapeutic response, outcome (overall survival), and their predictors in dogs that underwent TAE for primary hepatocellular masses. We hypothesized that larger pre-TAE tumors would be associated with worse outcomes.

ANIMALS

Fourteen client-owned dogs.

METHODS

Retrospective study. Medical records between 1 September 2016 and 30 April 2022 were reviewed to identify dogs treated with TAE for hepatic masses diagnosed as hepatocellular origin by cytological or histopathological examination. Computed tomography images were compared before and after TAE. The univariate Cox proportional hazards test was performed to assess the associations between variables and survival. Univariate linear regression analysis was performed to assess the associations between variables and the tumor reduction percentage: ([post-TAE volume - pre-TAE volume]/pre-TAE volume) × 100.

RESULTS

The median survival time was 419 days (95% confidence interval, 82-474). History of intra-abdominal hemorrhage (P = .03) and pre-TAE tumor volume/body weight (P = .009) were significantly associated with overall survival. The mean reduction percentage was -51% ± 40%. Pre-TAE tumor volume/body weight ratio (cm3 /kg; P = .02, correlation coefficient = 0.704) was significantly correlated with the volume reduction percentage.

CONCLUSIONS

History of intra-abdominal hemorrhage and large pre-TAE tumor volume/body weight ratio could be predictive factors for adverse outcomes after TAE. Pre-TAE tumor volume/body weight ratio could be a predictive factor for therapeutic effect.

Transarterial chemoembolisation for palliative treatment of renal cell carcinoma in two dogs with pulmonary metastasis

Two dogs with anorexia and rapid weight loss were referred to our hospital due to a right renal mass and several pulmonary nodules. Both dogs underwent needle core biopsy of the mass, followed by transarterial chemoembolisation of the renal mass. A catheter was inserted from the femoral artery and advanced into the right renal artery. A suspension of carboplatin (100 mg/m² ) and equivalent lipiodol was administered via the inserted multipurpose catheter. Immediately after, under fluoroscopic guidance, pulse injections of small amounts of gelatin particles (diameter 1 mm) dissolved in iohexol were administered until complete embolisation of the renal artery. Histopathologic diagnosis was renal cell carcinoma in both dogs. Clinical signs improved for 134 and 358 days after transarterial chemoembolisation. In addition, postoperative radiographs demonstrated a decrease in the tumour size. The dogs died 215 and 525 days after the initial evaluation, respectively. As a palliative treatment, transarterial chemoembolisation might help reduce the tumour volume and improve the quality of life in dogs with renal cell carcinoma and distant metastases.

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.

Pharmacokinetic study comparing doxorubicin concentrations after chemoembolization or intravenous administration in dogs with naturally occurring nonresectable hepatic carcinoma

Background

Chemoembolization is a viable treatment option for patients with nonresectable hepatic carcinoma (HC) and may allow delivery of chemotherapeutic drugs with decreased systemic toxicity.

Hypothesis/Objective

Compare the serum concentrations of doxorubicin after chemoembolization or IV administration in the same patient. We hypothesized that locoregional delivery may result in increased tumor chemotherapeutic drug concentrations, reflected by decreased measurable serum drug concentrations. Adverse hematological events were hypothesized to be decreased after locoregional delivery.

Animals

Seventeen client‐owned dogs with incompletely resectable HC.

Methods

Prospective, single‐arm clinical trial. Drug‐eluting bead transarterial chemoembolization was performed to varying levels of blood flow stasis (NO STASIS, STASIS). Intravenous doxorubicin (IVC) subsequently was administered in selected patients. Systemic exposure was quantified by area under the serum doxorubicin concentration time curve (AUC), maximum serum doxorubicin concentration (C_max), and time doxorubicin was last above the limit of quantitation (T_last). Nadir test results after treatments were used to evaluate adverse hematological events.

Results

Thirteen NO STASIS treatments, 15 STASIS treatments, and 9 IVC treatments were performed. Maximum serum doxorubicin concentration, AUC, and T_last were significantly lower when comparing NO STASIS or STASIS to IVC treatments. Of the patients with nadir results available, no adverse hematological events were observed after NO STASIS or STASIS treatments. Two patients developed adverse hematological events after IVC treatment.

Conclusions/Clinical Relevance

Drug‐eluting bead transarterial chemoembolization offers a viable treatment option for patients with incompletely resectable HC with the potential for increased local tumor doxorubicin concentrations, decreased systemic chemotherapeutic exposure, and fewer adverse hematological events.

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.

