External-beam Co-60 radiotherapy for canine nasal tumors: a comparison of survival by treatment protocol

A retrospective analysis of survival times in dogs with intranasal tumors was performed comparing those treated using hypofractionated or full course Co-60 radiotherapy protocols alone or with surgical adjuvant therapy and those receiving no radiation treatment. One hundred thirty-nine dogs presented to the University of Minnesota Veterinary Medical Center for treatment of histologically-confirmed nasal neoplasia between July 1983 and October 2001 met the criteria for review. Statistically analyzed parameters included age at diagnosis, tumor histologic classification, fractionation schedule (number of treatments, and number of treatment days/week) (classified as hypofractionated if 2 or less treatments/week); calculated minimum tumor dose/fraction; calculated total minimum tumor dose (classified as hypofractionated if less than 37 Gy in six or fewer fractions); number of radiotherapy portals, a treatment gap of more than 7 days in a full course (3-5 treatments/week, 3-3.5 week treatment time) radiotherapy protocol, the influence of eye shields on survival following single portal DV fields, the survey radiographic extent of the disease, and the presence or absence of cytoreductive surgery. There was a significant relationship only between protocols using 3 or more treatments/week and at least 37 Gy cumulative minimum tumor dose and survival. However, there was no significant relationship between either total minimum tumor dose or dose/fraction and survival and there were no significant relationships between survival and any of the other variables analyzed including tumor histologic type.     

Radiotherapy of a recurrent ossifying fibroma in the paranasal sinuses of a horse

A 7-year-old female Thoroughbred was admitted with a history of labored breathing, stridor, and exercise intolerance. Examination revealed a mass in the left paranasal sinuses that was determined to be an ossifying fibroma. Initial treatment consisted of surgical removal of the mass alone; however, the mass recurred 9 months after surgery. The mass was again removed, and adjunctive radiotherapy consisting of 3,000 cGy of cobalt radiation was administered. This time, the tumor did not recur for > 6 years. A third surgery was performed to remove the mass, and adjunctive radiotherapy consisting of 4,000 cGy of photon beam radiation from a linear accelerator was administered. The mass did not recur during the subsequent 3 years. Ossifying fibromas are uncommon tumors that frequently recur if incompletely excised. Results in this horse suggest that adjunctive radiotherapy may delay or prevent tumor recurrence in affected horses.     

Surgical and Localized Radiation Therapy for an Intranasal Adenocarcinoma in a Rabbit

An 8-year-old spayed female Netherland Dwarf rabbit presented with a two-month history of dyspnea and snoring. A computed tomography (CT) scan of the head revealed mass lesions in the right nasal cavity. Surgical exenteration of the lesions was performed, and the histopathological diagnosis was an intranasal adenocarcinoma. On the basis of this diagnosis, radiotherapy was planned and consisted of eight fractions of 6 Gy administered once a week. After the completion of radiation therapy, the soft tissue density in the right nasal cavity, as detected by CT, significantly decreased. The prognosis has remained good for over 3 years after treatment. This paper is the first to describe the clinical and pathological features of an intranasal tumor in a rabbit.     

Effects of radiotherapy on pituitary corticotroph macrotumors in dogs: a retrospective study of 12 cases

The efficacy of low doses of radiotherapy for the treatment of pituitary corticotroph macrotumors in dogs is evaluated retrospectively. Twelve dogs with pituitary-dependent hyperadrenocorticism and a large pituitary tumor treated with 36 Gy of radiation were included. Radiation was delivered in 12 fractions of 3 Gy over a 4- to 6-week period. Effects of radiation therapy on tumor size were assessed by computed tomography scans; a decrease was observed in 11 dogs (decrease > 50% in 6 dogs). Three dogs were reirradiated due to major tumor regrowth or a lack of tumor decrease (mean total dose: 22 Gy given in 3-Gy fractions over 3 or 4 weeks). The mean and median survival times following the initiation of radiotherapy were 22.6 months (688 days) and 17.7 months (539 days), respectively. These data are consistent with previous findings, based on high-dose radiation, showing that radiotherapy is a useful option for treating pituitary corticotroph macrotumors in dogs. Furthermore, computed tomography follow-up of the treated dogs demonstrates objectively the efficacy of radiotherapy against corticotroph tumors in dogs.     

Combined use of surgery and radiation in the treatment of an intradural myxoid liposarcoma in a dog

An intradural-extramedullary myxoid liposarcoma of the high cervical spine was diagnosed in a 9-year-old, spayed female Cavalier King Charles spaniel that was presented for a 2-month history of cervical pain and tetraparesis. Radiation therapy applied after surgery resulted in complete remission of the neurological deficits. The tumor recurred 18 months after surgical excision. A second surgery and another course of radiotherapy again resulted in complete remission of the clinical signs. The dog was euthanized 11 months after the second surgery because of tumor recurrence.     

