Radiological assessment of severity of canine nasal tumours and relationship with survival

A radiological assessment of 35 canine nasal tumours using an objective scoring system was carried out and related to patient survival. The scoring system demonstrated significant increases in disease-free interval and survival for dogs with scores of less than 12 compared to those with scores of 1 2 or above.     

Treatment of nasal tumours in dogs: a review

Nasal tumours are common neoplasms in dogs and often represent a diagnostic and therapeutic challenge due to their confined location within the nasal cavities. The main goal of this review is to extract the most relevant information from a wide and often confusing evidence-based medicine on the treatment of canine nasal tumours and conclude with current recommendations. This report highlights the different therapeutic modalities available and describes their technical aspects, interests and limitations. Megavoltage radiotherapy, as the most recent treatment and standard of care, is particularly examined, especially the different types of radiotherapy units, the main protocols used and their advantages and limits. Newer and non-conventional treatments are also discussed.     

Impact of primary tumour stage on survival in dogs with solitary lung tumours

Objectives: The objective of this study was to determine simple prognostic criteria for differentiation of canine solitary lung tumour cases into those that will and will not benefit from thoracic surgery. Methods: This was a retrospective study using the records of cases presented to Davies Veterinary Specialists, Hitchin, UK, from December 1998 to December 2005. Survival analyses were performed using the Kaplan-Meier and logrank methods. Potentially significant variables were evaluated by multivariate Cox analysis. Results: Forty-two patients met the inclusion criteria. Primary tumour stage T1, absence of neoplastic lymph nodes and metastases, and papillary tumour type were statistically significant favourable prognostic indicators on univariate analysis. Multivariate analysis attributed significance to primary tumour stage T1 and papillary type only. Median survival times were 555 days for T1N0M0 tumours of papillary type and 72 days for the remainder. Clinical Significance: Survival time following surgery in dogs with primary lung tumours was poor except in clinical stage T1N0M0 cases. These data support use of clinical techniques to dichotomise cases as T1N0M0 or other, improving decision making in thoracic surgery. These data validate initiation of prospective studies examining the role of chemotherapy in the management of advanced cases.     

Effects of stage and number of tumours on prognosis of dogs with cutaneous mast cell tumours

Between 1997 and 1999, 280 dogs with mast cell tumours were identified, of which 59 (21 per cent) had multiple tumours. Follow-up data for survival analysis were available for 145 dogs with single tumours and 50 dogs with multiple tumours. There was no significant difference between the survival times of the two groups; the survival rates after 12 and 24 months were 88 per cent and 83 per cent, respectively, for the dogs with single tumours, and 86 per cent at both intervals for the dogs with multiple tumours. Eight of the dogs with single tumours had lymph node metastases (stage II disease) and these dogs had a median survival time of 431 days, whereas the 50 dogs with multiple tumours (classified as stage III disease) and the dogs with single tumours (classified as stage I disease) had not reached their median survival times. Golden retrievers appeared to be predisposed to developing multiple tumours in the population studied, with an odds ratio of 3.8. This study found no evidence that dogs with multiple tumours had different survival times than those with single tumours, although there was evidence that the presence of lymph node metastasis generally carried a poorer prognosis.     

Long-term outcome of eight cats with non-lymphoproliferative nasal tumours treated by megavoltage radiotherapy

A retrospective study was undertaken to evaluate the long term survival of eight cats with non-lymphoproliferative nasal tumours treated by megavoltage radiotherapy alone. Adenocarcinoma was the most commonly diagnosed tumour. Megavoltage radiotherapy was given to eight cats in 4-6 fractions of 4-8 Gys over a 16 to 28 day period. Seven cats completed the radiotherapy schedule and only two cases developed mild acute radiotherapy side effects. Median survival time after the completion of the radiotherapy course as calculated by Kaplan-Meier survival analysis was 382 days. The 1 year survival rate was 63%. All cats were euthanased because of either a poor response to radiotherapy or recurrence of the nasal tumour. This study demonstrates that a coarse fractionation regime of megavoltage radiotherapy can provide effective long-term palliative treatment for feline nasal tumours. The coarse fractionation schedule has the advantages of requiring only four to six treatments.     

