A retrospective study of chemotherapeutic effect without wide-margin surgery or radiation therapy in dogs with oral malignant melanoma.

Background: Effective treatment for canine oral malignant melanoma (e.g., curative-intent surgery) may not be feasible or radiation therapy may be unavailable. However, chemotherapy is usually an option, and more information is needed regarding its use without adequate local treatments. Objective: Our objective was to investigate the efficacy of chemotherapy in canine oral malignant melanoma without adequate local control, using carboplatin with dose reduction in small-breed dogs and metronomic chemotherapy. Animals and procedure: Client-owned dogs with histopathologically diagnosed oral malignant melanoma were retrospectively enrolled from 2016 to 2022. The chemotherapy protocol in each case was determined by the attending clinician. Results: Thirteen dogs were included. The median progression-free interval of all 13 dogs was 42 d (14 to 953 d). The median overall survival time of dogs with chemotherapy as their only systemic treatment was 181 d (50 to 960 d; n = 11). The median dosage of carboplatin was 250 mg/m2. Response to treatment and clinical stage were significant prognostic factors. Conclusion and clinical relevance: As chemotherapy provided a median survival of 6 mo, it could be considered when adequate local control is infeasible. Earlier clinical stages or achievement of at least stable disease during chemotherapy may indicate better survival in dogs.

Une étude rétrospective de l'effet chimiothérapeutique sur le mélanome malin buccal canin dépourvu de chirurgie et de radiothérapie á large marge : le stade clinique et la réponse au traitement prédisent les résultats du patient. Mise en contexte: Des traitements efficaces pour le mélanome malin oral canin, tels que la chirurgie á visée curative, ne sont parfois pas réalisables ou la radiothérapie n'est pas disponible dans certaines régions. La chimiothérapie reste une option de traitement et davantage d'informations devraient être fournies pour les cas qui n'ont pas eu accés á un traitement local adéquat. Objectif: Cette étude visait á étudier l'efficacité de la chimiothérapie dans le mélanome malin oral canin sans contrôle local adéquat, en utilisant le carboplatine avec réduction de dose chez les chiens de petite race et la chimiothérapie métronomique. Animaux et procédure: Treize chiens appartenant á des clients atteints d'un mélanome malin oral diagnostiqué par histopathologie ont été rétrospectivement inscrits de 2016 á 2022. Le protocole de chimiothérapie a été déterminé par le clinicien traitant. Résultats: L'intervalle médian sans progression des treize chiens était de 42 jours (14­953 jours). La durée médiane de survie globale des chiens ayant reçu une chimiothérapie comme seul traitement systémique était de 181 jours (50­960 jours; n = 11). La dose médiane de carboplatine était de 250 mg/m2. La réponse au traitement et le stade clinique étaient des facteurs pronostiques importants. Conclusion et pertinence clinique: La chimiothérapie pouvait encore être envisagée lorsqu'un contrôle local adéquat était impossible. Des stades cliniques plus précoces ou des patients atteignant au moins une maladie stable pendant la chimiothérapie peuvent indiquer une meilleure survie.(Traduit par les auteurs).

Reason for euthanasia in dogs with urothelial carcinoma treated with chemotherapy or radiation therapy or both: A retrospective observational study.

