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  • Author or Editor: Michael W. Nolan x
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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To evaluate potential prognostic indicators for local recurrence, distant metastasis, and survival time in dogs with incompletely excised high-grade soft tissue sarcomas (HGSTSs), as defined by a mitotic index ≥ 9, that underwent definitive-intent radiation treatment (RT; ≥ 48 Gy total dose) with or without adjuvant chemotherapy.

ANIMALS

41 client-owned dogs with HGSTSs treated with surgical resection followed by definitive-intent RT between January 1, 2000, and December 31, 2016.

PROCEDURES

Medical records were reviewed retrospectively, and data were collected. The Kaplan-Meier method was used to evaluate the overall survival time (OST) of dogs and time to progression (TTP) of disease, starting from the first day of RT. The Cox proportional hazards model was used to analyze the impact of results for several variables on OST and TTP.

RESULTS

The median OST was 981 days, with 1-, 3-, and 5-year survival rates of 85%, 43%, and 18%, respectively. The median TTP was not reached; however, the mean TTP was 1,581 days. Ten of the 41 (24%) dogs developed metastasis, and 8 (20%) developed local recurrence. Sixteen of the 41 dogs received chemotherapy. The hazard of disease progression over the study period increased as the mitotic index (hazard ratio [HR], 1.115) or duration of RT (HR, 1.427) increased. The hazard of death over the study period increased as the RT duration (HR, 1.372) or surgical scar length (HR, 1.272) increased.

CONCLUSIONS AND CLINICAL RELEVANCE

Although adjuvant chemotherapy was not associated with improved survival time in dogs of the present study, results indicated that improved OST and TTP could be achieved through strict adherence to the prescribed irradiation schedule and avoidance of unnecessary prolongation of the course of RT.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate outcomes of stereotactic body radiation therapy (SBRT) in cats with injection-site sarcomas (ISS) via assessment of local responses and recurrences, survival times, and complications.

Design—Retrospective case series.

Animals—11 cats with ISS.

Procedures—Medical records of cats that were treated with SBRT for ISS between June 2008 and July 2012 were reviewed; information on patient demographics (age, sex, and breed), oncological histories (including prior treatment and histologic grade), details of SBRT plans (tumor volume, treatment field sizes, and prescription), response to treatment (including toxicoses), progression-free intervals, and survival times were extracted.

Results—Acute radiation-associated toxicoses were infrequent and limited to mild, self-limiting dermatitis and colitis in 2 and 1 of the 11 cats, respectively. No late radiation-associated toxicoses were observed. The objective response rate was 8 of 11 cats; these patients either had a partial or complete response as determined on the basis of CT or physical examination findings. The median progression-free interval was 242 days, and the median overall survival time was 301 days; median follow-up time of censored subjects was 173 days.

Conclusions and Clinical Relevance—SBRT was completed in 3 to 5 days and was well tolerated when used to treat cats with ISS. Measurable tumor responses were achieved in most cats in this study. Stereotactic body radiation therapy provided a means for palliation of ISS; further investigation is required to determine whether SBRT is a valid treatment option for downstaging disease prior to definitive surgery.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To describe clinical outcomes in cats with insulin resistance and acromegaly treated with stereotactic radiosurgery (SRS).

ANIMALS

14 client-owned cats.

PROCEDURES

Medical records of cats with insulin resistance and acromegaly treated with SRS (17 Gy) between August 2013 and November 2019 at a single institution were reviewed. Kaplan-Meier analysis was used to evaluate overall survival time.

RESULTS

Acute adverse effects of SRS included somnolence (n = 2) and alopecia (1). Delayed adverse effects of SRS included unspecified neurologic complications (n = 1; 481 days), seizures (1; 1,541 days), and hypothyroidism (1; 64 days). Exogenous insulin requirements decreased in 10 of the 14 cats, with a median time to lowest insulin dose of 399 days (range, 42 to 879 days). Complete diabetic remission was achieved in 3 cats. The median overall survival time was 741 days (95% CI, 353 to 1,129 days). Six cats were still alive at the end of the study period, with a median follow-up time of 725 days. In 7 of the 8 cats that had died, death was presumptively attributed to acromegaly owing to continued insulin resistance, organ failure, or altered neurologic status.

CLINICAL RELEVANCE

The SRS protocol was well tolerated and associated with survival times similar to those reported previously. Most cats had decreased exogenous insulin requirements after SRS. Latency to an endocrine response was highly variable, emphasizing the need for careful ongoing diabetic monitoring of acromegalic cats after pituitary gland irradiation.

Open access
in American Journal of Veterinary Research