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  • Author or Editor: Rodney Straw x
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Summary

Medical records of 15 dogs with infiltrative lipoma, 1 of which had 2 lesions, were reviewed. Median age of affected dogs was 6.0 years, and median weight was 30.5 kg. The ratio of females to males was 4:1. Eight of the dogs were Labrador Retrievers. In 8 dogs, the lesions had previously been excised. There was not any apparent site predilection. Excision was the only treatment in all 15 dogs, and follow-up information was available for all dogs. Two dogs, each of which had 1 tumor, were euthanatized immediately after surgery, because the tumor could not be completely excised. Of the remaining 14 tumors, 5 (36%) recurred. Median time to recurrence for these 5 tumors was 239 days (range, 96 to 487 days). By means of Kaplan-Meier analysis, the percentage of dogs disease free 1 year after surgery was calculated to be 67%.

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in Journal of the American Veterinary Medical Association

Summary:

A study was undertaken to determine the effect chemotherapy had when used to treat 45 dogs with measurable metastatic osteosarcoma. The primary tumor was histologically confirmed as an osteosarcoma in each case. Thirty-nine dogs had the primary tumor surgically removed. Twenty-four of these dogs were treated adjunctively with cisplatin (70 mg/m2 of body surface, IV, q 3 weeks; median 2 doses, range 1 to 6 doses) prior to the onset of metastasis. The remaining 6 dogs from which the primary tumor was not surgically removed were diagnosed as having metastatic osteosarcoma in addition to the primary tumor on initial examination.

The median time from initial examination until the development of metastatic disease was 115 days (range, 27 to 1,199 days). The location of the metastatic disease was lungs (31 dogs), bone (3 dogs), soft tissue (1 dog), and multiple sites including lungs, bone, and soft tissue sites (10 dogs). The metastatic lesions were confirmed by pretreatment biopsy (n = 8) or cytologic evaluation (n = 2) in 10 cases and at necropsy in 27 cases. The remaining 8 cases were diagnosed radiographically as multiple metastatic lesions in the lungs consistent with metastatic osteosarcoma.

The metastatic disease was treated with cisplatin in 31 dogs (70 mg/m2, IV, q 3 weeks; median 2 doses, range 1 to 4 doses), doxorubicin in 11 dogs (30 mg/m2, IV, q 3 weeks; median 2 doses, range 1 to 3 doses), and mitoxantrone in 3 dogs (5 mg/m2, IV, q 3 weeks; median 2 doses, range 1 to 3 doses). Eight dogs that had metastatic disease treated with cisplatin were also given doxorubicin; 2 dogs treated with either doxorubicin or mitoxantrone were treated subsequently with cisplatin. The extent of neoplastic disease was determined immediately before the first dose of chemotherapy, and then every 3 to 6 weeks thereafter unless the dog had signs compatible with progressive disease, in which case, an evaluation was done more frequently. Each dog was treated with one chemotherapeutic agent until the dog developed progressive disease, or until the dog's quality of life diminished to an unacceptable level as determined by the owner or attending veterinarian. One dog treated with doxorubicin achieved partial remission. The duration of the partial remission was 21 days, and the lesion was confirmed to be osteosarcoma on necropsy 159 days after the metastatic disease was diagnosed. The median survival time of the other 44 dogs that did not respond to treatment from the time the metastatic disease was diagnosed was 61 days (range, 14 to 192 days). Cisplatin, doxorubicin, and mitoxantrone chemotherapy appear to be ineffective for the treatment of measurable metastatic osteosarcoma in the dog.

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in Journal of the American Veterinary Medical Association

Summary

Medical records of 25 dogs with histologically low-grade fibrous masses of the maxilla and mandible were reviewed. Most of the dogs had extensive clinical histories and had had previous biopsies of the affected regions, from which specimens were often interpreted as benign fibrous connective tissue. The most common breed represented was Golden Retriever (13/25 dogs, 52%). Skull radiographs were evaluated for 22 dogs, and 16 dogs (72%) had evidence of bone lysis. At admission, none of the dogs had radiographic evidence of pulmonary metastasis. On subsequent examinations and necropsy, prevalence of pulmonary metastasis was 12% (3/25 dogs) and of regional lymph node metastasis, 20% (5/25 dogs). Histologic appearance of all specimens was similar and was characterized by proliferation of fibrous connective tissue, with moderate to low cellularity, that aggressively infiltrated adjacent normal tissue. Treatment modalities varied considerably. Surgical excision in combination with radiation therapy, surgery alone, radiation therapy alone, and radiation therapy used adjunctly with localized hyperthermia prolonged survival times in some dogs. The clinical signs, tumor behavior, and histologic characteristics of these lesions were distinctive from those in previously described oral fibrosarcomas in dogs. Comparatively, these tumors most closely resembled aggressive fibromatoses in human beings in regard to clinical signs, local invasive behavior, and histologic appearance, but differed in the prevalence of metastasis.

