FDG PET/CT IMAGING IN CANINE CANCER PATIENTS

2‐Deoxy‐2‐[¹⁸F]fluoro‐d ‐glucose positron emission tomography/computed tomography (FDG PET/CT) is becoming increasingly available as an imaging modality in veterinary medicine. The purpose of this study was to report semiquantitative standard uptake values (SUV) of malignant and nonmalignant tissues and organs in canine cancer patients. FDG PET/CT was performed in 14 dogs including, nine mesenchymal tumors, four carcinomas, and one incompletely excised mast cell tumor. A generally higher FDG uptake was observed in carcinomas relative to sarcomas. Maximum SUV of carcinomas ranged from 7.6 to 27.0, and for sarcomas from 2.0 to 10.6. The FDG SUV of several organs and tissues, including regional brain uptake is reported, to serve as a reference for future FDG PET studies in canine cancer patients. Several potential pitfalls have been recognized in interpretation of FDG PET images of human patients, a number of these were also observed in this study.     

Equine odontogenic tumors: Clinical presentation,CT findings,and outcome in 11 horses

Odontogenic tumors present as locally invasive, slow growing, firm swellings on the face. They are rare in all species and are characterized histologically by the degree of differentiation and dental tissue of origin. Radiographic appearance is not pathognomonic for these lesions. Computed tomographic (CT) examination allows exact determination of tumor extension and aggressiveness. The objectives of this retrospective, case series study were to describe the clinical presentation, CT characteristics, and outcome in horses with histologically confirmed odontogenic tumors, and to identify imaging features suggestive of individual types of tumors. Four ameloblastomas, two ameloblastic carcinomas, three ameloblastic fibromas, and two complex odontomas were included. All but one complex odontoma presented as a single mass. All tumors were associated with maxillary or mandibular bone expansion, alveolar and cortical bone lysis, and cortical bone thinning. The majority also had cortical bone thickening and periosteal proliferation. All tumors contained some degree of mineral attenuation, although only the complex odontomas contained enamel attenuation allowing differentiation from other types of odontogenic tumors in this study. Ameloblastomas were found to have variable CT characteristics likely due to the sub‐groups of ameloblastomas. Both ameloblastic carcinomas contained a mixture of mineralized and soft tissue attenuating material whereas ameloblastic fibromas were mainly composed of soft tissue attenuating material. Computed tomographic characteristics of odontogenic tumors generally indicate that they are expansile, aggressive tumors and can occur in a wide range of ages. Further investigation is needed to elucidate differences between each type of equine odontogenic tumor.     

COMPUTED TOMOGRAPHIC FEATURES OF CANINE NONPARENCHYMAL HEMANGIOSARCOMA

The purpose of this retrospective study was to describe pre‐ and postcontrast computed tomographic (CT) characteristics of confirmed nonparenchymal hemangiosarcoma in a group of dogs. Medical records were searched during the period of July 2003 and October 2011 and dogs with histologically confirmed nonparenchymal hemangiosarcoma and pre‐ and postcontrast CT images were recruited. Two observers recorded a consensus opinion for the following CT characteristics for each dog: largest transverse tumor diameter, number of masses, general tumor shape, character of the tumor margin, precontrast appearance, presence of dystrophic calcification, presence of postcontrast enhancement, pattern of postcontrast enhancement, presence of regional lymphadenopathy, and presence of associated cavitary fluid. A total of 17 dogs met inclusion criteria. Tumors were located in the nasal cavity, muscle, mandible, mesentery, subcutaneous tissue, and retroperitoneal space. Computed tomographic features of nonparenchymal hemangiosarcoma were similar to those of other soft tissue sarcomas, with most tumors being heterogeneous in precontrast images, invasive into adjacent tissue, and heterogeneously contrast enhancing. One unexpected finding was the presence of intense foci of contrast enhancement in 13 of the 17 tumors (76%). This appearance, which is not typical of other soft tissue sarcomas, was consistent with contrast medium residing in vascular channels. Findings indicated that there were no unique distinguishing CT characteristics for nonparenchymal hemangiosarcoma in dogs; however, the presence of highly attenuating foci of contrast enhancement may warrant further investigation in prospective diagnostic sensitivity and treatment outcome studies.     

