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  • Author or Editor: Alain P. Théon x
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Abstract

Objective—To determine quality and duration of progression-free survival (PFS) time in dogs with unresectable thyroid carcinomas treated with definitive megavoltage irradiation and analyze prognostic factors of PFS and patterns of failure (local recurrence vs metastasis).

Design—Prospective clinical trial.

Animals—25 dogs with locally advanced thyroid carcinomas and no evidence of metastasis.

Procedure—Dogs were treated with 48 Gy during 4 weeks on an alternate-day schedule of 4 Gy/fraction.

Results—Irradiation was safe and effective for treatment of large unresectable thyroid carcinomas. Progression-free survival rates were 80% at 1 year and 72% at 3 years. Time to maximum tumor size reduction ranged from 8 to 22 months. Factors affecting PFS were not found. Twenty-eight percent (7/25) of dogs developed metastasis. Dogs with bilateral tumors had 16 times the risk of developing metastases, compared with dogs with a single tumor. Dogs with no evidence of tumor progression had 15 times less risk of developing metastases. Radiation-induced hypothyroidism was suspected in 2 dogs 13 and 29 months after irradiation.

Conclusions and Clinical Relevance—Irradiation is effective for local control of thyroid tumors, despite their slow regression rate. Results provided evidence that local tumor control affects metastatic outcome in dogs with thyroid carcinomas and is a strong basis for the development of new approaches that include irradiation in the management of dogs with advanced thyroid carcinomas. Improvements in local tumor control alone may be insufficient to improve survival times because of the high risk of metastatic spread before an initial diagnosis is made, which warrants initiation of early systemic treatment. (J Am Vet Med Assoc 2000;216: 1775–1779)

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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)

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To describe radiotherapy outcomes for canine infiltrative lipomas and provide detailed radiotherapy planning data.

ANIMALS

24 dogs from 2000 to 2020.

METHODS

In this retrospective study, dogs received 1 to 3 surgeries prior to conventionally fractionated radiotherapy for gross (18) or microscopic (8) infiltrative lipomas. Dogs received 45 to 51 Gray (Gy) in 15 to 20 daily fractions, with 71% of dogs receiving 48 Gy in daily 3-Gy fractions.

RESULTS

Masses were regionally located as follows: limbs (7), trunk (13), head/neck (4). At analysis, 16/24 dogs were deceased, 5/24 were alive (median follow-up for alive dogs: 1,216 days [range, 741 to 1,870 days]), and 3/24 were lost to follow-up. One living dog had progressive disease 923 days after completing conventionally fractionated radiotherapy and received another surgery. The estimated median overall survival (OS) after completing radiotherapy was 4.8 years (1,760 days; 95% CI, 1,215 to 2,777 days; range, 23 to 3,499 days) for any cause of death, and no patients were reported to have been euthanized or died from their tumor. No statistically significant difference was found for dogs based on gross versus microscopic disease (gross OS, 4.8 years vs microscopic OS, 3.6 years; P = .45). Furthermore, the number of surgeries before radiotherapy did not impact survival (P = .96). The survival difference between females (median OS, 7.6 years; 95% CI, 963 days to not reached) versus males (median OS, 4.6 years; 95% CI, 335 to 2,245 days; P = .05) was statistically significant, although 4/5 living dogs were female.

CLINICAL RELEVANCE

This study demonstrates lengthy survivals with radiotherapy, even with gross disease, for dogs with infiltrative lipomas.

Full access
in Journal of the American Veterinary Medical Association

Objective

To determine the benefits of reducing the interval between surgical cytoreduction and intratumoral administration of cisplatin.

Design

Randomized clinical study.

Animals

70 horses with 89 incompletely resected T2- and T3-stage sarcoids (n = 64) and squamous cell carcinomas (25).

Procedure

Horses were given 4 intratumoral treatments of cisplatin at 2-week intervals. The first treatment was given at the time of, or immediately after, surgical resection for horses treated in accordance with the perioperative protocol (group 1). Horses in group 2 were treated with cisplatin after the skin healed following surgical resection in accordance with the postoperative protocol.

Results

A difference was not found in duration of overall local tumor control between the 2 groups. Patterns of treatment failures and interval to failure differed between the 2 groups. Length of the surgical scar was the only factor that affected prognosis; an increase in length was associated with a poorer prognosis. A detrimental effect of postoperative treatment was only found in tumors with a high tumor proliferative fraction. Local reactions were similar for the 2 treatment groups, and chronic reactions were not observed.

Conclusions and Clinical Relevance

Intratumoral administration of cisplatin is beneficial for treatment of cutaneous tumors in horses. Tumor repopulation during the interval between surgery and intratumoral administration of cisplatin decreases treatment efficacy. These results provide evidence of rapid tumor repopulation following surgical resection without a lag period for tumors with a high proliferation index. When tumor proliferation index is not known, it may be prudent to use the perioperative protocol. (J Am Vet Med Assoc 1999;215:1655–1660)

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in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine effects of glutamine-supplemented and glutamine-free amino acid-based purified diets, compared with a dry expanded diet, on intestinal structure and function in a model that used cats with methotrexate-induced enteritis.

Animals

18 adult specific-pathogen-free cats.