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in Journal of the American Veterinary Medical Association

Objective

To determine results of surgery for treatment of soft-tissue sarcomas in dogs and to identify prognostic variables that can be used to predict outcome.

Design

Retrospective case series.

Animals

Dogs with soft-tissue sarcomas that had surgical treatment only.

Procedure

Records were examined for clinically relevant data. Histologic samples were reviewed. Follow-up information was obtained by physical examination or telephone conversations with referring veterinarians or owners.

Results

75 dogs with soft-tissue sarcomas of the trunk and extremities were identified. Median age was 10.6 years. Malignant peripheral nerve sheath tumors were of a significantly lower grade than other tumors. Tumors recurred locally in 11 of 75 (15%) dogs. Evaluation for lack of tumor cells at surgical margins was prognostic for local recurrence. Metastatic disease developed in 13 of 75 (17%) dogs. Tumor mitotic rate was prognostic for development of metastasis. Twenty-five of 75 (33%) dogs died of tumor-related causes. Percentage of tumor necrosis and tumor mitotic rate were prognostic for survival time. Median survival time was 1,416 days.

Clinical Implications

On the basis of a low local recurrence rate and high median survival time, wide excision of tumor margins or radical surgery appeared to be an effective means for managing soft-tissue sarcomas of the trunk and extremities. Analysis of histologic characteristics for prognosis supported use of preoperative biopsy. Surgical margins should be evaluated, and early use of aggressive surgery is indicated in the management of soft-tissue sarcomas in dogs. (J Am Vet Med Assoc 1997;211:1147–1151)

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in Journal of the American Veterinary Medical Association

Summary

Medical records of 23 dogs in which thymoma was diagnosed between Jan 1, 1980 and Dec 31, 1991 were reviewed. All thymomas were located in the cranial mediastinum. Eleven dogs had mega-esophagus, and myasthenia gravis was confirmed in 7 of these 11. One dog developed clinical signs of myasthenia gravis after removal of the thymoma. Concurrent, nonthymic neoplasms were found in 5 dogs, and 2 had hypercalcemia. Three dogs developed third-degree atrioventricular heart block, 1 of which had generalized myositis involving the cardiac muscle.

None of the dogs had evidence of distant metastasis. Histologically, the predominant tumor types were differentiated epithelial type (9/23) and lymphocyte-rich type (6/23). Clear cells (large cells with nonstaining cytoplasm) comprised ≥ 50% of the cell population in tumors from 5 dogs. Mast cells were detected histologically in 85% of the thymomas evaluated. Sixteen dogs were treated, and in 15 of these, surgery was the primary means of treatment. Six of the 9 dogs with megaesophagus that underwent surgery died or were euthanized within 1 week of diagnosis; whereas only 1 of the 4 dogs without megaesophagus that underwent surgery died within 1 week of diagnosis. Two dogs underwent surgery and received adjuvant chemotherapy. One dog died of complications associated with chemotherapy. One dog was treated with chemotherapy alone and survived 14 months. Seven dogs did not undergo treatment; 4 of these were euthanatized immediately after the mass was first discovered.

By means of univariate analysis, age (≤ 8 years old vs > 8 years old), megaesophagus (present vs not present), and histologic type were found to be significantly (P ≤ 0.05) associated with survival time. Only megaesophagus was found to be significantly associated with survival time by multivariate analysis. Dogs with megaesophagus had a Kaplan-Meier median survival time of 4 days. Kaplan-Meier median survival time for dogs without megaesophagus could not be calculated, because most dogs died of causes unrelated to the thymoma and were censored. Kaplan-Meier 1-year survival rate was 83% for dogs without megaesophagus.