BACKGROUND: Clients want to know the ultimate cause of death in their pet after cancer treatment. The cause of euthanasia and investigation of urinary obstruction in treated dogs with urothelial carcinoma (UC) has not been specifically reported in veterinary literature. HYPOTHESIS/OBJECTIVES: Our hypothesis was that the majority of treated dogs with UC are euthanized secondary to primary tumor factors, such as urinary obstruction. ANIMALS: Fifty-nine client-owned dogs diagnosed with UC. METHODS: Retrospective observational study on clinical signs and disease at euthanasia of dogs with UC treated by radiation therapy or chemotherapy or both. RESULTS: The median overall survival time (OST) of all dogs was 339 days (range, 17-1996; 95% confidence interval [CI], 185-392; interquartile range [IQR], 112-505). Of dogs deemed to have been euthanized because of UC (50/59, 85%), the primary cause was considered to be local progression in 31/50 (62%), most often because of perceived complete or partial urinary obstruction (24/31, 77%). No variables were found to be predictive of urinary obstruction. The overall documented metastatic rate was 56%. In dogs euthanized because of UC, metastasis was deemed to be the cause in 19/50 (38%) dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Regardless of the type of treatment, UC in dogs has a poor prognosis and there is a continuing need to improve treatments that focus on local control of the primary tumor, given its high contribution to the decision for euthanasia. Proactive management to avoid the high frequency of urinary obstruction may be worthy of future investigation.

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.

Outcomes of 35 dogs with craniomaxillofacial osteosarcoma treated with stereotactic body radiation therapy.

Canine craniomaxillofacial osteosarcoma (OSA) is most commonly treated surgically; however, in cases where surgery is not feasible or non-invasive treatment is desired, stereotactic body radiation therapy (SBRT) may be elected for local tumour control. In this study, we evaluated 35 dogs treated with SBRT. Nine dogs (26%) had calvarial, seven (20%) had mandibular and 19 (54%) had maxillary OSA. Median time to first event (TFE) was 171 days, and overall median survival time (MST) was 232 days. Site-specific MSTs were 144 days for mandible, 236 days for calvarium and 232 days for maxilla (p = .49). Pulmonary metastatic disease was observed in 12/35 (34%) patients and was detected pre-SBRT in six dogs (17%) and post-SBRT in the remaining six dogs (17%). Eighteen adverse events post-SBRT were documented. Per veterinary radiation therapy oncology group criteria, five were acute (14%) and three were late (9%) grade 3 events. Neurological signs in two dogs were suspected to be early-delayed effects. Cause of death was local progression for 22/35 (63%) patients, metastasis for 9/35 (26%) patients and unknown for four. On univariate analysis, administration of chemotherapy was associated with a longer TFE (p = .0163), whereas volume of gross tumour volume was associated with a shorter TFE (p = .023). Administration of chemotherapy and five fractions versus single fraction of SBRT was associated with increased survival time (p = .0021 and .049). Based on these findings, a treatment protocol incorporating chemotherapy and five fractions of SBRT could be considered for dogs with craniomaxillofacial OSA electing SBRT with careful consideration of normal tissues in the field.

Periodontal Pocket Therapy Using a Class IV Dental Diode Laser in Dogs: A Retrospective Analysis.

Class IV dental diode lasers have been introduced as a nonsurgical therapy for periodontal pockets in veterinary and human dentistry. This retrospective case series evaluates the use of Class IV dental diode laser therapy for abnormal periodontal pockets in a specialty veterinary dental practice. A hypothesis that the Class IV diode dental laser is a useful adjuvant modality in canine periodontal pocket therapy in the reduction of clinical pocket depth was made. This article discusses and demonstrates diode laser use in periodontal pocket therapy in a specialty veterinary dental practice and reviews the current literature. Inclusion in this study was limited to client-owned dogs with noted periodontal pocketing on any tooth type between 3 and 6 mm, which were treated with closed root planing (RP/C) and laser therapy who returned in 6 to 7 months for recheck of the pockets from the years 2017 to 2020. Twelve patients met the inclusion criteria. A total of 128 periodontal pockets were included in the study. Each periodontal pocket was a case receiving therapy. The mean periodontal pocket depth before the treatment is measured as 3.35 mm. The mean pocket depth of the periodontal pockets following treatment was 0.59 mm. The mean improvement in periodontal pocket depths after diode laser therapy when considering patient and tooth number using linear mixed-effects modeling was 2.63 mm (95% confidence interval [CI]: 1.81-3.46, P < .0001). No statistically significant results were observed for pocket type, as P values were greater than .05.