Outcome of accelerated radiotherapy alone or accelerated radiotherapy followed by exenteration of the nasal cavity in dogs with intranasal neoplasia: 53 cases (1990-2002)

OBJECTIVE: To compare long-term results of radiotherapy alone versus radiotherapy followed by exenteration of the nasal cavity in dogs with malignant intranasal neoplasia. DESIGN: Retrospective study. ANIMALS: 53 dogs with malignant intranasal neoplasia. PROCEDURE: All dogs underwent radiotherapy consisting of administration of 10 fractions of 4.2 Gy each on consecutive weekdays. For dogs in the surgery group (n=13), follow-up computed tomography was performed, and dogs were scheduled for surgery if persistent or recurrent tumor was seen. RESULTS: Perioperative complications for dogs that underwent surgery included hemorrhage requiring transfusion (2 dogs) and subcutaneous emphysema (8). Rhinitis and osteomyelitis-osteonecrosis occurred significantly more frequently in dogs in the radiotherapy and surgery group (9 and 4 dogs, respectively) than in dogs in the radiotherapy-only group (4 and 3 dogs, respectively). Two- and 3-year survival rates were 44% and 24%, respectively, for dogs in the radiotherapy group and 69% and 58%, respectively, for dogs in the surgery group. Overall median survival time for dogs in the radiotherapy and surgery group (477 months) was significantly longer than time for dogs in the radiotherapy-only group (19.7 months). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that exenteration of the nasal cavity significantly prolongs survival time in dogs with intranasal neoplasia that have undergone radiotherapy. Exenteration after radiotherapy may increase the risk of chronic complications.     

Stereotactic radiotherapy outcomes for intraventricular brain tumours in 11 dogs

Published radiotherapy data for canine intraventricular tumours are limited. In this retrospective, longitudinal study (9/2011–2018), 11 dogs with intraventricular masses were treated with stereotactic radiotherapy (SRT). Pathologic diagnosis was available from surgery or necropsy in 6/11 cases, revealing choroid plexus papilloma (3) or carcinoma (2), and ependymoma (1). The remainder were magnetic resonance imaging (MRI)-diagnosed as suspected choroid tumours or ependymomas. Tumours were located in the third or lateral ventricle (8), fourth ventricle (2), and cerebellopontine angle (1). Surgery was performed in three dogs prior to radiotherapy, and all showed gross residual/recurrent disease at treatment. Dogs received 8 Gray × 3 fractions (7), or 15 Gray × 1 fraction (4). Ten dogs were deceased at analysis, and one was living. The estimated median overall survival time (OS) from first SRT treatment was 16.9 months (515 days, 95% CI 33–1593 days). The survival time for two pathology-diagnosed carcinoma dogs were 24 and 133 days, respectively, and survival time for dogs with moderate to marked ventriculomegaly (4/11) ranged from 24 to 113 days. A total of 10/11 showed clinical improvement per owner or clinician, but two had short-lived benefits and were euthanized within 6 weeks of SRT. Limited conclusions on radiation-specific complications are possible due to the small dataset and limited follow-up imaging. This study provides preliminary evidence that radiotherapy outcomes are variable with intraventricular tumours, and some long-term survivors are noted.     

Recurrence rates and clinical outcome for dogs with grade II mast cell tumours with a low AgNOR count and Ki67 index treated with surgery alone

Grade II mast cell tumours (MCT) are tumours with variable biologic behaviour. Multiple factors have been associated with outcome, including proliferation markers. The purpose of this study was to determine if extent of surgical excision affects recurrence rate in dogs with grade II MCT with low proliferation activity, determined by Ki67 and argyrophilic nucleolar organising regions (AgNOR). Eighty‐six dogs with cutaneous MCT were evaluated. All dogs had surgical excision of their MCT with a low Ki67 index and combined AgNORxKi67 (Ag67) values. Twenty‐three (27%) dogs developed local or distant recurrence during the median follow‐up time. Of these dogs, six (7%) had local recurrence, one had complete and five had incomplete histologic margins. This difference in recurrence rates between dogs with complete and incomplete histologic margins was not significant. On the basis of this study, ancillary therapy may not be necessary for patients with incompletely excised grade II MCT with low proliferation activity.     

