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  • Author or Editor: A. P. Théon x
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Summary:

Seventy-seven dogs with malignant tumors of the nasal and paranasal cavities were treated by use of radiotherapy. The tumors included carcinomas (58) and sarcomas (19). Radiographic findings, including site of involvement and tumor extension, were the basis of clinical staging. Staging was performed according to the tumor, node, metastasis staging of the World Health Organization, and a modified staging scheme based on prognostic factors that seemed to correlate best with response to treatment. All irradiations were done with a telecobalt 60 unit. Fifty-six dogs were treated with irradiation alone, and 21 had partial tumor resection prior to radiotherapy. Treatment dose was 48 Gy (minimal tumor dose) administered on a Monday-Wednesday-Friday basis at 4 Gy/fraction over 4 weeks. The irradiation technique emphasized rostral field with a generous treatment volume. Duration of follow-up after irradiation ranged from 1 month to 61 months. The 1- and 2-year overall survival rates were 60.3% and 25%, respectively, and the 1- and 2-year relapse-free survival rates were 38.2% and 17.6%, respectively. Results of histologic examination and our modified staging scheme were significant (P = 0.02 and P = 0.04, respectively) prognostic factors of relapse-free survival. Conversely, tumor site, tumor extension, World Health Organization clinical stage, and cytoreductive surgery prior to irradiation did not affect the outcome of treatment. According to our modified staging scheme, dogs with stage-2 disease have a poorer prognosis than dogs with stage-1 disease, with a relative risk of relapse 2.3-fold higher. Dogs with carcinoma had a poorer prognosis than dogs with sarcoma (predominantly chondrosarcoma) with a relative risk of relapse 3.3-fold higher. Furthermore, dogs with chondrosarcomas fared significantly (P = 0.05) better than those with adenocarcinomas. Most acute radiation reactions were acceptable. Chronic ocular complications were seen in 45% (35/77) of the dogs.

Free access
in Journal of the American Veterinary Medical Association

Summary

Twenty-seven horses (and 1 mule) with 32 histologically confirmed cutaneous tumors were studied to evaluate the effects of intratumoral injection of cisplatin initiated at the time of surgery. As a result of surgery, 9 of the wounds were closed primarily (5 sarcoids, 4 carcinomas) and 23 were left open to granulate (16 sarcoids, 6 carcinomas, 1 hamartoma). Chemotherapy consisted of 4 treatment sessions of intratumoral injection of cisplatin in purified sesame oil at 2-week intervals. The first treatment session was administered intraoperatively. A controlled-release formulation of cisplatin in sesame oil was used to limit drug egress from the injection site. Dosage was 1 mg of cisplatin/cm3 of tissue. The mean relapse-free interval was 41 ± 3.7 months. The estimates of overall relapse-free survival rates were 92 ± 5% at 1 year and 77 ± 11% at 4 years. Cisplatin-related local toxicosis was minimal and wound healing was not compromised. Intratumoral injection of cisplatin appears safe and effective when administered in the perioperative period for selected tumors in equidae.

Free access
in Journal of the American Veterinary Medical Association

Summary

Nine dogs and 9 cats with ceruminous gland carcinoma were evaluated to determine whether they would receive radiation therapy. Tissue samples were reviewed to confirm the diagnosis and to assess completeness of resection in animals that had undergone surgery. Seven animals were excluded because surgical excision was determined histologically to have been complete (5) or because the owners did not wish to pursue treatment, because of advanced disease (2). The remaining 6 cats and 5 dogs, 6 of which had previously undergone surgery, were included in the study. The radiation therapy dose was 48 Gy, given in 12 fractions over 4 weeks. The product-limit estimate of mean progression-free survival time was 39.5 months. The estimate of 1-year progression-free survival rate was 56%. The tumor recurred in 4 animals, and metastases were observed in 3 animals. Radiation therapy was found to be safe and effective.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess the influence of tumor cell proliferation and sex-hormone receptors on the efficacy of megavoltage irradiation for dogs with incompletely resected meningiomas.

Design—Longitudinal clinical trial.

Animals—20 dogs with incompletely resected intracranial meningiomas.

Procedure—Dogs were treated with 48 Gy of radiation administered 3 times per week on an alternateday schedule of 4 Gy/fraction for 4 weeks, using bilateral parallel-opposed fields.

Results—Tumor proliferative fraction measured by immunohistochemical detection of proliferating cell nuclear antigen (PFPCNA index) ranged from 10 to 42% (median, 24%). Progesterone receptor immunoreactivity was detected in 70% of tumors. Estrogen receptor immunoreactivity was not detected. An inverse correlation was found between detection of progesterone receptors and the PFPCNA index. The overall 2-year progression-free survival (PFS) rate was 68%. The only prognostic factor that significantly affected PFS rate was the PFPCNA index. The 2-year PFS was 42% for tumors with a high PFPCNA index (value ≥ 24%) and 91% for tumors with a low PFPCNA index (value < 24%). Tumors with a high PFPCNA index were 9.1 times as likely to recur as were tumors with a low PFPCNA index.