Photobiomodulation therapy in dogs undergoing TPLO after cranial cruciate ligament rupture shows promise but no statistically significant difference in a randomized trial.

OBJECTIVE: Effect of photobiomodulation therapy (PBMT) in patients with CCLR after TPLO surgery by measuring C-reactive protein (CRP), percentage weight bearing, lameness using a short form of a composite measure pain scale, evaluated by the clinician and owners, and surgical site infection. SAMPLE: 54 client-owned dogs with CCLR undergoing unilateral TPLO surgery were enrolled in this study between April 5, 2021, through April 10, 2022. METHODS: The study population was randomly assigned to either a treatment group receiving PMBT (24 dogs) or a control group (30 dogs). PMBT was performed on the treatment group immediately after induction, and 6 hours, 24 hours, 48 hours, and 8 weeks postoperatively. The control group received sham PMBT (device turned off) at the same time. Evaluation of CRP, CMPS-SF, evidence of SSI, and %WB were evaluated for all dogs 24 hours preoperatively, and then 24 hours, 48 hours, and 8 weeks postoperatively. Owners completed CMPS-SF and subjective evaluations weekly for 8 weeks postoperatively. RESULTS: No statistically significant differences were found between treatment groups when evaluating CRP, %WB, and CMPS-SF by the clinician and weekly evaluation of the CMPS-SF by owners. Although no statistically significant differences were found in patients developing surgical site infections between treatment groups, SSI was only observed in patients in the control group (5/30, 16.6%). Most were minor/superficial infections (4/30 13.3%), and a single dog (1/30, 3.3%) had a major/deep surgical site infection. CLINICAL RELEVANCE: Although with promising but not statistically significant differences between groups, surgical site infections may be reduced after PBMT application.

Impact of palliative-intent radiotherapy with or without chemotherapy on lameness in flat coat retrievers with localised periarticular histiocytic sarcoma - a retrospective cohort, single institution study.

Histiocytic sarcoma (HS) is a common tumour in flat coat retrievers (FCRs) often affecting periarticular tissues and joints. Palliative-intent radiotherapy, seeks to achieve local tumour control, pain relief and improve limb function. However, the effect of palliative-intent radiotherapy on analgesic levels of dogs with localised HS has not been studied. We hypothesised that palliative-intent radiotherapy could improve lameness in dogs affected by localised HS. This study aimed to assess the impact of palliative-intent radiotherapy on lameness of FCRs with localised HS. A retrospective cohort single institution study was performed. Medical records of FCR dogs with HS that received external beam radiotherapy between 2003 and 2022 were reviewed and included demographic, staging, severity of baseline lameness, therapeutic management and outcome data. Descriptive statistics, McNemar's chi-squared test, Fisher's exact test and Kaplan-Meier analysis were used for statistical analysis. Thirty-nine dogs were included with a median age of 7.2 years, 25 were male and 14 were female. HS was most commonly located in the forelimb (29 dogs, 74.3%), affecting the shoulder joint (19 dogs, 48.7%). Staging was performed in all 39 dogs with 22 (56.4%) dogs having localised HS, six (15.3%) dogs had localised HS with node metastasis and 11 (28.2%) dogs had localised HS with systemic metastasis. All dogs received palliative-intent hypo-fractionated radiation therapy, 32 (82%) dogs showed improvement in lameness. In conclusion, palliative intent radiation treatment has an analgesic effect reducing lameness or clinical signs associated with affected tumour-bearing joints.

Stereotactic radiotherapy for advanced canine anal sac adenocarcinoma: an exploratory study.