PROGNOSTIC SIGNIFICANCE OF TUMOR HISTOLOGY AND COMPUTED TOMOGRAPHIC STAGING FOR RADIATION TREATMENT RESPONSE OF CANINE NASAL TUMORS

Prognostic significance of tumor histology and four computed tomography (CT) staging methods was tested retrospectively in dogs from three treatment centers that underwent intent-to-cure-radiotherapy for intranasal neoplasia. Disease-free and overall survival times were available for 94 dogs. A grouping of anaplastic, squamous cell, and undifferentiated carcinomas had a significantly shorter median disease-free survival (4.4 mo) than a grouping of all sarcomas (10.6 months). Disease-free survivals were not significantly different, when all carcinomas were compared with all sarcomas. The published original and modified WHO staging methods did not significantly relate to either survival endpoint. A modified human maxillary tumor staging system previously applied to canine nasal tumors was prognostically significant for both survival endpoints; a further modified version of that CT-based staging system resulted in improved significance for both survival endpoints. Dogs with unilateral intranasal involvement without bone destruction beyond the turbinates on CT, had longest median survival (23.4 months); CT evidence of cribriform plate involvement was associated with shortest median survival (6.7 months). Combining CT and histology statistically improved prognostic significance for both survival endpoints over the proposed CT staging method alone. Significance was lost when CT stages were collapsed to 相似文献   

COMPUTED TOMOGRAPHIC FINDINGS IN 24 DOGS WITH LIPOSARCOMA

Computed tomography (CT) continues to become more widely available for assessment of tumors in dogs, yet there are no studies describing the CT appearance of canine liposarcomas. In this retrospective, multicenter study, CT images of dogs with histologically confirmed liposarcomas were reviewed for size, location, attenuation, contrast enhancement, border definition, internal homogeneity, local infiltration, and mineralization. A total of 24 dogs with 26 liposarcomas were sampled. Mean attenuation was +15.2 (SD = 22.3) Hounsfield units (HU) with a range of –36 to +47.5 HU based on representative regions of interest. Twenty tumors (77%) contained focal areas of fat attenuation. All masses enhanced with contrast medium administration, which is distinct from what has been reported previously in infiltrative lipomas. Other CT features associated with canine liposarcomas included heterogeneous internal attenuation (81%) and lack of a clearly defined capsule (38%) suggesting infiltration of local structures. Six tumors (23%) had foci of mineralization. Findings from the current study indicated that liposarcoma should be considered as a differential diagnosis for mixed‐attenuation, contrast‐enhancing masses in dogs that contain at least one focus of fat attenuation on precontrast images; however, presence of foci of fat attenuation was not a necessary finding for the diagnosis of canine liposarcoma.     

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

OBJECTIVE: To determine outcome associated with cutaneous tumors treated via intratumoral chemotherapy with cisplatin and identify risk factors affecting local tumor control and complications in equidae. DESIGN: Retrospective case series. ANIMALS: 573 equidae with 630 cutaneous tumors. PROCEDURES: Medical records of horses, mules, donkeys, and ponies with cutaneous tumors treated via intratumoral chemotherapy with cisplatin were analyzed. RESULTS: 549 horses, 13 mules, 8 donkeys, and 3 ponies with 630 histologically confirmed cutaneous tumors were included. Tumors included sarcoids (n = 409), squamous cell carcinomas (151), soft tissue sarcomas (28), cutaneous lymphomas (26), and melanomas (16). Overall cure rate, defined as local control at 4 years, was 93.3%. For all tumor stages combined, cure rates after 1 course of treatment were 96.3% for sarcoids, 96% for lymphomas, 88% for squamous cell carcinomas, 85% for soft tissue sarcomas, and 81% for melanomas. Treatment protocol, tumor stage, and prior treatment were significant prognostic factors for tumor control. Treatment efficacy was lower for large tumors, those with gross postoperative residual disease, and those that had been treated previously with other modalities. Treatment was well tolerated. Local reactions were more likely to occur and to be more severe after the third and fourth treatment sessions. CONCLUSIONS AND CLINICAL RELEVANCE: Results confirmed the value of intratumoral chemotherapy with cisplatin for treatment of cutaneous tumors in equidae.The results cannot be extrapolated to other formulations of cisplatin or other protocols that might be used.     

