Canine urinary bladder transitional cell carcinoma tumor volume is dependent on imaging modality and measurement technique

Ultrasonographic detection of apex nodules in the urinary bladder of Scottish Terriers

An apex nodule was recently identified in the urinary bladder of Scottish Terriers being screened for bladder cancer at our institution. This prospective, single-center, case series study was performed to better characterize the apex nodule and assess the clinical importance of the nodule. Scottish Terriers ≥6 years of age with no evidence of urinary tract disease underwent urinary tract ultrasonography and urinalysis at 6-month intervals. In dogs with evidence of the apex nodule, ultrasound features such as location, margins, number, echogenicity, size, and shape of the lesion were recorded by a veterinary oncologist and veterinary radiologist. The apex nodule was identified in eight (6%) of 134 dogs in the absence of other detectable bladder disease. Features of the nodules included the following: one nodule per dog, triangular to an oval shape, smooth mucosal covering, well-defined margins, isoechoic to the bladder wall, 2-4 mm at the base, and 4-6 mm protruding into the bladder lumen. In five dogs undergoing multiple ultrasonographic examinations, the nodule did not appear to change over time (up to 3.5 years). Cystoscopy performed in three dogs revealed a column of tissue covered by normal mucosa protruding into the bladder lumen. Histological features consistent with a neoplastic growth were absent. Five dogs remained free of any bladder disease. Three dogs developed urothelial carcinoma at sites distant to the nodule at 8-53 months after the nodule was first observed. Findings indicated that incidental apex nodules could mimic neoplasia and other bladder diseases in Scottish Terriers.

BRAF mutation status and its prognostic significance in 79 canine urothelial carcinomas: A retrospective study (2006-2019)

Urothelial carcinoma (UC) is the most common tumour of the canine urinary bladder. Recently, BRAF mutation testing emerged as a diagnostic option, but its prognostic significance is unknown. This study investigates the relationship between BRAF (variant V595E) mutation status and overall survival in UC-bearing dogs. Seventy-nine patients histologically diagnosed with UC of the bladder and/or urethra between 2006 and 2019 were included in this retrospective single-centre-study. Treatment consisted of meloxicam (n = 39, group 1 'Melox'), mitoxantrone and meloxicam (+/- followed by metronomic chlorambucil; n = 23, group 2 'Chemo') or partial cystectomy followed by meloxicam +/- mitoxantrone (n = 17, group 3 'Sx'). Survival was significantly influenced by treatment (p = .0002) and tumour location (p < .001) in both uni- and multivariable analyses. BRAF mutation was identified in 51 tumours (=64.6%) and had no statistically significant influence on overall survival: MST for BRAF-negative patients 359 versus 214 days for BRAF-positive dogs (p = .055). However, in BRAF-positive dogs, survival depended significantly on type of treatment in univariable analysis: MSTs for groups 1-3 were 151, 244 and 853 days, respectively (p = .006); In BRAF-positive group 2 ('Chemo')-patients, adjuvant metronomic chlorambucil after mitoxantrone more than doubled MST compared to patients receiving mitoxantrone alone (588 vs. 216 days; p = .030). In contrast, MSTs were not significantly different in BRAF-negative patients among the three treatment groups (p = .069). Multivariate analysis of these data was not possible due to group size limitations. This study identified tumour location and treatment type, but not BRAF mutation status, as independent prognostic factors for overall survival.

Computed tomographic staging of dogs with anal sac adenocarcinoma

OBJECTIVES

To describe the CT appearance of anal sac adenocarcinoma lesions in a population of dogs including the relations between primary tumour, and locoregional and distant metastasis.

MATERIALS AND METHODS

Retrospective review of dogs with confirmed anal sac adenocarcinoma and available CT images of the thorax, abdomen and pelvis.

RESULTS

A population of 70 dogs were included in the study. No association was found between anal sac mass size and presence or absence of iliosacral lymph node enlargement. The prevalence of local metastatic disease characterised by iliosacral lymphadenomegaly in this study was 71%, with pulmonary metastases identified in 11% of cases. There were no cases of distant pulmonary metastasis without concurrent locoregional lymphadenomegaly.

CLINICAL SIGNIFICANCE

In our population of dogs local metastatic spread of anal sac adenocarcinoma was common, with a relatively low prevalence of pulmonary metastasis. The study demonstrates the importance of thorough rectal examination and/or imaging to assess the iliosacral lymph centre in this disease irrespective of the size of the anal sac mass.