Free access
in Journal of the American Veterinary Medical Association

Summary

The study reported here was undertaken to determine the nephrotoxicosis associated with the administration of cisplatin, an antineoplastic agent, to dogs when administered during 6-hour saline solution diuresis. Cisplatin (70 mg/m2 of body surface, iv, every 21 days) was given to 61 dogs with malignant neoplasia with a total of 185 doses in 1 (n = 9 dogs), 2 (n = 26 dogs), 3 (n = 4 dogs), 4 (n = 9 dogs), 5 (n = 2 dogs), and 6 (n = 11 dogs) treatments. The cisplatin was given over a 20-minute period after 0.9% NaCl solution (saline solution) was administered iv for 4 hours at a rate of 18.3 ml/kg of body weight/h. After the cisplatin infusion, saline solution diuresis was continued at the same rate for 2 hours. Before each treatment with cisplatin, dogs were evaluated with at least a physical examination, cbc, determination of serum urea nitrogen concentration, and in most cases, determination of serum creatinine concentration and urine specific gravity. Four of the 61 dogs (6.6%) developed clinically evident renal disease after 2 (1 dog), 3 (2 dogs), and 4 (1 dog) doses of cisplatin were administered. Three of the 4 dogs had preexisting disease of the urinary tract prior to the start of treatment. The survival time in dogs that developed renal disease (median, 145 days; range, 15 to 150 days) was similar to that of all dogs in this study (median, 154 days; range, 30 to 500 days), with 13 dogs still alive at the conclusion of the study. Three of the 4 dogs that developed renal disease were euthanatized because of tumor-related causes and chronic renal failure, whereas the fourth died as a direct result of nephrotoxicosis. Therefore, the 6-hour saline solution diuresis protocol used in this study to administer cisplatin appears to be effective in preventing nephrotoxicosis in dogs with tumors without preexisting urinary tract disease.

Free access
in Journal of the American Veterinary Medical Association

Summary:

We evaluated the development of nephrotoxicosis in 64 dogs with malignant neoplasia given cisplatin during 4-hour saline solution diuresis. Cisplatin (70 mg/m2 of body surface area, iv, q 21 d) was given to 8 dogs once, 22 dogs twice, 9 dogs 3 times, and 25 dogs 4 times. For each treatment, cisplatin was given over a 20-minute period after saline (0.9% NaCl) solution was administered iv for 3 hours at a rate of 25 ml/kg/h. After cisplatin infusion, saline solution diuresis was continued at the same rate for 1 hour. Before each treatment with cisplatin, the dogs were evaluated by conducting a physical examination, cbc, and analysis of serum urea nitrogen and creatinine concentrations, and in most cases, serum phosphorus concentration and urine specific gravity were determined. Exogenous creatinine clearance also was evaluated in 8 dogs prior to 1 (n = 8), 2 (n = 8), 3 (n = 6), and 4 (n = 4) treatments. Five (7.8%) of 64 dogs developed clinically evident renal disease after two (n = 3) and three (n = 2) doses of cisplatin. Two of the 5 dogs had preexisting diseases of the urinary tract prior to the start of treatment. Survival time in dogs that developed renal disease (median, 114 days; range, 26 to 273 days) was similar to that of all dogs in this study (median, 145 days; range, 5 to 586 days), with 30 dogs still alive at the conclusion of the study. Three of the 5 dogs that developed renal disease were alive at the conclusion of the study, 1 died of tumor-related causes, and another died as a direct result of nephrotoxicosis. There was a significant (P < 0.05) decrease in median neutrophil counts and a significant (P < 0.05) increase in median creatinine concentrations prior to the third and fourth treatments, compared with pretreatment values. Therefore, the 4-hour saline solution diuresis protocol used in this study to administer up to 4 doses of cisplatin appeared to be effective in preventing clinically apparent nephrotoxicosis in dogs with tumors and without preexisting urinary tract disease.

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in Journal of the American Veterinary Medical Association

Abstract

Objective

To evaluate efficacy of a controlled-release cisplatin delivery system, used after marginal resection of mammary carcinoma (ie, resection of grossly evident tumor) in mice, to prevent tumor regrowth and metastasis.

Animals

42 female C3H-HeJ mice.

Procedure

Mice were inoculated with mammary carcinoma cells. Between 2 and 6 days later, tumors were marginally resected and mice were assigned to 1 of 3 groups: no treatment (control; n = 14), cisplatin administered intraperitoneally (IP cisplatin; 14), and cisplatin delivered by use of an open-cell polylactic acid system placed within the tumor bed (slow-release cisplatin; 14). Tumor regrowth was measured daily. Mice were euthanatized 14 days after surgery, and complete necropsies were performed.