Treatment of eight dogs with nasal tumours with alternating doses of doxorubicin and carboplatin in conjunction with oral piroxicam

OBJECTIVE: To determine the efficacy and toxicity of chemotherapy in the treatment of canine nasal tumours. DESIGN: Retrospective clinical study PROCEDURE: Eight dogs with histologically confirmed nasal tumours were staged by means of complete blood count, serum biochemical analysis, cytological analysis of fine needle aspirate of the regional lymph nodes, thoracic radiographs and computed tomography scan of the nasal cavity. All dogs were treated with alternating doses of doxorubicin, carboplatin and oral piroxicam. All dogs were monitored for side effects of chemotherapy and evaluated for response to treatment by computed tomography scan of the nasal cavity after the first four treatments. RESULTS: Complete remission was achieved in four dogs, partial remission occurred in two dogs and two had stable disease on the basis of computed tomography evaluation. There was resolution of clinical signs after one to two doses of chemotherapy in all dogs. CONCLUSIONS: This chemotherapy protocol was efficacious and well tolerated in this series of eight cases of canine nasal tumours.     

Cytological lymph node evaluation in dogs with mast cell tumours: association with grade and survival*

The purpose of this retrospective cohort study is to describe the association of cytological assessment of lymph node metastasis with survival and tumour grade in dogs with mast cell tumours. Regional lymph node aspirates of 152 dogs diagnosed with a mast cell tumour were reviewed and classified according to specific cytological criteria for staging. 97 dogs (63.8%) had stage I tumours, and 55 (36.2%) had stage II tumours. Stage II dogs had a significantly shorter survival time than dogs with stage I disease (0.8 and 6.2 years, respectively; P < 0.0001). Dogs with grade III mast cell tumours were more likely to have stage II disease (P = 0.004). These results suggest that cytological evaluation of lymph nodes in dogs with mast cell tumours provides useful and valuable clinical information, and the results correlate with tumour grade and outcome thus providing a practical and non‐invasive method for staging.     

Long-term outcome of 56 dogs with nasal tumours treated with four doses of radiation at intervals of seven days

A retrospective study was undertaken on 56 dogs treated for nasal tumours by megavoltage radiotherapy with a hypofractionated schedule consisting of four doses of 9 Gy given at intervals of seven days. The dogs were followed until they died or were euthanased. The clinical signs had improved in 53 of the 56 dogs by the end of the treatment schedule. Mild acute radiation side effects were observed in the majority of the dogs but late radiation side effects were rare. Kaplan-Meier survival analysis revealed a median survival time after the final dose of radiation of 212 days. The one- and two-year survival rates were 45 per cent and 15 per cent. Fifty of the dogs were euthanased because the initial clinical signs recurred.     

Effects of xylazole alone and in combination with ketamine on the metabolic and neurohumoral responses in healthy dogs

ObjectiveTo evaluate the effects of xylazole (an analogue of xylazine), also known as Jingsongling, alone and in combination with ketamine, on metabolic and neurohumoral responses in healthy dogs.Study designProspective randomized experimental study.AnimalsTwelve healthy mongrel dogs (7 male, 5 female, aged 13–20 months, weighing 12.8–15.4 kg).MethodsEach dog received one of two treatments: xylazole 4 mg kg^?1 (group X n = 6); or xylazole 4 mg kg^?1 plus ketamine 10 mg kg^?1 (group XK; n = 6) intramuscularly. Pulse rate (PR), mean arterial pressure (MAP), respiratory rate (f_R), and rectal temperature (RT) were recorded before and from 5 to 100 minutes after drug administration. Venous blood samples were taken before and at intervals from 0.5 to 24 hours after drug administration for determination of plasma concentrations of norepinephrine, epinephrine, β–endorphin, cortisol, insulin, and glucose. Statistical analyses employed anova for repeated measures for changes with time and anova for comparison between treatments.ResultsIn both treatment groups. PR, f_R and RT decreased. MAP increased transiently. At some time points PR, MAP and RT were significantly lower in group X than group XK. Plasma norepinephrine, epinephrine, and insulin concentrations decreased, and β–endorphin and glucose concentrations increased with both treatments. Higher values of plasma norepinephrine, epinephrine, β–endorphin, and glucose concentrations were observed in the XK group compared with the X group.Conclusions and clinical relevanceThis study demonstrates that xylazole administered alone or in combination with ketamine in healthy dogs results in physiological, metabolic and neurohumoral responses similar to those seen after xylazine. Compared with xylazole alone, the combination of xylazole and ketamine reduced some of the responses.     

