CHARACTERIZATION OF NORMAL TISSUE COMPLICATIONS IN 51 DOGS UNDERGOING DEFINITIVE PELVIC REGION IRRADIATION

Radiotherapy for Canine Apocrine Gland Anal Sac Adenocarcinoma: Survival Outcomes and Side Effects of a Palliative Treatment Protocol of 20 Gy in Five Consecutive Fractions

This research aims to evaluate the outcomes of a radiotherapy protocol, consisting of five fractions of 4 Gy each, resulting in a total dose of 20 Gy for apocrine gland anal sac tumors and local lymph nodes in canines. This protocol was assessed as a palliative treatment for macroscopic tumors alone, or in combination with additional therapies under different scenarios. Medical records from fifty canine patients met the inclusion criteria and were divided into different treatment groups: radiotherapy alone (n = 22, 44%), radiotherapy with chemotherapy or targeted therapy with toceranib (n = 18, 36%), surgery with radiotherapy (n = 5, 10%), and surgery with radiotherapy and chemotherapy or targeted therapy with toceranib (n = 5, 10%). Patients who received radiotherapy alone had a median survival time of 384 days (95% CI 198-569) and 628 days (95% CI 579-676) for RT + additional therapies. The median time to progression for patients with radiotherapy alone was 337 days (95% CI 282-391 days), and 402 days (95% CI 286-517 days) for radiotherapy plus additional treatments. Acute side effects were mild, with the majority having diarrhea (61%), and only one patient developed grade III late effects VRTOG v2 classification; however, this happened 22 months after the first radiotherapy protocol after re-irradiation. The results demonstrate that radiotherapy alone under this protocol provided a comparable median time to progression vs. radiotherapy plus additional treatments while maintaining acceptable side effects. The combination of this protocol with other treatment modalities offers attractive results for local disease control and survival while maintaining acceptable toxicities. Overall, these findings contribute to the growing evidence supporting the role of radiotherapy in managing apocrine gland anal sac adenocarcinoma in dogs.

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.

Palliative radiation therapy as a treatment for feline urinary bladder masses in four cats

CASE SERIES SUMMARY

Urinary bladder masses in four cats were treated with palliative radiation therapy (RT). Three cats were previously diagnosed with chronic kidney disease (CKD): International Renal Interest Society (IRIS) stage 2 in two cats and IRIS stage 3 in one cat. One cat had a diagnosis of hyperthyroidism and inflammatory bowel disease. Three cats had urinary tract infections diagnosed by urine culture and susceptibility testing prior to or during treatment. All patients had urine cytospin cytology performed; one case showed suspect urothelial carcinoma and three had no cytological evidence of neoplasia. All clients declined further sampling from the bladder masses. Therefore, cytologic/histologic diagnosis in all cases was not available. An abdominal ultrasound was performed in all cats, which revealed urinary bladder mass(es) prior to referral for RT. Three cats had pretreatment thoracic radiographs, which revealed no evidence of pulmonary metastasis. An abdominal CT was performed in all cases and one case had thoracic CT performed for staging. The thoracic CT showed a focal lesion of unknown etiology in the right caudal lung lobe. Palliative RT was performed with four weekly 6 Gy fractions (24 Gy in total). The urinary signs in all cats resolved over the course of RT: after the first RT treatment in two cats and after the second RT treatment in two cats. There were two Veterinary Radiation Therapy Oncology Group grade 1 gastrointestinal and one grade 2 genitourinary acute RT side effects.

RELEVANCE AND NOVEL INFORMATION

This is the first report in the literature of a standardized RT protocol as a treatment option for feline urinary bladder masses.

Canine Apocrine Gland Anal Sac Adenocarcinoma: A Review

Apocrine gland anal sac adenocarcinoma (AGASAC) is a relatively uncommon tumor in the dog and comprises approximately 17% of perianal malignancies; however, it is one of the most common causes of paraneoplastic hypercalcemia. Clinical signs in affected dogs most commonly are associated with mechanical obstruction caused by the primary tumor or enlarged regional metastatic lymph nodes and the effects of paraneoplastic hypercalcemia when present. Surgical excision of the primary tumor and metastasectomy of affected locoregional lymph nodes is the preferred initial treatment option for most dogs, although radiation therapy and adjuvant chemotherapy are commonly incorporated into multi-modality treatment plans. A significant role for the use of adjuvant chemotherapy has not been clearly demonstrated. Prolonged survival times are possible, especially for dogs with smaller primary tumors and for dogs that undergo further treatments for recurrent disease. In this article, we review the clinical signs, diagnosis, staging, treatment, and prognosis of AGASAC in the dog.