Results

Tumor regrowth was not detected in the slow-release cisplatin group; however, tumor regrowth was detected in 7 of 14 mice in the IP cisplatin group and 14 of 14 mice in the control group. Median (± SD) number of days to tumor regrowth was 13.5 ± 0.64 and 7.79 ± 0.87 in the IP cisplatin and control groups, respectively. Mice in the IP cisplatin group had significantly delayed tumor regrowth, compared with control mice. Metastases to lungs were detected in 8 of 14 control mice but were not detected in mice in either cisplatin treatment group.

Conclusions and Clinical Relevance

The open-cell polylactic acid with cisplatin delivery system was successful in delaying local tumor regrowth and metastasis in mice with marginally resected mammary carcinoma. Use of a controlled-release cisplatin delivery system may be an effective adjunct treatment following excision of mammary carcinoma in humans and other animals. (Am J Vet Res 1999;60:1347–1351)

Free access
in American Journal of Veterinary Research

Summary

One hundred twenty-six dogs with histologically confirmed, measurable malignant tumors were evaluated in a prospective study to determine the response to the antineoplastic drug mitoxantrone. Ninety-five dogs had been refractory to one or more treatment modalities (surgery, n = 57; chemotherapy other than mitoxantrone, n = 37; radiation, n = 4; whole body hyperthermia, n = 1). The extent of neoplastic disease was determined immediately before each dose of mitoxantrone was administered (1 to 10 doses, 2.5 to 5 mg/m2 of body surface area, iv) 21 days apart. Each dog was treated with mitoxantrone until the dog developed progressive disease or until the dog's quality of life diminished to an unacceptable level as determined by the owner or attending veterinarian.

A partial or complete remission (>50% volume reduction) was obtained in 23% (29/126) of all dogs treated. Tumors in which there was a partial or complete remission included lymphoma (11/32), squamous cell carcinoma (4/9), fibrosarcoma (2/9), thyroid carcinoma (1/10), transitional cell carcinoma (1/6), mammary adenocarcinoma (1/6), hepatocellular carcinoma (1/4), renal adenocarcinoma (1/1), rectal carcinoma (1/1), chondrosarcoma (1/2), oral malignant melanoma (1/12), cutaneous malignant melanoma (1/1), myxosarcoma (1/1), mesothelioma (1/1), and hemangiopericytoma (1/1).

Our results indicated that mitoxantrone induces measurable regression in various malignant tumors in dogs.

Free access
in Journal of the American Veterinary Medical Association

Summary

One hundred twenty-nine dogs with histologically confirmed malignant tumors were used in a prospective study to determine the toxicity of the new dihydroxyquinone derivative of anthracene, mitoxantrone, which was administered iv at 21-day intervals at dosages ranging from 2.5 to 5 mg/m2 body surface area. Each dog was evaluated for signs of toxicosis for 3 weeks after each dose was administered or until the dog died, whichever came first. The number of dogs in each evaluation period were as follows: 1 dose (n = 129), 2 doses (n = 82), 3 doses (n = 43), 4 doses (n = 26), 5 doses (n = 19), 6 doses (n = 9), 7 doses (n = 6), 8 doses (n = 5), 9 doses (n = 3), and 10 doses (n = 1). The most common signs of toxicosis were vomiting, diarrhea, anorexia, and sepsis secondary to myelosuppression. None of the dogs died of complications resulting from mitoxantrone treatment. Dogs with signs of toxicosis during the 21-day interval from administration of the first dose of mitoxantrone were 95 times (P = 0.003) more likely to develop signs of toxicosis during the 21-day interval from the second dose of mitoxantrone. Similarly, dogs that developed signs of toxicosis during the 21-day interval from the administration of the second dose were 34 times (P < 0.001) more likely to develop signs of toxicosis during the 21-day interval from the administration of the third dose. With each 1 mg/m2 increase in mitoxantrone, the odds of developing signs of toxicosis increased by 5.9 fold (P < 0.001). The performance status (modified Karnofsky performance scheme) of each dog was not adversely affected to a significant extent by mitoxantrone-induced toxicosis until the fifth dose (P = 0.0008). Cardiac toxicosis was not detected. Mitoxantrone was also administered iv to 4 clinically normal dogs, at a dosage of 5 mg/m2 of body surface area, a decrease in the neutrophil count was seen, with the nadir occurring on day 10 (mean ± sem: 1,159 ± 253 cells/μl; range, 480 to 1,680 cells/μl). Tumor-bearing dogs did not seem to have the same degree of myelosuppression (mean ± sem, 6,263 ± 1,230 cells/μl; range, 228 to 18,600 cells/μl).

Free access
in Journal of the American Veterinary Medical Association