For dogs with anal sac adenocarcinoma (ASAC), metastasis to intra-abdominal and pelvic lymph nodes occurs early in the disease course. Death is usually related to locoregional progression. Surgical excision is the treatment of choice, but may not be possible in advanced cases. Dogs treated with RT in the gross disease setting showed a 38%-75% overall response rate, but side effects to organs at risk in this area (especially the colon, bladder, and spinal cord) were reported. Stereotactic radiation therapy (SRT) utilizes highly conformal treatment planning with rapid dose fall-off and hypofractionation. SRT may help to reduce the risk of late side effects of radiation while also creating a larger biological effect on ASACs. A primary aim of this prospective, descriptive, exploratory study was to describe the safety and feasibility of an SRT protocol in a small sample of dogs with ASAC, using objective and subjective measures to monitor acute and late side effects. A secondary aim was to describe the anti-tumor response of the SRT protocol using CT at 3- and 6 months posttreatment. Five dogs completed the radiation protocol. Four had follow-up CT characteristics of complete response (1), partial response (2), and stable disease (1). Minimal acute side effects were observed. Despite some large tumor volumes, constraints for OAR were achieved in all but the spinal cord for one patient. Findings indicated that SRT is a safe and feasible treatment for dogs with ACAC. Future studies are warranted to compare patient outcomes for SRT versus other treatments.

Radiotherapy in combination with exenteration and partial orbitectomy for orbital multilobular tumor of bone in a Cocker Spaniel.

Background: Multilobular tumor of bone or multilobular osteochondrosarcoma is a tumor of flat bone in the skull. The treatment of choice for a multilobular tumor of bone is local aggressive surgical excision. Case Description: A female Cocker Spaniel dog aged 11 years presented with a history of globe displacement of the right eye for 3 months. Ophthalmic examination revealed exophthalmos, third eyelid protrusion, and slightly increased intraocular pressure OD (oculus dexter; right eye). Computed tomography (CT) revealed a mass effect in the right retrobulbar, maxilla, zygomatic, and temporal areas. Right zygomatic and temporal bone lysis were observed. Physical examination, hematology, and blood chemistry results were within normal limits. Exenteration with zygomatic arch removal was performed. During surgery, a firm 2-lobed mass (4.8 × 3.7 and 1.6 × 1.4 cm) adhered to the mandible was found in the retrobulbar area OD. Histopathological findings revealed a multilobular tumor of bone. CT imaging was performed for the remaining tumor and an extended part of the right retrobulbar mass was found. Hypofractioned radiotherapy with 6 fractions of 6 Gy was performed on days 0, 7, 14, 21, 28, and 35. At 1-month and 4-month follow-up inspections, the mass gradually reduced in size. At 8 months and 11 months after radiotherapy, the mass was unremarkable. The dog was alert during all follow-up periods to 1 year and 8 months after hypofractioned radiotherapy combined with exenteration and partial orbitectomy. Conclusion: Hypofractioned radiotherapy combined with exenteration and partial orbitectomy extended the patient's survival and decreased the size of the remaining tumor for the management of orbital multilobular tumor of bone in this dog for at least 1 year and 8 months.

Intensity-modulated radiotherapy and chemotherapy for canine right atrial tumors: A retrospective study of seven dogs.

Most primary cardiac tumors in dogs are located in the right atrium/atrial appendage, with hemangiosarcoma being the most common. The aims of this retrospective, case series were to describe outcomes for seven dogs with right atrial tumors treated with hypofractionated intensity-modulated radiotherapy and concurrent vinblastine and propranolol. One dog had a complete response, four dogs had partial responses and two dogs had stable disease after treatment. Effusions resolved in all dogs. Median progression-free survival was 290 days. Five dogs died from metastatic disease, one dog from unrelated neoplasia, and one dog is alive. Median overall survival was 326 days. Three dogs with confirmed hemangiosarcoma survived 244, 326, and 445 days. Two dogs developed clinically significant, but nonfatal, cardiac arrhythmias. One dog that received three courses of radiation had subclinical myocardial and arterial fibrosis at necropsy. Hypofractionated chemoradiotherapy was well tolerated and may provide clinical benefit in dogs with right atrial tumors.