Conclusions and Clinical Relevance—This study confirms the value of irradiation for dogs with incompletely resected meningiomas. Prognostic value of the PFPCNA index suggests that duration of treatment and interval from surgery to start of irradiation may affect outcome. Loss of progesterone receptors in some tumors may be responsible for an increase in PFPCNA index and may indirectly affect prognosis after radiation therapy. (J Am Vet Med Assoc 2000;216: 701–707)

Full access
in Journal of the American Veterinary Medical Association

Summary

Sixteen cats with malignant tumors (10 carcinomas, 6 sarcomas) of the nasal cavity and paranasal sinuses were treated with curative intent by radiotherapy. Clinical staging was based on radiographic findings, using the tumor, node, metastasis classification system of the World Health Organization. Irradiation was done with a telecobalt-60 unit (13 cats) and an orthovoltage unit (3 cats). Fourteen cats were treated with irradiation alone, and 2 cats had incomplete surgical resections prior to radiotherapy. Treatment dose was 48 Gy (minimum tumor dose), administered by use of 4 Gy per fraction on a Monday/Wednesday/Friday basis over 4 weeks. Survival times after treatment ranged from 1 to 36 months. The 1- and 2-year overall survival rates were 44.3 and 16.6%, respectively. Histologic type and clinical stage did not have prognostic value. Most acute radiation reactions were mild and self-limiting. Chronic ocular complications were seen in 3 cats. These treatment responses compared favorably with those previously described in dogs and cats with intranasal neoplasms treated with teletherapy and provided a perspective for comparison of new treatment methods.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the incidence of bovine papillomavirus (BPV) type 1 or 2 in sarcoids and other samples of cutaneous tissues collected from horses in the western United States.

Animals—55 horses with sarcoids and 12 horses without sarcoids.

Procedure—Tissue samples (tumor and normal skin from horses with sarcoids and normal skin, papillomas, and nonsarcoid cutaneous neoplasms from horses without sarcoids) were collected. Tissue samples were analyzed for BPV-1 or -2 DNA, using a polymerase chain reaction (PCR) and restriction fragment length polymorphism. The PCR products from 7 sarcoid- affected horses were sequenced to evaluate percentage homology with expected sequences for BPV-1 or -2.

Results—Most (94/96, 98%) sarcoids contained BPV DNA. Sixty-two percent of the tumors examined had restriction enzyme patterns consistent with BPV-2. Thirty-one of 49 (63%) samples of normal skin obtained from horses with sarcoids contained BPV DNA. All samples subsequently sequenced had 100% homology with the expected sequences for the specific viral type. All tissues from healthy horses, nonsarcoid neoplasms, and papillomas were negative for BPV DNA.

Conclusions and Clinical Relevance—Bovine papillomaviral DNA was detected in essentially all sarcoids examined. There appears to be regional variation in the prevalence of viral types in these tumors. The fact that we detected viral DNA in normal skin samples from horses with sarcoids suggests the possibility of a latent viral phase. Viral latency may be 1 explanation for the high rate of recurrence following surgical excision of sarcoids. (Am J Vet Res 2001;62:741–744)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine expression of a transforming gene (E5) of bovine papillomavirus in sarcoids, other tumors, and normal skin samples collected from horses with and without sarcoids.

Sample Population—23 sarcoids and 6 samples of normal skin obtained from 16 horses with sarcoids, 2 samples of normal skin and 2 papillomas obtained from horses without sarcoids, and 1 papilloma obtained from a cow.

Procedure—Protein was extracted from tissue samples collected from horses and incubated with agarose beads covalently coupled to Staphylococcus aureus protein A and an anti-E5 polyclonal antibody. Following incubation, proteins were eluted from the beads and electrophoresed on a 14% polyacrylamide gel and transferred to a polyvinylidene difluoride membrane. The E5 protein was detected by use of western blot analysis, using a chemiluminescence detection system.

Results—All 23 sarcoids had positive results for expression of E5 protein. Quantity of viral protein appeared to vary among sarcoids. All other tissues examined had negative results for E5 protein. Highest expression for E5 protein was observed in biologically aggressive fibroblastic variants of sarcoids, compared with expression in quiescent tumors.

Conclusions and Clinical Relevance—This study documented that activation and expression of the E5 gene is evident in sarcoids obtained from horses. These data support the conclusion that infection with bovine papillomavirus is important in the initiation or progression of sarcoids in horses. Treatment strategies designed to increase immune recognition of virally infected cells are warranted. (Am J Vet Res 2001;62:1212–1217)

Full access
in American Journal of Veterinary Research

Abstract

Objective

To compare therapeutic benefits of intratumoral administration of cisplatin and bleomycin for squamous cell carcinoma of the eyelids in horses.

Animals

25 horses with 27 T2-stage periocular squamous cell carcinomas.

Procedure

Horses were treated 4 times at 2-week intervals with a slow-release formulation of cisplatin (1 mg/cm3 of tissue) or bleomycin (1 IU/cm3 of tissue). A two-stage design was used to minimize the sample size in each treatment arm.

Results

The local control rate at 1 year for lesions treated with cisplatin was 93 ± 6%, and with bleomycin was 78 ± 10%. Difference in local control duration between the 2 treatment groups was not significantly different. A high tumor proliferative fraction index value was associated with a higher local (in-field) control rate, but also with a higher risk of marginal and regional recurrences. Tumors with a low proliferative fraction index value (< 28%) had 9.5-times higher (P = 0.0411) risk of recurrence than those with a high index value. Local acute reactions were similar in the 2 treatment groups, and chronic reactions were not observed.

Conclusions

Cisplatin and bleomycin were effective anticancer agents for carcinoma of the eyelid in horses. Based on therapeutic benefit and treatment cost, cisplatin was found to be a better choice for intratumoral chemotherapy of eyelid carcinomas.

Clinical Relevance

Results of this study confirm the value of intratumoral chemotherapy, using cisplatin, for treatment of cutaneous squamous cell carcinomas in horses. (Am J Vet Res 1997;58:431–436)

Free access
in American Journal of Veterinary Research

  • The most common cause of naturally developing acromegaly in cats is a growth hormone-secreting adenoma of the pituitary pars distalis somatotropic cells.

  • Irradiation of pituitary gland tumors in cats with acromegaly may result in transient or long-term resolution of acromegaly and diabetes mellitus.

  • Diabetic cats with acromegaly may have a history of weight loss instead of weight gain.

Free access
in Journal of the American Veterinary Medical Association