Effects of dexmedetomidine alone or in combination with opioids on intraocular pressure in healthy Beagle dogs

ObjectiveTo evaluate the effects of dexmedetomidine alone or in combination with different opioids on intraocular pressure (IOP) in dogs.Study designExperimental, prospective, crossover, randomized, blinded study.AnimalsA total of six Beagle dogs (two males and four females) aged 2 years and weighing 15.9 ± 2.9 kg (mean ± standard deviation).MethodsDogs were distributed randomly into seven treatments (n = 6 per treatment) and were administered dexmedetomidine alone (10 μg kg^–1; Dex) or in combination with butorphanol (0.15 mg kg^–1; DexBut), meperidine (5 mg kg^–1; DexMep), methadone (0.5 mg kg^–1; DexMet), morphine (0.5 mg kg^–1; DexMor), nalbuphine (0.5 mg kg^–1; DexNal) or tramadol (5 mg kg^–1; DexTra). All drugs were administered intramuscularly. IOP was measured before drug injection (time 0, baseline) and every 15 minutes thereafter for 120 minutes (T15–T120).ResultsThere were significant reductions in IOP compared with baseline in treatments Dex and DexMep at times T30–T120, and in treatment DexMet at T15–T90. IOP decreased compared with baseline in treatments DexBut, DexNal and DexTra at all evaluation times. No changes in IOP were seen in treatment DexMor. The mean IOP values in treatment DexMet at T105–T120 were higher than those for other treatments.Conclusions and clinical relevanceDexmedetomidine alone or in combination with butorphanol, meperidine, methadone, nalbuphine or tramadol resulted in decreased IOP for 120 minutes in dogs. The magnitude of the reduction was small and lacked clinical significance.     

Prognostic significance of specific magnetic resonance imaging features in canine nasal tumours treated by radiotherapy

Objectives : To investigate the prognostic significance of the magnetic resonance (MR) findings of meningeal hyperintensity of the olfactory bulbs and tumour extension into the caudal nasal recess (CNR) in dogs with nasal tumours treated by radiotherapy. Methods : MR images of 41 dogs with nasal tumours treated with radiotherapy were reviewed. The occurrence of neurological signs and survival of patients with and without meningeal hyperintensity of the olfactory bulbs and tumour extension into the CNR were analysed together with possible confounding factors including intracranial extension and patient age. Results : There was no significant association between the presence of meningeal hyperintensity or CNR involvement and the occurrence of neurological signs. Although there was a tendency towards shorter survival in dogs with tumour extension into the CNR, multivariable analysis showed no significant difference in survival between dogs with/without CNR involvement, meningeal hyperintensity or intracranial tumour extension (P=0·12, 0·50 and 0·57, respectively). Clinical Significance : In dogs with nasal tumours treated with radiotherapy, tumour extension into the cranium is not necessarily associated with shorter survival in patients without neurological signs at time of diagnosis. Although a definite influence of CNR involvement on case outcome could not be demonstrated, studies with a larger population are warranted.     

Treatment of canine mast cell tumours with prednisolone and radiotherapy

This retrospective study describes 35 dogs with non‐resectable, grade I–III mast cell tumours on the head or limb treated with prednisolone (40 mg m^?2 daily) for 10–14 days prior to radiotherapy (4 × 800 cGy fractions at 7‐day intervals) from a 4 MV linear accelerator. Prednisolone was continued at a reduced dose rate (20 mg m^?2) during radiotherapy and for 2 months or longer afterwards. Eighteen of 24 tumours (75%) decreased in size in response to prednisolone treatment. By 6–8 weeks following radiotherapy, 12 dogs had achieved a complete remission and 19 a partial response. Two tumours remained static and two progressed during the course of treatment. The overall response rate was 88.5%. With long‐term follow‐up, 11 dogs experienced local recurrence (n = 4), metastasis (n = 5) or both (n = 2). The median progression‐free interval was 1031 days (95% CI 277.44–1784.56, Kaplan–Meier), with 1‐ and 2‐year progression‐free rates of 60 and 52%, respectively. Tumour grade did not predict the prognosis for this group of dogs, but tumour location did affect the outcome. Dogs with tumours located on the limb survived longer than those with tumours on the head. The combination of prednisolone with radiotherapy appears to have a useful role in the management of measurable mast cell tumours sited on the head and distal extremities.