Long-term remission and survival in dogs with high-grade, B cell lymphoma treated with chemotherapy with or without sequential low-dose rate half-body irradiation.

BACKGROUND: Standard of care for dogs with high-grade lymphoma, multiagent chemotherapy, achieves good initial responses but long-term remissions are infrequent; previous studies using half-body irradiation suggest improved long-term outcomes. HYPOTHESIS: The addition of low-dose rate half-body irradiation would improve outcomes in dogs with B-cell lymphoma. ANIMALS: Client-owned dogs with stage III or higher, substage a, B-cell lymphoma that achieved complete remission after 4 doses of multiagent chemotherapy. METHODS: A case-controlled design comparing 2-year remission and survival rates between dogs treated with CHOP-based chemotherapy and those treated with chemotherapy and sequential low-dose rate half-body irradiation. RESULTS: Thirty-eight dogs were enrolled with 18 included in final analysis, 9 prospectively-enrolled dogs and 9 case-matched historical controls. The irradiation cohort's 2-year disease-free rate was 56% whereas median duration exceeded the 730-day study period compared with 0% and 261 days in the chemotherapy only group. Remission duration significantly differed between cohorts (P < .01), hazard ratio 0.218 (95% CI: 0.06-0.77). The irradiation cohort's 2-year survival rate was 78% with median overall survival duration exceeding the 730 day study period compared with 11% and 286 days in the chemotherapy only group. Overall survival time significantly differed between cohorts (P < .02), hazard ratio 0.173 (95% CI: 0.03-0.839). CONCLUSIONS AND CLINICAL IMPORTANCE: The improved long-term outcome achieved by dogs administered sequential low-dose rate half-body irradiation in this study is similar to previous observational studies. Where long-term remission is sought in dogs with B-cell lymphoma low-dose rate half-body irradiation could be considered in addition to standard chemotherapy.

Extracellular heat shock protein 70 levels in tumour-bearing dogs and cats treated with radiation therapy and hyperthermia.

Hyperthermia is a form of a cancer treatment which is frequently applied in combination with radiotherapy (RT) to improve therapy responses and radiosensitivity. The mode of action of hyperthermia is multifactorial; the one hand by altering the amount of the blood circulation in the treated tissue, on the other hand by modulating molecular pathways involved in cell survival processes and immunogenic interactions. One of the most dominant proteins induced by hyperthermia is the major stress-inducible heat shock protein 70 (Hsp70). Hsp70 can be found in the blood either as a free-protein (free HSP70) derived from necrotic cells, or lipid-bound (liposomal Hsp70) when it is actively released in extracellular vesicles (EVs) by living cells. The aim of the study was to evaluate the levels of free and liposomal Hsp70 before and after treatment with RT alone or hyperthermia combined with radiotherapy (HTRT) in dogs and cats to evaluate therapy responses. Peripheral blood was collected from feline and canine patients before and at 2, 4, 6 and 24 h after treatment with RT or HTRT. Hsp70 enzyme-linked immunosorbent assays (ELISAs) were performed to determine the free and liposomal Hsp70 concentrations in the serum. The levels were analysed after the first fraction of radiation to study immediate effects and after all applied fractions to study cumulative effects. The levels of free and liposomal Hsp70 levels in the circulation were not affected by the first singular treatment and cumulative effects of RT in cats however, after finalizing all treatment cycles with HTRT free and liposomal Hsp70 levels significantly increased. In dogs, HTRT, but not treatment with RT alone, significantly affected liposomal Hsp70 levels during the first fraction. Free Hsp70 levels were significantly increased after RT, but not HTRT, during the first fraction in dogs. In dogs, on the other hand, RT alone resulted in a significant increase in liposomal Hsp70, but HTRT did not significantly affect the liposomal Hsp70 when cumulative effects were analysed. Free Hsp70 was significantly induced in dogs after both, RT and HTRT when cumulative effects were analysed. RT and HTRT treatments differentially affect the levels of free and liposomal Hsp70 in dogs and cats. Both forms of Hsp70 could potentially be further investigated as potential liquid biopsy markers to study responses to RT and HTRT treatment in companion animals.