Minimal late radiation toxicity and transient early toxicity following postoperative definitive intent conformal radiation therapy (20 × 2.5 Gy) for canine apocrine gland anal sac adenocarcinoma

Postoperative radiation therapy (RT) may be beneficial for dogs with anal sac apocrine gland adenocarcinoma (ASAC). Clinically significant late toxicities have been reported in up to 65% of dogs with perianal tumors following non-conformal definitive RT, particularly when fractions of 3 Gy or higher are prescribed. The primary objective of this prospective, descriptive study was to evaluate tolerability of a novel 3D conformal RT (3DCRT) protocol in a group of dogs. Dogs with ASAC were prospectively enrolled if clients elected RT following surgery. The planning target volume was prescribed 50 Gy in 2.5 Gy fractions using 6 MV photons and administered over 26 days. Early and late radiation toxicities were graded according to standardized criteria. Thirteen dogs were initially enrolled but 1 was excluded due to a high risk of anesthesia-related mortality. Seven dogs presented with early stage disease. Median follow up time was 771 days (91-2223). Transient grade 3 dermatitis and anusitis developed in all dogs, with resolution within 4 weeks. Two dogs developed transient grade 2 late colitis. Locoregional failure in the irradiated field was documented in one dog at 738 days. All-cause median survival time was 771 days (95% confidence interval: 510 → 2223 days). Findings indicated that this fractionation may be safely administered to the canine anus and pelvic canal using 3DCRT, although acute toxicity should be anticipated. Further prospective studies are needed in order to confirm long-term tolerability and efficacy.

Investigation of the use of microwave ablation with and without cooling urethral perfusion for thermal ablation of the prostate gland in canine cadavers

OBJECTIVE

To investigate the use of microwave ablation (MWA) with cooling urethral perfusion and with no perfusion (MWA-UP and MWA-NP, respectively) for prostate gland ablation in canine cadavers.

ANIMALS

Cadavers of 18 sexually intact male dogs.

PROCEDURES

After technique refinement in 2 cadavers, laparotomy with ultrasound-guided MWA-UP (n = 8) or MWA-NP (8) of the prostate gland was performed in 16 cadavers. Normograde cystourethroscopy was performed before and after treatment; recorded images were reviewed in a blinded manner for scoring of urethral mucosal discoloration and loss of integrity. Difficulty with cystoscope insertion was recorded if present. Excised prostate glands were fixed for serial sectioning, gross measurements, and calculation of percentage ablation. Percentages of prostate tissue necrosis from MWA, denuded urethral mucosa, and depth of epithelial surface loss in an adjacent section of the colon were estimated histologically. Variables of interest were statistically analyzed.

RESULTS

Difficulty with cystoscope insertion after treatment was significantly more common and scores for urethral mucosal discoloration and loss of integrity were significantly higher (indicating more severe lesions) for the MWA-NP group than for the MWA-UP group. The histologically assessed percentage of denuded urethral mucosa was also greater for the MWA-NP group. Overall median percentage prostate gland ablation was 73%; this result was not associated with prostate gland volume or chronological order of treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

MWA-UP induced subtotal thermal necrosis of prostate glands in canine cadavers while limiting urethral mucosal injury. Further study is required to optimize the technique and evaluate its safety and efficacy in vivo as a future curative-intent treatment for prostatic tumors in dogs.