Risk factors and outcome in dogs with recurrent massive hepatocellular carcinoma: a Veterinary Society of Surgical Oncology case-control study

Local recurrence after surgical excision of canine massive hepatocellular carcinoma (HCC) has been poorly studied in veterinary medicine with scant information published regarding risk factors for and outcome following recurrence. The aim of this case-control study was to describe the time to recurrence, evaluate potential risk factors for recurrence, and report the outcome in dogs with massive HCC. Medical records for 75 dogs who developed recurrence and 113 dogs who did not develop recurrence were reviewed. Statistical analyses were performed to determine risk factors for recurrence as well as the median time to develop recurrence and overall survival time (OS). None of the risk factors evaluated were significant for the development of recurrence. The median time to develop recurrence was 367 days (range: 32-2096 days). There was no significant difference in median OS for dogs who developed recurrence vs. those who did not (851 vs. 970 days). For dogs with recurrent HCC, treatment at recurrence trended toward prolonged OS but was not significantly different from dogs not undergoing treatment at recurrence. There was no significant difference in median OS for dogs with histologically complete vs. incomplete tumor excision (990 vs. 903 days). Though specific risk factors for recurrence were not identified, elevations in liver values were noted in patients with recurrent disease and could act as a noninvasive surveillance tool. Recurrence was noted earlier in dogs who had routine post-operative surveillance (228 vs. 367 days). Routine surveillance for recurrence is recommended especially in dogs where further intervention is possible and should extend beyond 1 year. Patients with massive HCC have a good long-term prognosis regardless of incomplete excision, pulmonary metastasis, or recurrent local disease. This article is protected by copyright. All rights reserved.

A simplified CT-volumetry method for the canine liver

Computed tomographic (CT) liver volumetry using the slice addition technique is an accurate, but a time-consuming method. Commonly used DICOM-viewing software only allows contouring of one area per image, which can be troublesome in the transverse plane as different lobes are separated. In this prospective, experimental, methods comparison study, we aimed to determine if hepatic contouring using sagittal reformatting and a reduced number of images would yield accurate results. Computed tomographic studies were performed in five canine cadavers and reviewed using sagittal reformatting. For each dog, the number of images that included the liver was used to create four stacks with progressively fewer images in which the liver would be contoured, each with the following median number of images: A: 60, B: 31, C: 16, and D: 9. Liver volume was calculated by three observers using the different stacks of images. After CT examination, the cadavers were dissected, the liver was removed, and its volume was determined by water displacement. Single score intraclass correlation coefficient was calculated to assess interobserver agreement. Kruskal-Wallis test was used to compare water displacement and CT-based volumes. There was excellent agreement between observers (intraclass correlation coefficient = 0.957; 95% confidence interval, 0.908-0.982, P < 0.0001). No significant difference was found between the volumes obtained by CT-volumetry using each of the stacks and the volumes obtained by water displacement. Using sagittally reformatted images and hepatic contouring in as few as nine images can be an accurate and simple method for CT-volumetry of the canine liver.

Drug-eluting bead chemoembolization for the treatment of nonresectable hepatic carcinoma in dogs: A prospective clinical trial

Background

Effective treatment options for nonresectable hepatic carcinoma (HC) in dogs are limited.

Hypothesis/Objective

Objectives were to report outcomes, complications, and tumor responses via computed tomography (CT) assessment after drug‐eluting bead transarterial chemoembolization (DEB‐TACE) for nonresectable HC in dogs. The authors hypothesized that major complications would be uncommon and short‐term CT assessment would demonstrate stable disease or partial response.

Animals

Client‐owned dogs (n = 16) with nonresectable HC.

Methods

Prospective, single‐arm clinical trial. Drug‐eluting bead transarterial chemoembolization was performed to varying levels of blood flow stasis. Computed tomography imaging was compared before and approximately 12 weeks after initial treatment.

Results

Drug‐eluting bead transarterial chemoembolization was successfully administered in all attempts. Based on percent change in elliptical tumor volume response (mL), stable disease (8/13; 62%) was the most common outcome followed by partial response (3/13; 23%) and progressive disease (2/13; 15%) with a median of 74 days (range, 39‐125) after initial treatment. Median tumor volume (mL) after DEB‐TACE decreased in volume by 13% (range, 56% decrease to 77% increase). Mild complications consistent with postembolization syndrome occurred after 7/27 (26%) treatments. Major complications occurred after 3/27 (11%) treatments: hepatic abscess/septicemia (2) and cholecystitis/death (1), resulting in treatment‐induced death after 2/27 (7%) treatments. Median survival time after treatment was 337 days (range, 22‐1061). Dogs with a presenting complaint of weight loss (P = .02) had a significantly shorter median survival time (126 days; range, 46‐337) than those dogs without prior history of weight loss (582 days; range, 22‐1061).

Conclusions

Drug‐eluting bead transarterial chemoembolization for nonresectable HC is a feasible procedure, which promoted stable disease or partial response in 85% of dogs in this study sample.