Deep Learning for Intelligent Recognition and Prediction of Endometrial Cancer

The aim of the study was to investigate the intelligent recognition of radiomics based on the convolutional neural network (CNN) in predicting endometrial cancer (EC). In this study, 158 patients with EC in hospital were selected as the research objects and divided into a training group and a test group. All the patients underwent magnetic resonance imaging (MRI) before surgery. Based on the CNN, the imaging model of EC prediction was constructed according to the characteristics. Besides, the comprehensive prediction model was established through the clinical information and imaging parameters. The results showed that the area under the working characteristic curve (AUC) of the radiomics model and comprehensive prediction model was 0.897 and 0.913 in the training group, respectively. In addition, the AUC of the radiomics model was 0.889 in the test group and that of the comprehensive prediction model was 0.897. The comprehensive prediction model was established through specific imaging parameters and clinical pathological information, and its prediction performance was good, indicating that radiomics parameters could be applied as noninvasive markers to predict EC.

Horizons in Veterinary Precision Oncology: Fundamentals of Cancer Genomics and Applications of Liquid Biopsy for the Detection, Characterization, and Management of Cancer in Dogs

Cancer is the leading cause of death in dogs, in part because many cases are identified at an advanced stage when clinical signs have developed, and prognosis is poor. Increased understanding of cancer as a disease of the genome has led to the introduction of liquid biopsy testing, allowing for detection of genomic alterations in cell-free DNA fragments in blood to facilitate earlier detection, characterization, and management of cancer through non-invasive means. Recent discoveries in the areas of genomics and oncology have provided a deeper understanding of the molecular origins and evolution of cancer, and of the "one health" similarities between humans and dogs that underlie the field of comparative oncology. These discoveries, combined with technological advances in DNA profiling, are shifting the paradigm for cancer diagnosis toward earlier detection with the goal of improving outcomes. Liquid biopsy testing has already revolutionized the way cancer is managed in human medicine - and it is poised to make a similar impact in veterinary medicine. Multiple clinical use cases for liquid biopsy are emerging, including screening, aid in diagnosis, targeted treatment selection, treatment response monitoring, minimal residual disease detection, and recurrence monitoring. This review article highlights key scientific advances in genomics and their relevance for veterinary oncology, with the goal of providing a foundational introduction to this important topic for veterinarians. As these technologies migrate from human medicine into veterinary medicine, improved awareness and understanding will facilitate their rapid adoption, for the benefit of veterinary patients.

Presumptive malignant transformation of chronic polypoid cystitis into an apical transitional cell carcinoma without BRAF mutation in a young female dog

A 3-year-old spayed female English Springer Spaniel was presented twice 4 months apart for investigation of hematuria and pollakiuria without urinary tract infection. Both ultrasound examinations identified a stable craniodorsal bladder wall thickening. The first cystoscopic biopsy samples indicated lymphoplasmacytic cystitis and the second polypoid cystitis. The dog was represented 8 months later for recurrent clinical signs despite medical management. Although the ultrasound examination showed stable disease, repeat cystoscopic biopsy identified transitional cell carcinoma (TCC), confirmed on tissue removed by partial cystectomy. No BRAF mutation was ever detected in urine or tissue samples. To our knowledge, this case represents the first report of presumptive malignant transformation of polypoid cystitis into an apical TCC in a dog. Dogs with polypoid cystitis should be followed closely and surgical management considered if rapid resolution is not achieved with medical management.

Treatment of genitourinary carcinoma in dogs using nonsteroidal anti-inflammatory drugs, mitoxantrone, and radiation therapy: A retrospective study

Background

Locoregional tumor control and prolonged survival for dogs with genitourinary carcinoma (CGUC) reportedly are achievable using treatment with radiotherapy (RT) with or without adjunctive chemotherapy and nonsteroidal anti‐inflammatory drugs (NSAIDs).

Objectives

To characterize event‐free and overall survival after treatment of CGUC using NSAIDs, mitoxantrone (MTX), and a standardized RT protocol (57 Gy in 20 fractions).

Animals

Fifty‐one client‐owned dogs treated between 2008 and 2017.

Methods

Dogs were retrospectively categorized into treatment groups: (a) first‐line concurrent chemoradiotherapy (≥1 dose of MTX started within 1 month of RT); (b) first‐line chemotherapy (MTX administered for >1 month before RT without tumor progression); (c) RT as a salvage procedure (MTX, surgery or both with subsequent locoregional tumor progression before RT). Treatment‐induced toxicoses, event‐free survival (EFS), and overall survival times (OSTs) were recorded. The influence of demographics, staging, and treatment‐related factors on survival was assessed using Cox proportional hazards modeling.

Results

Median EFS and OST for all dogs were 260 and 510 days with no significant differences among groups 1 (n = 39), 2 (n = 4), and 3 (n = 8). Both EFS and OST were shorter in dogs with moderate to severe clinical signs (P < .001 and P < .001, respectively); OST was shorter in dogs with prostatic involvement (P = .02). Permanent urinary incontinence developed in 16 dogs (31%) at a median of 70 days postirradiation; other toxicoses were mild and self‐limiting.