Retrospective assessment of radiation toxicity from a definitive-intent, moderately hypofractionated image-guided intensity-modulated protocol for anal sac adenocarcinoma in dogs

A recent calculation study predicted acceptable toxicity in pelvic organs at risk for a new definitive-intent, moderately hypofractionated radiation therapy (RT) protocol (12 x 3.8 Gy), when used with image-guided intensity-modulated radiation therapy (IG-IMRT). We hypothesized this protocol to result in clinically acceptable radiation toxicities. Dogs diagnosed with and irradiated for anal sac adenocarcinoma (ASAC) were retrospectively assessed. Eleven dogs were included, six had prior surgery. Before any therapy, staging according to Polton et al. resulted in the following distribution: stage 1 (n = 1), stage 2 (n = 1), stage 3a (n = 6), stage 3b (n = 3). We scored radiation toxicities at the end of therapy, at weeks 1, 3 and every 3 months after RT according to Veterinary Radiation Therapy Oncology Group radiation toxicity criteria. Clinical follow-up was maintained on regular intervals combined with computed tomography (n = 3). Median follow-up time for dogs still alive was 594 days (range: 224-972 days). Within 1 week post treatment, eight dogs (73%) developed grade 2 and four dogs (36%) grade 1 acute toxicity in the perianal region. All acute toxicities resolved or improved to grade 1 within 3 weeks after treatment. Late toxicity, for example, chronic colitis/diarrhoea, ulcerations, strictures or myelopathies was not observed in any patient. Five dogs were euthanized 105, 196, 401, 508 and 908 days after RT and six dogs were still alive, one in spite of progressive disease. The median progression-free survival was 908 days (95%CI: 215; 1602). The previous theoretically described definitive-intent, moderately hypofractionated protocol using IG-IMRT for the treatment of advanced ASAC showed clinically acceptable acute and late toxicities.

A combined protocol with piroxicam, chemotherapy, and whole pelvic irradiation with simultaneous boost volumetric modulated arc radiotherapy for muscle-invasive canine urinary transitional cell carcinoma: First clinical experience

The aims of this pilot study were to evaluate the feasibility and efficacy of high-dose hypofractionated volumetric modulated arc radiotherapy (VMAT) applied to whole pelvic region radiotherapy (WPRT) with multilevel simultaneous integrated boost (MLSIB) combined with piroxicam and chemotherapy for the treatment of canine transitional cell carcinoma (TCC) of the lower urinary tract with muscle invasion TCC. Twelve dogs were enrolled, according to stage, in two groups: group 1, TCC confined to the urinary tract; group 2, TCC with metastasis. The planning target volume dose was tailored from 36 to 42 Gy in 6 fractions. All dogs were prescribed piroxicam and radiosensitizing carboplatin, and six received chemotherapy after radiotherapy. Serial follow-ups with computed tomography and magnetic resonance imaging were performed. Disease control and toxicity effects were evaluated according to the Response Evaluation Criteria in Solid Tumors and Veterinary Radiation Therapy Oncology Group criteria. The treatment was well tolerated, and no high-grade side effects were reported. The median overall survival times for groups 1 and 2 were 1,230 and 150 days, respectively. A considerable percentage of patients in group1 (50%) were still alive at the time of writing this paper, and a longer follow-up could enable a more accurate survival analysis. This preliminary analysis shows that VMAT applied to the WPRT with MLSIB is an effective and safe option for dogs with lower urinary TCC, although the presence of metastases worsens the prognosis.

Long-term Consequences of Pelvic Irradiation: Toxicities, Challenges, and Therapeutic Opportunities with Pharmacologic Mitigators

A percentage of long-term cancer survivors who receive pelvic irradiation will develop treatment-related late effects, collectively termed pelvic radiation disease. Thus, there is a need to prevent or ameliorate treatment-related late effects in these patients. Modern radiotherapy methods can preferentially protect normal tissues from radiation toxicities to permit higher doses to targets. However, concerns about chronic small bowel toxicity, for example, still constrain the prescription dose. This provides strong rationale for considering adding pharmacologic mitigators. Implementation of modern targeted radiotherapy methods enables delivery of focused radiation to target volumes, while minimizing dose to normal tissues. In prostate cancer, these technical advances enabled safe radiation dose escalation and better local tumor control without increasing normal tissue complications. In other pelvic diseases, these new radiotherapy methods have not resulted in the low probability of normal tissue damage achieved with prostate radiotherapy. The persistence of toxicity provides rationale for pharmacologic mitigators. Several new agents could be readily tested in clinical trials because they are being or have been studied in human patients already. Although there are promising preclinical data supporting mitigators, no clinically proven options to treat or prevent pelvic radiation disease currently exist. This review highlights therapeutic options for prevention and/or treatment of pelvic radiation disease, using pharmacologic mitigators. Successful development of mitigators would reduce the number of survivors who suffer from these devastating consequences of pelvic radiotherapy. It is important to note that pharmacologic mitigators to ameliorate pelvic radiation disease may be applicable to other irradiated sites in which chronic toxicity impairs quality of life.