A retrospective study of sinonasal tumors in 182 dogs treated with stereotactic radiotherapy (3 × 10 Gy) (2010-2015).

BACKGROUND: Stereotactic radiotherapy (SRT) is an emerging treatment for sinonasal tumors in dogs. Reported results regarding tumor control and incidence of acute and late radiation morbidities are inconsistent. OBJECTIVES: To determine treatment efficacy and prognostic indicators of SRT in dogs with sinonasal tumors and to quantify acute and late radiation morbidities. ANIMALS: One hundred and eighty-two client-owned dogs with sinonasal tumors diagnosed cytologically, histologically, or radiographically that underwent SRT. METHODS: Single-arm retrospective study by reviewing medical records of dogs treated with SRT (10 Gy × 3) between 2010 and 2015. Kaplan-Meier analysis was used to determine overall survival (OST; from the first day of SRT to death by any cause) and disease-specific survival times (DSST; OST but censoring tumor/treatment-unrelated death). Tumors were staged using modified Adams criteria. RESULTS: Median OST and DSST of dogs treated with 1 course of SRT was 441 (95% CI: 389-493 days) and 482 (428-536 days) days, respectively with skin/oral cavity acute morbidities observed in 3% of dogs. DSST in dogs with stage 4 disease showed no statistical difference compared to other stages (P = .64). Oro-nasal (n = 2) or naso-cutaneous (n = 11) fistula development occurred in 7.1% of dogs with median time of 425 days (range: 83-1733 days). Possible chronic rhinitis after SRT was recorded in 54 of 88 dogs (61%) where information was available. CONCLUSIONS AND CLINICAL IMPORTANCE: Results are comparable to other reports of treatment of SRT. Acute morbidities were minimal. Modified Adams stage scheme appeared to be inappropriate for prognostication for dogs with sinonasal tumors treated with SRT.

Retrospective study evaluating the efficacy of stereotactic body radiation therapy for the treatment of confirmed or suspected primary pulmonary carcinomas in dogs.

Canine primary pulmonary carcinomas (PCCs) are commonly treated with surgery with overall median survival times (MST) around a year; however, due to extent of disease, prognosis, or client preference, alternative treatments have been considered. Stereotactic body radiation therapy (SBRT) has been utilized in human cancer patients for local control of lung tumours as a surgical alternative. Twenty-one PCCs in 19 dogs that received SBRT for local control were retrospectively evaluated. Dogs were staged according to the canine lung carcinoma stage classification (CLCSC) system with three as Stage 1, five as Stage 2, three as Stage 3, and eight as Stage 4. Overall MST was 343 days with 38% of patients alive at 1 year. Stage did not significantly impact survival time (p = .72). Five (26%) dogs had lymphadenopathy and MST was not significantly different from dogs without lymphadenopathy (343 vs. 353 days; p = .54). Five out of 18 evaluable dogs (28%) experienced acute lung VRTOG effects and 2 of 12 dogs (17%) experienced late lung VRTOG effects. Median lung dose, V5, V20, and D30 to the lung did not correlate significantly with the development of adverse radiation events. Twelve dogs had follow-up imaging and the best response included a complete response (17%), partial response (42%), and stable disease (42%). Progressive disease was noted in seven dogs a median of 229 days after SBRT. SBRT was documented to be a safe and effective alternative to surgery and may have survival advantages for Stage 3 or 4 dogs according to the CLCSC.

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.

Single high-dose radiation therapy and liquid fiducial markers can be used in dogs with incompletely resected soft tissue sarcomas.