Prostatic Perfusion in the Dog Using Contrast-Enhanced Doppler Ultrasound

Ultrasonography has become the imaging modality of choice for evaluation of the prostate gland in the dog. Unfortunately, despite providing excellent images, it may be difficult to differentiate the common canine prostatic diseases with ultrasound because many have a similar ultrasonographic appearance. Real-time contrast-enhanced ultrasound was used to monitor and characterise the normal perfusion pattern and perfusion dynamics of the canine prostate gland when using a micro bubble contrast agent. In all contrast studies, the prostatic artery, entered the prostate gland on the dorso-lateral surface then tunnelled into the prostatic capsule and branched into many small parenchymal arteries which were directed medially towards the urethra to supply the body of the prostate gland. The flow of the contrast medium into the prostatic parenchyma was visible after 15 s. During the wash-in phase, there was an homogenous enhancement of the prostatic parenchyma. During the wash-out phase, an homogenous decrease of the echogenicity was visible in all cases.     

COMPUTED TOMOGRAPHY AND POSITIVE CONTRAST COMPUTED TOMOGRAPHIC ARTHROGRAPHY OF THE CANINE SHOULDER: NORMAL ANATOMY AND EFFECTS OF LIMB POSITION ON VISIBILITY OF SOFT TISSUE STRUCTURES

Soft tissue injuries of the shoulder are an important cause of forelimb lameness in dogs. The objectives of this canine cadaver study were to describe normal anatomy of shoulder soft tissue structures using computed tomography (CT) and computed tomographic arthrography (CTA) and to determine the effects of positioning on visualization of shoulder soft tissue structures. Thirteen forelimbs were removed from eight canine cadavers. Two forelimbs were used for contrast dose optimization. For the remaining 11 forelimbs, shoulder CT and CTA were performed using three defined joint angles (140°, 90°, and 70°). For three forelimbs, CT and CTA images were compared with frozen anatomic sections to describe normal anatomy. Ten forelimbs were used for analysis of positioning effects. Soft tissue structures evaluated were the joint capsule, cartilage, ligaments, tendons, and muscles. A visual assessment score was assigned to each structure using a consensus of two observers. The range and mode of scores were calculated and compared for each modality and limb position. The shoulder joint capsule and medial and lateral glenohumeral ligaments were completely visible with CTA. All tendons and muscles were visualized in all the examinations except for the teres minor muscle tendon and the coracobrachialis muscle, which were not visible on all scans. Positioning the limb in an extended position significantly improved visualization of most soft tissue shoulder structures. Shoulder cartilage was best seen with CTA and with neutral or flexed positioning of the shoulder. Findings indicated that both CT and CTA are feasible imaging techniques for visualization of soft tissue structures of the canine shoulder.     

DYNAMIC CT MEASUREMENT OF CONTRAST MEDIUM WASHIN KINETICS IN CANINE NASAL TUMORS

Tumor oxygenation affects the biologic behavior of a tumor and also its radiation response. Decreased tumor oxygenation has been associated with an aggressive phenotype and with decreased local tumor control following irradiation. Thus, measurement of oxygenation may be useful for pretreatment evaluation of a tumor. Many methods for assessing tumor oxygenation are available but most are invasive. There is a need for a non-invasive measure of oxygenation, or a surrogate for oxygenation. Measurement of perfusion has been suggested as a substitute for measurement of oxygenation. The use of washin kinetics of iodinated contrast medium to estimate perfusion has been shown to be related to radiation response of human carcinomas. We quantified the washin kinetics of iodinated contrast medium using dynamic CT in 9 dogs. All dogs had a malignant nasal tumor and perfusion was quantified at two sites in each tumor to evaluate intratumoral variation in perfusion. Dogs were given an intravenous bolus injection of contrast medium and arterial and tumor washin kinetics quantified using a helical CT scanner. Perfusion was estimated from these data using previously validated methods. Eight of the 9 dogs received definitive radiation therapy and perfusion was quantified a second time in these 8 dogs midway through irradiation. Pretreatment perfusion varied between dogs by a factor of 16.9. Between dog variation in perfusion was subjectively greater than within tumor variation based on comparison of two intratumoral regions. Changes in perfusion in individual dogs during irradiation were observed, but no identifiable pattern of perfusion alteration was detected. Measurement of perfusion in canine nasal tumors using dynamic CT is possible and further study of this parameter as it relates to radiation response is reasonable.     