Conclusions and Clinical Importance

Mild clinical signs and lack of prostate involvement were associated with favorable prognosis for survival. Client education regarding the risk of urinary incontinence is warranted.

CT imaging features of the normal parathyroid gland in the dog

OBJECTIVE

Aim of our prospective pilot study was to assess the feasibility of computed tomography (CT) to visualize the normal parathyroid gland in dogs and provide a description of its CT appearance.

MATERIAL AND METHODS

A total of 25 dogs, which received CT imaging including the neck region for diseases unrelated to the thyroid or parathyroid glands, were enrolled. Inclusion criteria were a normal physical examination, an unremarkable complete blood count and serum chemistry profile. Pre and post contrast CT images were acquired using a 16-slice helical scanner with an 18 cm field of view, 1 mm slice thickness and a 512 × 512 matrix. Post contrast images were obtained 30-45 seconds following contrast medium injection (early venous phase). CT-images were independently reviewed by 2 radiologists. Visibility of the parathyroid gland was recorded and inter-observer agreement was calculated. For all visualized parathyroid glands the following parameters were assessed: size, density in Hounsfield units (HU) on pre and post contrast images, density of the thyroid gland and border definition (excellent, moderate, poor).

RESULTS

Only 20 respectively 25 parathyroid glands could be visualized by the 2 observers. The number did not vary between pre and post contrast images. The inter-observer agreement for the identification was fair (κ = 0.40). Length, width and height (mean ± standard deviation) of the parathyroid gland were 4.2 × 2.5 × 2.9 mm ± 1.3 × 0.8 × 1.0 mm. The density was 39.7 ± 20.6 HU on pre contrast images and 103.1 ± 47.1 HU on post contrast images, thus the organ was hypoattenuating compared to the thyroid gland on pre (166.7 ± 34.3 HU) and post contrast (234.0 ± 60.1 HU) images.

CONCLUSION

This study offers the first description of the CT appearance of the presumed normal canine parathyroid gland. However, the overall visibility was poor.

CLINICAL RELEVANCE

Despite the overall poor visibility of the parathyroid gland it was occasionally visible and its CT dimensions were larger as described for ultrasound in this group of dogs, which showed no clinical signs of hyperparathyroidism. Thus, visibility of the parathyroid gland on CT may not necessarily imply parathyroid disease. However, further research is necessary.

Quantitative analysis of the BRAF V595E mutation in plasma cell-free DNA from dogs with urothelial carcinoma

Circulating tumor DNA (ctDNA), which carries tumor-specific mutations, is an emerging candidate biomarker for malignancies and for monitoring disease status in various human tumors. Recently, BRAF V595E mutation has been reported in 80% of dogs with urothelial carcinoma. This study investigates the BRAF V595E allele concentration in circulating cell-free DNA (cfDNA) and assesses the clinical significance of BRAF-mutated ctDNA levels in canines with urothelial carcinoma. A total of 15 dogs with urothelial carcinoma were included. cfDNA concentration was measured using a real-time polymerase chain reaction (PCR) of the LINE-1 gene. To measure the concentration of the mutated BRAF gene in cfDNA, allele-specific real-time PCR with a locked nucleic acid probe was performed. BRAF mutations were detected in 11 (73%) of the 15 tested tumor samples. BRAF-mutated ctDNA concentrations were significantly higher in dogs with the BRAF mutation (14.05 ± 13.51 ng/ml) than in wild-type dogs (0.21 ± 0.41 ng/ml) (p = 0.031). The amount of BRAF-mutated ctDNA in plasma increased with disease progression and responded to treatment. Our results show that BRAF-mutated ctDNA can be detected using allele-specific real-time PCR in plasma samples of canines with urothelial carcinoma with the BRAF V595E mutation. This ctDNA analysis may be a potentially useful tool for monitoring the progression of urothelial carcinoma and its response to treatment.

Use of transrectal ultrasonography for assessment of the size and location of prostatic carcinoma in dogs

OBJECTIVE

To evaluate the use of transrectal ultrasonography (TRUS) for the assessment of prostatic tumors in dogs and to compare results for TRUS with results for other imaging modalities.

ANIMALS

10 client-owned male dogs.

PROCEDURES

Client-owned dogs identified with prostatic carcinoma were enrolled. Fluoroscopy, transabdominal ultrasonography (TAUS), TRUS, and MRI were performed on all dogs. Tumor measurements, urethral penetration (identification of abnormal tissue within the urethral lumen), and tumor extension into the urinary tract were recorded for all imaging modalities. Agreement between results for MRI (considered the criterion-referenced standard) and results for other modalities were compared.