OBJECTIVE: To evaluate the outcome and effects of single high-dose radiation therapy with the aid of liquid fiducial markers in dogs following resection of soft tissue sarcomas (STSs). ANIMALS: 36 client-owned dogs. METHODS: Dogs with a histologic diagnosis of a grade II or III STS that underwent liquid fiducial guided single fraction, 20-Gy stereotactic radiation therapy following surgical excision of an STS between May 2017 and March 2019 were prospectively enrolled in this study. Data collected from the medical records included patient signalment, tumor-related information, treatment details, and outcome. Kaplan-Meier survival analysis was performed for overall survival time (OST) and disease-free interval (DFI). The median OST and DFI were not reached, so restricted mean OST and DFI were also calculated. RESULTS: 36 dogs were included in the study. All dogs underwent radiation therapy a mean of 36.1 days (range, 20 to 59 days) after surgery. Acute and delayed radiation toxicity effects occurred in 80.5% and 36.1% of dogs, respectively, all of which affected the skin. Tumor recurrence was noted in 24.3% of dogs with a median time to recurrence of 272 days (range, 14 to 843 days). The restricted mean OST was 1,556 days (range, 1,383 to 1,728 days) and restricted mean DFI was 1,330 days (range, 1,101 to 1,559 days). CLINICAL RELEVANCE: The results of this study showed that administering a single 20-Gy fraction of radiation in combination with a liquid fiducial marker to treat marginally or incompletely resected STS in the absence of gross disease resulted in similar OST and DFI compared to other previously reported radiation protocols.

Use of CT and MR imaging in radiation therapy planning of imaging-diagnosed canine intracranial meningioma achieves better tumor coverage than CT alone.

The aim of this retrospective, secondary analysis study was to quantify the dosimetric impact of the lack of interobserver agreement on gross tumor volume (GTV) delineation for canine meningioma. This study used a previously reported population of 13 dogs with GTVs contoured on CT alone and on registered CT-MR by 18 radiation oncologists. The "true" GTV was generated for each dog using a simultaneous truth and performance-level estimation algorithm, and "true" brain was defined as the whole brain minus true GTV. Treatment plans were generated for each dog and observer combination, using criteria applied to the observer's GTV and brain contours. Plans were then categorized as a pass (met all planning criteria for true GTV and true brain) or fail. A mixed-effects linear regression was performed to examine differences in metrics between CT and CT-MR plans and mixed-effects logistic regression was performed to examine differences in percentages of pass/fail between CT and CT-MRI plans. The mean percent coverage of true GTV by prescribed dose was higher for CT-MR plans than for CT plans (mean difference 5.9%; 95% CI, 3.7-8.0; P < 0.001). There was no difference in the mean volume of true brain receiving ≥24 Gy and in maximum true brain dose between CT plans and CT-MR plans (P ≥ 0.198). CT-MR plans were significantly more likely to pass the criteria for true GTV and true brain than CT plans (OR 1.75; 95% CI, 1.02-3.01; P = 0.044). This study demonstrated significant dosimetric impact when GTV contouring was performed on CT alone compared with CT-MR.

Treatment of canine periocular dermatitis with rhytidectomy (surgical face-lift) and fluorescence photobiomodulation: A case report.

Canine periocular dermatitis may be associated with excessive facial folds and heavy brows (EFF-HB). There is no gold standard therapy for EFF-HB-associated periocular dermatitis, and conventional medical management may fail. Herein, we describe periocular fluorescence photobiomodulation and rhytidectomy as novel approaches to treat EFF-HB-associated periocular dermatitis refractory to medical management.

La dermatite périoculaire canine peut être associée à des plis faciaux prononcés et à des sourcils épais (EFF-HB). Il n'y a pas de traitement de référence de la dermatite périoculaire associée à l'EFF-HB, et la prise en charge médicale conventionnelle peut échouer. Ici, nous décrivons la photobiomodulation par fluorescence périoculaire et la rhytidectomie comme de nouvelles approches pour traiter la dermatite périoculaire associée à l'EFF-HB réfractaire à la prise en charge médicale.