A technique to reduce skin toxicity in radiotherapy treatment planning for esophageal cancer

PURPOSE

To demonstrate a specific skin dose limiting technique in radiotherapy treatment planning for esophageal cancer and carry out a comparative analysis combining with clinical cases.

MATERIAL AND METHODS

Thirty patients with cervical and upper thoracic esophageal carcinoma previously treated in our institution were selected. A treatment plan had been finished previously according to the planning parameters directives from physician and delivered for each patient. In this study, we copied the previously delivered plans in radiotherapy treatment planning system and converted a low dose level (usually 5Gy) to a skin dose limiting structure (SDLS), then we set the objective functions of the SDLS in the Pinnacle Inverse Planning module and re-optimize the plans to reduce the skin doses. Finally, we compared the dose distribution and other parameters of target volume and organs at risk (OARs) between the old plans and the new plans.

RESULTS

There was no significant difference in most of OARs sparing. However, for all plans, the maximum dose to the SDLS decreased from 6145.90 ± 416.96 cGy to 5562.09 ± 616.69 cGy with maximum difference of 1361.30 cGy (P < 0.05), the percentage volume of 40Gy received by the SDLS decreased from (10.20 ± 6.36)% to (5.46 ± 4084)% with maximum difference of 9.89% (P < 0.05). For the target volume, there was no significant difference in the average dose and maximum dose, the approximate minimum dose to the target volume decreased from 5711.28 ± 164.61 cGy to 5584.93 ± 157.70 cGy (P < 0.05), the conformal index and homogeneity index of the target volume were hardly changed.

CONCLUSION

In radiotherapy treatment planning for esophageal cancer patients, the skin dose can be significantly reduced using the skin dose limiting technique, and the impact on the dose to target volume and OARs is little, this technique can be used in most radiotherapy treatment planning.

Definitive-intent intensity-modulated radiation therapy for treatment of canine prostatic carcinoma: A multi-institutional retrospective study

No standard of care is currently recognized for treatment of canine prostatic carcinoma (PC). This retrospective study assesses outcome following definitive-intent, intensity-modulated radiation therapy (RT) in dogs with PC. Medical records review was performed, including 18 patients from four institutions undergoing definitive-intent intensity-modulated radiotherapy to treat PC. Diagnosis was incidental in 7/18 (39%) patients. Five dogs (28%) had evidence of metastasis to loco-regional lymph nodes at diagnosis. Seventeen patients received concurrent non-steroidal anti-inflammatory drugs; 15/18 (83%) patients received maximally-tolerated dose (MTD) chemotherapy, with variable drugs and protocols employed. Total prescribed radiation dose ranged from 48 to 54 Gy (median 50 Gy) delivered as daily doses of 2.5-2.8 Gy. One patient was euthanized prior to completing radiotherapy. Acute toxicity was observed in nine patients; Grade 1-2 diarrhoea was the most common toxicity observed. Suspected late toxicity (urethral stricture, ureteral stricture and hindlimb oedema) was observed in three patients. Median event-free survival (EFS) following RT was 220 days, and median overall survival was 563 days. Local progression occurred in seven patients at a median of 241 days. Median overall survival was significantly longer in incidentally diagnosed dogs (581 vs 220 days in symptomatic dogs, P = .042). EFS was significantly longer in patients treated with MTD chemotherapy (241 vs 25 days, P < .001), and significantly shorter in patients presenting with evidence of metastatic disease (109 days) vs those without (388 days, P = .008). These findings suggest that definitive-intent radiotherapy is a valuable treatment option for local control of canine PC with moderate risk of toxicity.