Matrix metalloproteinase-2 and -9 involvement in canine tumors

Matrix metalloproteinases (MMPs) are a family of enzymes implicated in the degradation and remodeling of extracellular matrix and in vascularization. They are also involved in pathologic processes such as tumor invasion and metastasis in experimental cancer models and in human malignancies. We used gelatin zymography and immunohistochemistry to determine whether MMP-2 and MMP-9 are present in canine tumors and normal tissues and whether MMP production correlates with clinicopathologic parameters of prognostic importance. High levels of pro-MMP-9, pro-MMP-2, and active MMP-2 were detected in most canine tumors. Significantly higher MMP levels were measured in canine tumors than in nontumors, malignancies had higher MMP levels than benign tumors, and sarcomas had higher active MMP-2 than carcinomas. Cartilaginous tumors produced higher MMP levels than did nonsarcomatous malignancies, benign tumors, and normal tissues, and significantly greater MMP-2 than osteosarcomas and fibrosarcomas. Pro-MMP-9 production correlated with the histologic grade of osteosarcomas. The 62-kd form of active MMP-2 was detected only in high-grade, p53-positive, metastatic malignancies. Zymography proved to be a sensitive and quantitative technique for the assessment of MMP presence but has the limitation of requiring fresh tissue; immunohistochemistry is qualitative and comparatively insensitive but could be of value in archival studies. MMP presence was shown in a range of canine tumors, and their link to tumor type and grade was demonstrated for the first time. This study will allow a substantially improved evaluation of veterinary cancer patients and provides baseline information necessary for the design of clinical trials targeting MMPs.     

Contrast harmonic imaging characterization of canine splenic lesions

Background: Although B-mode ultrasound is very sensitive for the detection of splenic lesions, its specificity is low. Contrast harmonic imaging is used successfully to differentiate benign from malignant liver lesions in humans and dogs.
Hypothesis: Contrast harmonic imaging could be useful to differentiate benign and malignant splenic lesions in dogs.
Animals: Sixty dogs (clinical patients) with splenic abnormalities detected during abdominal ultrasonography.
Methods: A prospective study was performed with a Philips ATL 5000 unit for contrast pulse inversion harmonic imaging (mechanical index: 0.08, contrast medium: SonoVue). Perfusion was assessed subjectively and quantitatively.
Results: Cytology or histology identified 27 benign (hyperplasia, extramedullary hematopoiesis, hematoma) and 29 malignant (hemangiosarcoma, malignant lymphoma, malignant histiocytosis, mesenchymal tumors without classification, mast cell tumors, and others) lesions and 4 normal spleens. Except for 1 benign nodule, extensive to moderate hypoechogenicity was only seen in malignant lesions during wash-in, at peak enhancement, and during wash-out ( P = .0001, odds ratios: 37.9 [95% CI 4.5–316.5], 66.4 [95% CI 8.0–551.1], and 36.9 [95% CI 4.4–308.4]). Although all but 1 benign lesion enhanced well and were mildly hypo-, iso-, or hyperechoic in comparison with the normal spleen during all blood pool phases, marked enhancement occurred both in benign as well as in malignant splenic lesions. Quantitative perfusion values did not differ significantly between benign and malignant lesions.
Conclusions and Clinical Importance: Moderate to extensive hypoechogenicity clearly identifies canine splenic malignant lesions. In nodules with marked enhancement, contrast harmonic ultrasound is of limited value and histology is needed.     

INTRAARTERIAL CONTRAST-ENHANCED COMPUTED TOMOGRAPHY OF THE EQUINE DISTAL EXTREMITY

A technique for regional delivery of contrast medium to the foot of the horse to increase the diagnostic utility of computed tomography (CT) for the characterization of soft tissue structures within the hoof capsule was developed. An intraarterial catheter was placed under ultrasound guidance into the medial palmar artery at the level of the carpus to facilitate a steady-state infusion of iodinated contrast medium. Two 5 mm collimated contiguous acquisition CT scans were performed in 10 horses without lameness or radiographic evidence of distal sesamoid bone degeneration. CT examination was performed before and during regional arterial infusion of iodinated contrast medium administered at a rate of 2 ml/s. Cross-sectional area and mean pre- and post-contrast attenuation of the deep digital flexor tendon and the collateral ligaments of the distal interphalangeal joint were quantified from CT images. Soft tissue anatomy of the foot was also qualitatively characterized from pre- and postcontrast images. Catheterization was successful and without complication in all horses. The evaluated tendons and ligaments were clearly visible and had a small (8-20 Hounsfield Unit) but significant (P < 0.05, paired t-test) increase in attenuation during the steady-state infusion of contrast medium. This study should enhance the diagnostic potential of CT by providing baseline quantitative data for comparison with horses affected with soft tissue injuries in the distal extremity causing lameness that is alleviated with a palmar digital nerve block.     