Management of pleural effusion secondary to metastatic adenocarcinoma in a dog

A 4-year-old spayed Collie-type dog was evaluated for pleural effusion secondary to metastatic adenocarcinoma with no identifiable primary tumor. For 48 weeks, chemotherapy and thoracentesis palliated clinical signs associated with pleural effusion. At week 49, 5 mCi of chronic phosphate P32 (32P) suspension was injected into the right pleural space. Pleural effusion was not detected for 14 weeks after 32P administration (week 63). In week 64, 32P suspension was readministered by injecting 7.5 mCi into the right hemithorax and 2.5 mCi into the left. Pleural effusion was again detected 3 weeks later (week 67), and the dog was treated with additional chemotherapy. Death, at week 72, was caused by disseminated intravascular coagulopathy.     

Radiotherapy of Metastatic Seminoma in the Dog Case Reports

Four dogs with metastatic seminoma were treated with cesium 137 teleradiotherapy. Minimum total tumor dose ranged from 17 to 40 gray (Gy) and was usually given through bilateral opposing sublumbar ports in eight to ten fractions, with three fractions given weekly. The tumor regressed in all four dogs. The first dog (case 1) was free of tumor and died of non-tumor related causes at 57 months. The second dog (case 2) was free of tumor but was euthanatized at 37 months for a limb fracture. The third dog (case 3) was euthanatized for undertermined pulmonary disease 43 months after radiotherapy. The fourth dog (case 4) was euthanatized 6 months following radiotherapy because of transitional cell carcinoma and renal failure. No evidence of seminoma was found at necropsy. Radiotherapy was shown to be effective treatment for seminoma with regional metastasis.     

Bleomycin chemotherapy for metastatic squamous cell carcinoma in a ferret.

Bleomycin, an antitumor antibiotic, was effective in temporarily reducing the size of a metastatic squamous cell carcinoma in a ferret. The tumor had recurred after previous excision and had metastasized to the right submandibular lymph node. The ferret was treated without effect at a dosage of 10 U/m2, sc, once a week. The dosage was increased to 20 U/m2 once a week, and reduction of tumor size was observed.     

PALLIATIVE RADIOTHERAPY FOR CANINE APPENDICULAR OSTEOSARCOMA

Fifteen dogs with appendicular osteosarcoma (presumptive diagnosis, n = 6 dogs; biopsy confirmed, n = 9 dogs) were treated with palliative radiotherapy. Treatment entailed a total of three 10 Gy fractions of ⁶⁰Co radiation delivered over a three week period on days 0, 7 and 21, for a total dose of 30 Gy. Twelve dogs experienced improvement in limb function 7–22 days after the start of treatment. Long term followup was available for nine of the twelve responders. The duration of response was 17–288 days (n = 9 dogs; median = 130 days; mean = 116 days). Response duration did not appear to be related to initial tumor size. Palliative radiotherapy can result in improved limb function in dogs with appendicular osteosarcoma.     

Treatment of a recurrent ocular squamous cell carcinoma in a horse with Iridium-192 implantation

A 7-year-old Selle français gelding was presented for a recurrent conjunctival tumour on the left eye. A previous histologic analysis revealed a conjunctival squamous cell carcinoma. As it was the third recurrence after surgical excision in a 1½-year period, we decided to perform interstitial radiotherapy combined with the surgical excision. Two Iridium-192 pins were implanted in the subcutaneous fascia of the lower eyelid over the tumor site and were removed 3 days later. No postoperative adverse reactions were observed. Twelve months postoperatively, there were no signs of local recurrence. Surgical excision combined with Iridium-192 therapy appeared to be an effective treatment in this case.     

Use of recombinant human interferon alpha-2a in the management of a dog with epitheliotropic lymphoma

An 8-year-old, mixed-breed dog with preputial epitheliotropic lymphoma was initially treated with cyclophosphamide, vincristine, and prednisolone. A short-term partial response was followed by disease progression after 4 weeks. Recombinant human interferon alpha-2a was administered starting at week 7. The interferon therapy resulted in rapid resolution of clinical signs and a 10-week disease-free interval. The lymphoma recurred at 17 weeks and did not respond to rescue chemotherapy. Additional oral lesions were treated with localized radiotherapy followed by increased dosages of interferon. This additional interferon treatment resulted in another 12 weeks of stable disease.     

Secondary chronic respiratory acidosis in a dog following the cervical cord compression by an intradural glioma

An intradural tumor in the upper cervical region was found in a dog with quadriparesis and chronic respiratory acidosis. Surgical removal of the tumor in the atlas and intraoperative radiotherapy were attempted. The tumor was histologically diagnosed as a neural glioma. A preoperative acid-base disturbance was dramatically improved after surgery. The clinical changes appeared in this case suggest that compression of the spinal cord at this region may cause paralysis of the respiratory muscles and secondarily result in chronic respiratory acidosis following the respiratory insufficiency.     