A retrospective analysis of radiation oncology related scientific articles in the journal Veterinary Radiology and Ultrasound: Trends over 40 years (1976-2015)

The journal Veterinary Radiology & Ultrasound is a veterinary specialty journal devoted to the fields of veterinary diagnostic imaging and radiation oncology. The purpose of this retrospective, observational study is to evaluate progressive trends in radiation oncology articles published in Veterinary Radiology & Ultrasound during the 40-year period (1976-2015) and describe a shift of trends through several viewpoints. This 40-year period was divided into four subperiods: Period 1 (1976-1985), Period 2 (1986-1995), Period 3 (1996-2005), and Period 4 (2006-2015). These articles were divided into six categories based on the nature of the study: 1) studies related to teletherapy with endpoints being patient outcome, 2) radiation therapy dosimetry/planning, 3) patient setup, 4) reviews, 5) case reports, and 6) others. The number of radiation oncology articles in Veterinary Radiology & Ultrasound has increased over the 40-year period. The number of authors per article has increased between Periods 1 and 3. The number of articles related to linear accelerator has increased between Periods 3 and 4. The median number of treated patients per clinical article related to teletherapy ranged from 15 to 21, which has not changed significantly over the 40-year period. The most commonly used radiation therapy protocols during Periods 2 and 3 were fine-fractionated protocols (defined as 10 or more fractions), whereas coarse-fractionated protocols were more common during Periods 1 and 4. Findings from this study highlight the notable changes of trends in veterinary radiation oncology articles published in Veterinary Radiology & Ultrasound, which clearly reflect changes in the field of veterinary radiation oncology during the past 40 years.

Pharmacokinetics and toxicity of subcutaneous administration of carboplatin in poloxamer 407 in a rodent model pilot study

The objectives of this study were to assess the pharmacokinetics and safety of subcutaneously delivered carboplatin in poloxamer 407 in rats. Carboplatin (5mg/rat) in 0.5ml poloxamer 407 (1.0 ml total volume) was administered subcutaneously in a right subcutaneous perineal incision in all 12 treatment rats. Three control rats received 1.0 ml of poloxamer 407. Total platinum was measured in plasma q24hrs from 0 to 168hrs. Protein-unbound platinum was measured in plasma at 168hrs. After sacrifice on day 7, total platinum was determined in wound bed muscle. Platinum concentrations in all samples were measured by ICP-MS. Wounds were visually assessed daily for 7 days. Perineal tissues (full wound bed including muscle, subcutis, skin) were assessed histologically and scored. Total platinum was detectable in plasma from 24 to 168 hrs. Total plasma platinum AUC and C_max were 9,165.3 ng/mL•h and 129.4 ng/mL. Day 7 total platinum concentration in muscle was approximately 10-fold higher than total plasma platinum concentration. No unbound platinum was detected in plasma samples at 168 hours. No wound healing complications were detected at any time point, nor was tissue necrosis observed histologically. The results of this study suggest that subcutaneous carboplatin in poloxamer 407 can be used in vivo providing direct tissue exposure to carboplatin without significant local effects or systemic absorption and without wound healing complications.

Complete Resolution of a Recurrent Canine Anal Sac Squamous Cell Carcinoma with Palliative Radiotherapy and Carboplatin Chemotherapy

Anal sac squamous cell carcinoma (SCC) is a rare tumor in dogs. Only eight cases have been described in the literature, and previous reports of treatment only describe surgery or palliative treatment with non-steroidal anti-inflammatory drugs. We report a case of a 12-year-old female neutered Labrador with locally advanced anal sac SCC. The dog was treated with four cycles of carboplatin 300 mg/m² and four weekly fractions of 8.5 Gy radiation. The dog achieved a complete response, and one year later the dog is still alive and well with no evidence of tumor recurrence. Radiotherapy in combination with carboplatin chemotherapy was effective in the long-term control of this rare disease.

Management of Radiation Side Effects to the Skin

Radiation therapy (RT) is an essential component for management of many cancers. Veterinary health care professionals must counsel owners about the potential side effects of RT, the anticipated management plan, and associated costs. For most veterinary patients treated with RT, acute radiation side effects are mild; however, careful radiation treatment planning and appropriate management of acute side effects are essential to try to prevent chronic sequelae and the need for ongoing wound care. This article reviews acute and late side effects to the skin and their management.