COMPUTED TOMOGRAPHY FEATURES OF MIDDLE EAR CHOLESTEATOMA IN DOGS

We describe the computed tomography (CT) findings in 11 dogs with middle ear cholesteatoma. The cholesteatoma appeared as an expansile tympanic cavity mass with a mean attenuation value of 55.8±4.2 Hounsfield units. There was no appreciable contrast enhancement of the tympanic bulla contense but ring enhancement was seen in four dogs. Due to the slow progressive growth, the lesion causes severe bone changes at the contour of the tympanic bulla, including osteolysis, osteoproliferation and osteosclerosis, expansion of the tympanic cavity, and sclerosis or osteoproliferation of the ipsilateral temporomandibular joint and paracondylar process. Cholesteatoma can cause lysis of the petrosal part of the temporal bone, leading to intracranial complications. Although not definitive, CT provides useful information for distinguishing a middle ear cholesteatoma from otitis media and neoplasia. In otitis media, enlargement of the tympanic cavity is not routinely observed. In tumors that primarily affect the middle or inner ear, the predominant signs are lysis of the contour of the tympanic bulla or the petrosal part of the temporal bone, soft tissue swelling around the middle ear and marked contrast enhancement. In tumors that arise from the external ear, a soft tissue mass is visible within the external acusticus meatus, and the middle ear is only involved secondarily.     

COMPUTED TOMOGRAPHIC FEATURES OF PHARYNGEAL NEOPLASIA IN 25 DOGS

Computed tomography (CT) is commonly used to investigate head tumors in dogs, however little information is available for lesions of the pharyngeal area. The purpose of this multicentric, retrospective, cross‐sectional study was to describe the CT findings in a sample of dogs with pathologically confirmed pharyngeal neoplasia and determine whether any CT features allowed differentiation of tumor type. Location of lesions, size and shape, margins, relationship with surrounding structures and vessels, attenuation characteristics and enhancement pattern, regional lymph node changes, and presence of metastasis were recorded by three observers (1 DECVDI). The effect of final diagnosis on each CT feature was tested. A total of 25 dogs were included: 15 with carcinomas, five sarcomas, four melanomas, and one lymphoma. The oropharynx and laryngopharynx were more frequently involved. Among tumor groups, lesions were of similar size, irregularly shaped, had ill‐defined margins, and had moderate‐to‐marked heterogeneous contrast enhancement. Lysis of hyoid bones was recorded in two carcinomas and infiltration of the lingual artery occurred in one case. Marked medial retropharyngeal lymphoadenomegaly was recorded in 11 of 14 carcinomas, in all sarcomas and in two of four melanomas. The single lymphoma case showed ill‐defined thickening of the oropharyngeal and laryngeal wall with retropharyngeal and mandibular lymphadenomegaly. Lung metastases were found in two of five sarcomas and two of four melanomas. Findings from the current study did not support the hypothesis that CT features could be used to predict pharyngeal tumor type in dogs. However, CT was helpful for determining mass extension, lymph node involvement, and distant metastatic spread.     

PROSPECTIVE COMPARISON OF TUMOR STAGING USING COMPUTED TOMOGRAPHY VERSUS MAGNETIC RESONANCE IMAGING FINDINGS IN DOGS WITH NASAL NEOPLASIA: A PILOT STUDY