Combined treatment of ocular squamous cell carcinoma in a horse, using radiofrequency hyperthermia and interstitial 198Au implants

Unilateral ocular squamous cell carcinoma in a horse was treated effectively with a combination of repeated radiofrequency hyperthermia and interstitial radiotherapy. These 2 modalities of treatment are synergistic. Interstitial irradiation was achieved, using 198Au implants to deliver a total dose of approximately 5,000 rads/implant over an area of 1 cm2. Radio frequency hyperthermia was repeated 3 times, and radiotherapy was used twice. Treatment resulted in complete regression of the tumor, and ocular complications have not been seen.     

Exogenous Insulin Treatment after Hypofractionated Radiotherapy in Cats with Diabetes Mellitus and Acromegaly

Background: The optimal treatment for feline acromegaly has yet to be established. Surgical and medical therapies are minimally effective although radiotherapy might have greater efficacy. The purpose of this study was to review the response and outcome of cats with acromegaly and insulin-resistant diabetes mellitus (DM) to radiotherapy.
Hypotheses: That radiotherapy improves glycemic control in cats with acromegaly and that improved glycemic control is due to remission of clinical acromegaly; demonstrated by a fall in serum insulin-like growth factor-1 (IGF-1) concentrations.
Animals: Fourteen cats with naturally occurring acromegaly.
Methods: Retrospective case review; records of all cats treated for acromegaly with radiotherapy were reviewed from 1997 to 2008. Cats were selected on the basis of compatible clinical signs, laboratory features, and diagnostic imaging findings. Fourteen cats received radiotherapy, delivered in 10 fractions, 3 times a week to a total dose of 3,700 cGy.
Results: Thirteen of 14 cats had improved diabetic control after radiotherapy. These improvements were sustained for up to 60 months. DM progressed in 2 cats and 1 did not respond. Seven cats responded before the final treatment. Ten cats were euthanized, 1 as a consequence of radiotherapy. In 8 cats in which IGF-1 was measured after treatment, changes in its concentration did not reflect the clinical improvement in glycemic control.
Conclusions and Clinical Importance: Radiotherapy represents an effective treatment for cats with insulin-resistant DM resulting from acromegaly. IGF-1 concentration after treatment does not provide a suitable method by which remission from either acromegaly or insulin-resistant DM may be assessed.     

Use of radiotherapy for the treatment of intranasal tumors in cats: six cases (1980-1985)

Six cats with intranasal neoplasia treated with radiotherapy were evaluated. The mean survival time from the initiation of radiotherapy was 19 months, with 2 cats still known to be alive. Two cats died for reasons unrelated to the primary tumor. One cat had no clinical evidence of nasal tumor 41 months after treatment, but was lost to further follow-up evaluation.     

Carboplatin for treatment of a Sertoli cell tumor in a mallard (Anas platyrhynchos)

A 13‐year‐old male mallard was diagnosed with a non‐resectable Sertoli cell tumor involving the left testis. The duck was treated with four doses of single‐agent carboplatin given at 4‐ to 5‐week intervals. Heteropenia, 2 weeks after each treatment, was the acute dose‐limiting toxicity. The tumor reduced in size by 25%, and the duck's clinical condition improved for 12 months. Sertoli cell tumors are rare in birds, and this is the first report, to our knowledge, of attempted chemotherapy treatment in the veterinary literature.     

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.     

Mast cell tumor in the nasal cavity of a dog

An 11-year-old male Shetland sheepdog displayed epistaxis and nasal discharge from the left nasal foramen. Cytological examination of a smear sample obtained by rhinotomy revealed neoplastic mast cells in the nasal cavity, a definitive diagnostic sign of mast cell tumor. The case was treated by surgery combined with radiotherapy and chemotherapy. Eighteen days after the last treatment, marked enlargement of the mandibular lymph nodes and facial edema developed, and the dog was euthanized at the owner's request. At necropsy, metastatic proliferation of mast cells was confirmed in the lymph nodes and liver, but no neoplastic mast cells were observed in the nasal cavity.     

An end‐to‐end urethral anastomosis after inguinal tunnelization: a new technique in a dog

An 8‐year‐old male dog was presented with a peri‐urethral intrapelvic mass with the characteristics of a sarcoma on computed tomography and cytology evaluation. A two‐step procedure leading to a permanent urinary diversion was performed. During the same procedure, the caudal pelvic urethra and mass were resected and an extrapelvic anastomosis of the pelvic portion of the urethra to its penile portion was performed after passage of the pelvic urethra through the inguinal canal. The procedure successfully produced a tension‐free end‐to‐end urethral anastomosis and no complications were observed during the postoperative period. Histologically, the lesion was reported as a narrowly excised liposarcoma. A 4‐week course of curative intent of radiotherapy was initiated 2 weeks after surgery. Eight months later, the dog was free of clinical signs.