Outcome in dogs with advanced (stage 3b) anal sac gland carcinoma treated with surgery or hypofractionated radiation therapy

Stage 3b anal sac gland carcinoma (ASGC) can be life-threatening. A surgical approach is not always possible or may be declined. Dogs with stage 3b ASGC treated with surgery or conformal radiation therapy (RT) with 8 × 3.8 Gy (total dose 30.4 Gy, over 2.5 weeks) were retrospectively evaluated. Patient characteristics, median progression-free interval (PFI) and median survival time (MST) were compared. Twenty-eight dogs were included; 15 underwent surgery, 13 underwent RT. At the time of presentation, 21% showed life-threatening obstipation and 25% showed hypercalcaemia. PFI and MST for surgery cases were 159 days (95% CI: 135-184 days) and 182 days (95% CI: 146-218 days), both significantly lower than for RT cases with 347 days (95% CI: 240-454 days) and 447 days (95% CI: 222-672 days), (P = 0.01, P = 0.019). Surgery as well as RT led to a fast relief of symptoms. PFI and survival of surgical patients were significantly inferior to that of a comparable patient group treated with conformal hypofractionated RT.

Treatment of advanced canine anal sac adenocarcinoma with hypofractionated radiation therapy: 77 cases (1999-2013)

Currently no standard of care exists for advanced, inoperable or metastatic anal sac adenocarcinoma (ASAC). The objective of this retrospective study was to assess the role of hypofractionated radiation therapy (RT) in 77 dogs with measurable ASAC. A total of 38% of dogs experienced a partial response to RT. For dogs presenting with clinical signs related to the tumour, improvement or resolution of signs was noted in 63%. For dogs presenting with hypercalcemia of malignancy, resolution was noted in 31% with RT alone and an additional 46% with radiation, prednisone, and/or bisphosphonates. Median overall survival was 329 days (range: 252-448 days). Median progression free survival was 289 days (range: 224-469). There was no difference in survival based on radiation protocol, use of chemotherapy, previous surgery or advanced stage. Radiation toxicities were mild and infrequent. Hypofractionated RT is well tolerated and is applicable in the treatment of advanced primary, locoregional or metastatic ASAC.

TOLERABILITY AND TUMOR RESPONSE OF A NOVEL LOW-DOSE PALLIATIVE RADIATION THERAPY PROTOCOL IN DOGS WITH TRANSITIONAL CELL CARCINOMA OF THE BLADDER AND URETHRA

Previously reported radiation protocols for transitional cell carcinoma of the canine lower urinary tract have been ineffective or associated with increased side effects. Objectives of this retrospective, cross-sectional study were to describe safety of and tumor responses for a novel palliative radiation protocol for transitional cell carcinoma in dogs. Included dogs had cytologically or histologically confirmed transitional cell carcinoma of the bladder or urethra, and were treated with 10 once-daily fractions (Monday-Friday) of 2.7 Gy. Thirteen dogs were sampled, with six treated using radiation as first-line (induction) therapy and seven treated using radiation as rescue therapy after failing previous chemotherapy. Within 6 weeks of radiation, 7.6% (1/13) dogs had a complete response, 53.8% (7/13) partial response, 38.5% (5/13) stable disease, and none had progressive disease. Three patients presenting with urethral obstruction had spontaneous micturition restored during the treatment protocol. A single patient with unilateral ureteral obstruction was patent at recheck examination. Median survival time from time of initial diagnosis was 179 days. Median survival time from start of radiation was 150 days. Acute radiation side effects occurred in 31% (4/13) patients and were classified as grade 1 or 2. No significant late side radiation side effects were reported. No variables examined were identified as prognostic factors. Findings indicated that the reported radiation protocol was safe in this sample of dogs with bladder and urethral transitional cell carcinoma. Future prospective studies are needed to determine utility of this treatment as a rescue therapy in patients with complete urinary tract obstruction.