Procedure

12 cats were given intragastric feedings of an amino acid-based purified diet supplemented with glutamine (7% [wt:wt]) or an isonitrogenous amount of glycine and alanine; 6 cats consumed a dry expanded diet. After 21 days, cats received methotrexate (MTX; 11 mg/kg of body weight, IV). Intestinal permeability testing was performed immediately before and 66 hours after MTX administration. Celiotomy was performed 72 hours after MTX administration for aseptic removal of mesenteric lymph nodes, collection of full-thickness intestinal biopsy specimens, determination of intestinal cellular proliferation, and collection of aortic and portal venous blood samples for determination of arteriovenous amino acid concentrations across the intestine.

Results

Administration of MTX was associated with severe enterotoxicosis manifested as diarrhea (8/12 cats), vomiting (12/12), and positive results for bacterial culture of mesenteric lymph nodes (12/12) in cats receiving the purified diets, independent of glutamine supplementation. Diet did not affect villus tip length and villus surface area in the small intestine or cellular proliferation. Administration of MTX was associated with significantly increased intestinal permeability, which was not attenuated by glutamine supplementation.

Conclusions

Feeding of a glutamine-supplemented amino acid-based purified diet was unable to preserve intestinal function in cats with MTX-induced enteritis.

Clinical Relevance

Intestinal morphologic alterations correlate poorly with intestinal function as measured by means of bacterial translocation and intestinal permeability. (Am J Vet Res 1999;60:755-763)

Free access
in American Journal of Veterinary Research

Objective

To determine efficacy of cobalt 60 radiotherapy in dogs with pituitary-dependent hyperadreno-corticism (PDH) that have detectable tumors but no neurologic abnormalities.

Design

Case series.

Animals

6 dogs with PDH that had a detectable pituitary mass on magnetic resonance images.

Procedure

Radiation was delivered in 11 fractions during a 3.5-week period for a total dose of 44 Gy. Clinical signs were evaluated, a urinalysis and ACTH stimulation test were performed, and urine cortisol-to-creatinine ratio and plasma endogenous ACTH concentration were measured before, immediately after, and 1, 3, 6, 9, and 12 months after radiotherapy. Magnetic resonance imaging was repeated 1 year after radiotherapy.

Results

Clinical signs of hyperadrenocorticism resolved in 3 dogs but recurred in 2 of the 3. Clinical condition of 2 dogs improved but did not return to normal. One dog did not improve. Results of ACTH stimulation tests and urine cortisol-to-creatinine ratios correlated with clinical signs. Plasma endogenous ACTH concentration transiently decreased in all 6 dogs. One year after radiotherapy, size of tumors was decreased by 25% in 2 dogs; in the other 4 dogs, tumors could no longer be detected. None of the dogs developed neurologic abnormalities. Adverse effects of radiotherapy were mild.

Clinical Implications

Radiotherapy did not result in adequate control of clinical signs of hyperadrenocorticism in 5 of 6 dogs, but size of pituitary tumors was dramatically reduced. Thus, it may be reasonable to recommend radiotherapy in dogs with PDH that have pituitary tumors for which greatest vertical height is 8 mm or more. (J Am Vet Med Assoc 1998; 212:374-376)

Free access
in Journal of the American Veterinary Medical Association

Summary

Ninety cats were irradiated for treatment of squamous cell carcinoma of the nasal plane. The 1- and 5-year progression-free survival rates were 60.1 ± 5.5% and 10.3 ± 6.2%, respectively. Analysis of progression-free survival times revealed that clinical stage and tumor proliferative fraction (estimated by the use of a proliferating cell nuclear-antigen immunohistochemical method) had significant prognostic value. Conversely, coat color, presence of multiple facial carcinomas, histologic grade, and feline immunodeficiency virus infection status were not found to have prognostic value. Acute radiation reactions were mild and self-limiting. Severe chronic radiation reactions were more frequent in cats infected with feline immunodeficiency virus. Results of the study indicated that cats with squamous cell carcinoma of the nasal plane benefit from radiotherapy and that treatment might be improved by increasing the radiation dose as well as altering the dose-fractionation scheme.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine outcome associated with cutaneous tumors treated via intratumoral chemotherapy with cisplatin and identify risk factors affecting local tumor control and complications in equidae.

Design—Retrospective case series.

Animals—573 equidae with 630 cutaneous tumors.

Procedures—Medical records of horses, mules, donkeys, and ponies with cutaneous tumors treated via intratumoral chemotherapy with cisplatin were analyzed.

Results—549 horses, 13 mules, 8 donkeys, and 3 ponies with 630 histologically confirmed cutaneous tumors were included. Tumors included sarcoids (n = 409), squamous cell carci nomas (151), soft tissue sarcomas (28), cutaneous lymphomas (26), and melanomas (16). Overall cure rate, defined as local control at 4 years, was 93.3%. For all tumor stages combined, cure rates after 1 course of treatment were 96.3% for sarcoids, 96% for lym-phomas, 88% for squamous cell carcinomas, 85% for soft tissue sarcomas, and 81% for melanomas. Treatment protocol, tumor stage, and prior treatment were significant prog nostic factors for tumor control. Treatment efficacy was lower for large tumors, those with gross postoperative residual disease, and those that had been treated previously with other modalities. Treatment was well tolerated. Local reactions were more likely to occur and to be more severe after the third and fourth treatment sessions.

Conclusions and Clinical Relevance—Results confirmed the value of intratumoral chemotherapy with cisplatin for treatment of cutaneous tumors in equidae.The results cannot be extrapolated to other formulations of cisplatin or other protocols that might be used.

Full access
in Journal of the American Veterinary Medical Association

  • 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