RESULTS

Median body weight of the 10 dogs was 26.3 kg (range, 9.4 to 49.5 kg). No complications were encountered during or after TRUS. Significant moderate to good agreements (intraclass correlation coefficients, 0.60 to 0.86) among TAUS, TRUS, fluoroscopy, and MRI were identified for tumor length and height. Assessments of urethral penetration and tumor extension into the bladder with TRUS did not differ significantly from those made with MRI and were superior in terms of absolute agreement with MRI when compared with those for TAUS.

CONCLUSIONS AND CLINICAL RELEVANCE

TRUS was successfully and safely used to evaluate prostatic carcinoma in dogs. There was moderate to good agreement with MRI results for tumor height and length measurements, and TRUS was found to be superior to TAUS for some assessments. Transrectal ultrasonography can be considered an adjunctive imaging modality for the performance of prostatic interventional procedures or assessment of response to treatment.

CT imaging features of canine thymomas

Canine thymomas have been evaluated based on clinical features, treatment options, surgical excision, and outcomes with limited information on specific CT features. The objective of this retrospective, descriptive, cross-sectional study was to describe the CT characteristics of confirmed thymomas and to compare these imaging features to outcome. A total of 22 dogs met the inclusion criteria of histologically confirmed thymomas with concurrent CT imaging. Tumor size varied widely ranging from small and well-circumscribed to large and invasive. Delayed-phase, contrast-enhanced CT studies were best for determining the degree of contrast enhancement in tumors. Of these, 19 of 22 masses had heterogeneous enhancement and three of 22 masses had homogeneous enhancement. Vascular invasion was present in seven of 22 cases. Larger tumors were associated with vascular invasion (height: P = .04; width and volume: P = .02). On precontrast CT, larger tumors (16/21) were heterogeneous and cystic, with smaller tumors (5/21) being more homogeneous (all values P < .05). A larger size was associated with recurrence in fully resected masses (height: P = .03), but not a shorter outcome (P > .3 for all size dimensions). Postoperative complications and incomplete tumor resection were associated with shorter outcome (both values P < .01). Metastasis was confirmed in four cases. There were six cases with lymphadenopathy noted on CT; five of the six cases did not have evidence of metastasis. Larger tumors were more likely to be cystic and associated with vascular invasion.

Ultrasound characteristics of feline urinary bladder transitional cell carcinoma are similar to canine urinary bladder transitional cell carcinoma

Feline transitional cell carcinoma (TCC) is a rare neoplasia of cats with an estimated prevalence of 0.18%. Cats with TCC share clinical signs with common pathologies like feline idiopathic cystitis or urinary tract infections. Nonspecific clinical signs include hematuria, pollakiuria, or stranguria. The literature lacks a feline-specific ultrasound description of TCC. The aim of this multicenter retrospective descriptive study was to report ultrasound findings of a collection of feline TCC and then assess if feline TCC and canine TCC have similar ultrasound appearances. It was hypothesized that the ultrasound characteristics would be similar between feline and canine TCC. Ultrasound studies were assessed for tumor shape, number of isolated mural masses, location within the bladder, presence of Doppler signal, echogenicity of urine, mineralization within the mass, extension of the mass into the proximal urethra or ureters, urethral/ureteral obstruction, pyelectasia, and sublumbar lymphadenopathy. Feline studies were compared to 20 cases of confirmed canine TCC. A total of 20 cats with histologically or cytologically confirmed diagnosis of TCC were included. Feline and canine TCC had similarities when viewed using ultrasound. Statistically significant differences were identified for location of the bladder mass (cats were more likely to be mid-body vs trigonal in dogs, P = .011) and urethral extension of the tumor was less likely in cats than dogs (P = .0436). Based on this sample of 20 cats, feline TCC was most commonly a singular, broad-based mass within the mid-body or apex of the urinary bladder.

Urologic Oncology

Primary renal tumors are an uncommon diagnosis in small animals. Presentation, treatment, and prognosis depend on tumor type. Surgery with or without chemotherapy are the mainstays of treatment. Transitional cell carcinoma is the most common tumor of the urinary system. Clinical signs include hematuria, stranguria, and pollakiuria. Metastatic disease can develop over time within medial iliac lymph nodes, lungs, and vertebrae. Treatment of transitional cell carcinoma centers on chemotherapy with mitoxantrone, vinblastine, or carboplatin. Other agents used with success, include toceranib phosphate and chlorambucil. Interventional surgery, such as stenting and laser ablation, is used in a palliative setting addressing urinary obstruction.