Therapeutic options for the treatment of chronic pain in dogs

Chronic pain is a widely recognised problem in humans and is being increasingly recognised as a significant problem in dogs. Whilst a large number of therapies are described and utilised to treat chronic pain in dogs, there is a severe shortage of evidence to guide practitioners in selection of treatments. Until more evidence becomes available, practitioners should adopt a cautious approach, utilising licensed treatments first when possible. Non-pharmacological therapies should be incorporated into the chronic pain management plan whenever possible. Given the probable prevalence of chronic pain in dogs there is an urgent need for research to identify effective treatments.

Comparative wound healing--are the small animal veterinarian's clinical patients an improved translational model for human wound healing research?

Despite intensive research efforts into understanding the pathophysiology of both chronic wounds and scar formation, and the development of wound care strategies to target both healing extremes, problematic wounds in human health care remain a formidable challenge. Although valuable fundamental information regarding the pathophysiology of problematic wounds can be gained from in vitro investigations and in vivo studies performed in laboratory animal models, the lack of concordance with human pathophysiology has been cited as a major impediment to translational research in human wound care. Therefore, the identification of superior clinical models for both chronic wounds and scarring disorders should be a high priority for scientists who work in the field of human wound healing research. To be successful, translational wound healing research should function as an intellectual ecosystem in which information flows from basic science researchers using in vitro and in vivo models to clinicians and back again from the clinical investigators to the basic scientists. Integral to the efficiency of this process is the incorporation of models which can accurately predict clinical success. The aim of this review is to describe the potential advantages and limitations of using clinical companion animals (primarily dogs and cats) as translational models for cutaneous wound healing research by describing comparative aspects of wound healing in these species, common acute and chronic cutaneous wounds in clinical canine and feline patients, and the infrastructure that currently exists in veterinary medicine which may facilitate translational studies and simultaneously benefit both veterinary and human wound care patients.

Three-dimensional conformal versus non-graphic radiation treatment planning for apocrine gland adenocarcinoma of the anal sac in 18 dogs (2002-2007)

Differences in dose homogeneity and irradiated volumes of target and surrounding normal tissues between 3D conformal radiation treatment planning and simulated non-graphic manual treatment planning were evaluated in 18 dogs with apocrine gland adenocarcinoma of the anal sac. Overall, 3D conformal treatment planning resulted in more homogenous dose distribution to target tissues with lower hot spots and dose ranges. Dose homogeneity and guarantee of not under-dosing target tissues with 3D conformal planning came at the cost, however, of delivering greater mean doses of radiation and of irradiating greater volumes of surrounding normal tissue structures.

Treatment and outcome of four cats with apocrine gland carcinoma of the anal sac and review of the literature

Anal sac adenocarcinoma is uncommon in cats. We report the outcome of multi-modality therapy in two cats (surgery, definitive radiotherapy and systemic chemotherapy) and surgery alone in two cats. All received surgical excision of the primary tumour followed by radiotherapy and carboplatin chemotherapy in two cases. Both cats that underwent multimodal therapy developed distant metastatic disease and one developed recurrence of the primary tumour. One cat that underwent surgery alone with incomplete margins also developed rapid recurrence. Overall survival times were 89, 161 and 169 days. One cat that had complete surgical excision is still alive without recurrence 425 days postoperatively. Whilst the role of radiation in the local control of this disease is yet to be defined, clearly a more effective systemic therapy is required before such aggressive local treatment can be routinely recommended.

Balloon dilation and intralesional steroid for benign rectal stricture management in a cat

A 4-year-old castrated male domestic shorthair presented for 1 week of constipation and tenesmus. A rectal stricture had been diagnosed 8 months prior at the time of adoption and the cat had been successfully managed with stool softeners until presentation. A complete diagnostic work-up failed to reveal an underlying etiology for the stricture and colonoscopy was performed. Endoscopic biopsies of the stricture revealed benign non-specific inflammatory changes. Balloon dilation of the rectal stricture was performed during the initial colonoscopy and 3 and 9 days later. Triamcinolone acetonide was injected into the stricture site with endoscopic guidance during the third dilation procedure. The patient has been monitored for over 27 months; follow-up indicates no signs of tenesmus and repeated rectal examinations reveal no stricture recurrence. This case report demonstrates that endoscopic balloon dilation with intralesional steroid injection represented a minimally invasive and effective option for the treatment of a benign rectal stricture in this cat, and deserves further prospective investigation.