Identification of nasal neoplasia extension and tumor staging in dogs is most commonly performed using computed tomography (CT), however magnetic resonance imaging (MRI) is routinely used in human medicine. A prospective pilot study enrolling six dogs with nasal neoplasia was performed with CT and MRI studies acquired under the same anesthetic episode. Interobserver comparison and comparison between the two imaging modalities with regard to bidimensional measurements of the nasal tumors, tumor staging using historical schemes, and assignment of an ordinal scale of tumor margin clarity at the tumor‐soft tissue interface were performed. The hypotheses included that MRI would have greater tumor measurements, result in higher tumor staging, and more clearly define the tumor soft tissue interface when compared to CT. Evaluation of bone involvement of the nasal cavity and head showed a high level of agreement between CT and MRI. Estimation of tumor volume using bidimensional measurements was higher on MRI imaging in 5/6 dogs, and resulted in a median tumor volume which was 18.4% higher than CT imaging. Disagreement between CT and MRI was noted with meningeal enhancement, in which two dogs were positive for meningeal enhancement on MRI and negative on CT. One of six dogs had a higher tumor stage on MRI compared to CT, while the remaining five agreed. Magnetic resonance imaging resulted in larger bidimensional measurements and tumor volume estimates, along with a higher likelihood of identifying meningeal enhancement when compared to CT imaging. Magnetic resonance imaging may provide integral information for tumor staging, prognosis, and treatment planning.     

Intentional marginal excision of canine limb soft tissue sarcomas followed by radiotherapy

Objectives: To evaluate the outcome in a group of dogs treated with postoperative radiotherapy following intentional marginal excision of soft tissue sarcomas from their limbs and to assess parameters for prognostic significance. Method: Patients that had had intentional marginal excision of limb soft tissue sarcomas followed by radiotherapy were selected. A coarse fractionated protocol of four once weekly 8 to 9 Gy by 4 MV x-rays was used. The time to local recurrence was determined. Tumour grade, size, site, number of surgeries, surgeon and time from last surgery to radiotherapy were evaluated as potential prognostic indicators. Results: Fifty-six cases were included. Minor surgical complications occurred in four patients (7%). Tumour recurred locally in 10 dogs (18%). Fourteen dogs died from tumour-related causes (25%). From Cox proportional hazard analysis time from surgery to radiotherapy was the only predictor of tumour recurrence (P=0·039); hazard ratio 8·63. Delaying radiotherapy beyond 4 weeks was associated with improved outcomes. Three dogs developed serious but non-life-threatening local complications; wound dehiscence, self-trauma and osteonecrosis of underlying bone. Clinical Significance: Intentional marginal excision followed by hypofractionated radiotherapy is a viable option for canine limb soft tissue sarcomas, providing good long-term clinical outcomes and low morbidity.     

Outcome following surgical removal of nonvisceral soft tissue sarcomas in cats: 42 cases (1992-2000)

OBJECTIVE: To identify factors associated with outcome of cats with nonvisceral soft tissue sarcomas treated with surgery alone. DESIGN: Retrospective study. ANIMALS: 42 cats. PROCEDURE: Medical records were reviewed for clinically relevant data, and histologic samples were examined. Follow-up information was obtained by means of physical examination or through telephone conversations with referring veterinarians and owners. The Kaplan-Meier method was used to construct survival curves. RESULTS: Median survival time was 608 days (range, 85 to 2,291 days), although 24 cats were still alive at the time of the study. Tumor size (ie, diameter) and histologic type were significantly associated with survival time. Median survival time was significantly longer in cats with tumors that were < 2 cm in diameter, compared with cats in which tumors were > 2 cm. Median survival times for cats with a fibrosarcoma or nerve sheath tumor were significantly longer than median time for cats with a malignant fibrous histiocytoma. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that tumor size and type are significantly associated with survival time in cats with nonvisceral soft tissue tumors.     

Factors influencing complete tumor excision of mast cell tumors and soft tissue sarcomas: a retrospective study in 100 dogs

The recommended treatment for soft tissue sarcomas (STS) and mast cell tumors (MCT) is complete surgical removal, provided that the tumor is amenable to surgical excision. The objective of this study was to evaluate possible risk factors for incomplete surgical excision of skin and subcutaneous STS and MCT in 100 dogs treated with wide excision with curative intent. Decreased body weight was a risk factor (P = 0.03, odd's ratio = 0.96) as well as increased tumor size (1.4% increase in risk of incomplete excision per cm(2); P = 0.02). Gender, age, breed, location, grade, tumor type, re-excision, and level of surgeon's training (P = 0.0711) were not significant. Veterinary surgery residents were at increased risk of incompleteness of excision compared with ACVS surgeons and ACVS surgeons with additional training in surgical oncology.