La dermatitis periocular canina puede estar asociada con pliegues faciales excesivos y cejas densas (EFF-HB). No existe una terapia estándar para la dermatitis periocular asociada a EFF-HB, y el tratamiento médico convencional puede fallar. En este artículo describimos el uso de fotobiomodulación periocular de fluorescencia y ritidectomía como nuevas terapias para tratar la dermatitis periocular asociada a EFF-HB refractaria al tratamiento médico habitual.

A dermatite periocular canina pode estar associada a dobras faciais excessivas e sobrancelhas pesadas (EFF-HB). Não há nenhuma terapia de padrão ouro para dermatite periocular associada a EFF-HB, e os tratamentos clínicos convencionais podem falhar. Neste trabalho, nós descrevemos a fotobiomodulação fluorescente periocular e a retidectomia como novas abordagens para o tratamento de dermatite periocular associada a EFF-HB refratária ao tratamento medicamentoso.

Superficial kilovoltage x-ray radiotherapy for the treatment of cutaneous mast cell tumors on the head in three dogs and one cat: a limited retrospective case series.

OBJECTIVE: To report preliminary findings of hypofractionated superficial radiotherapy for treatment of cutaneous mast cell tumors (MCTs) and report the acute and late toxicity associated with its use. ANIMALS: 3 dogs and 1 cat. PROCEDURES: In this retrospective study, medical records from January 2021 through July 2022 were searched for animals that received superficial radiation therapy for MCTs of the head. RESULTS: 4 patients with 5 MCTs were included. Three of the masses were periocular and required protection of the globe with a tungsten eye shield. One patient did not complete the intended protocol due to diffuse metastatic spread noted after the second fraction. Of the 3 patients that completed their protocol, 100% had a complete response. Two canine patients were treated adjunctively with toceranib. Two of the 4 patients experienced grade 1 acute veterinary radiation therapy oncology group (VRTOG) toxicity, and the 3 patients that completed their protocol experienced grade 1 late VRTOG toxicity. No radiation effects were documented to the cornea or lens in any patient. CLINICAL RELEVANCE: Superficial radiation therapy was effective in our limited study population, and patients experienced minimal side effects for treatment of cutaneous MCTs.

Use of a colorimeter is a viable method to measure melanin and erythema content in the context of laser beam attenuation by use of a class IV laser in different tissues in dogs.

OBJECTIVE: Patient factors may alter laser photon attenuation, but these factors have not been adequately evaluated in live dogs. Our objective was to evaluate class IV laser beam attenuation (LBA) by canine tissues using a colorimeter to evaluate melanin and erythema indices. We hypothesized that greater melanin and erythema indices and unclipped hair would increase LBA, and these properties would vary among tissues. ANIMALS: 20 client-owned dogs. PROCEDURES: Between October 1 and December 1, 2017, colorimeter measurements and LBA in various tissues before and after clipping overlying hair were evaluated. Data were analyzed using generalized linear mixed models. Statistical significance was set at P < .05. RESULTS: LBA was greater in unclipped (98.6 ± 0.4%) than clipped hair (94.6 ± 0.4%). The least LBA occurred in the pinna (93%) while the greatest occurred in the caudal vertebra (100%) and caudal semitendinosis muscles (100%). Each mm of tissue thickness resulted in LBA of 11.6%. Each unit increase in melanin index resulted in a 3.3% increase in LBA. There was no association of LBA with erythema index. CLINICAL RELEVANCE: To our knowledge, this is the first study that evaluated LBA by different tissues in live dogs using a colorimeter to evaluate melanin and erythema indices. We recommend clipping hair prior to photobiomodulation to decrease laser beam attenuation and using increased laser doses in thicker tissues and dogs with high melanin content. The colorimeter may be helpful in customizing patient treatment dosimetry. Future studies are necessary to determine therapeutic laser doses for adequate photobiomodulation effects.