Biomedical subjects

S J Withrow

Publications and source records attributed to S J Withrow.

At least 55 records · Page 3Linked to original sources

PubMed1993

Prevalence of nephrotoxicosis associated with a four-hour saline solution diuresis protocol for the administration of cisplatin to dogs with naturally developing neoplasms.

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.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Intra-arterial cisplatin with or without radiation in limb-sparing for canine osteosarcoma.

METHODS: Forty-nine dogs with spontaneously occurring osteosarcoma underwent limb-sparing surgery after preoperative therapy consisting of intra-arterial cisplatin alone or intra-arterial cisplatin in combination with doses of radiation from 20-40 Gy in 10 fractions. All resections were marginal, and the defect was repaired with a cortical allograft. RESULTS: Local tumor control was strongly influenced by the percent necrosis in the excised specimen. Overall, the estimated 1-year local recurrence rate was approximately 32% (by life-table estimate). Dogs with less than 75% necrosis had an estimated 1-year recurrence rate of 65%; those with greater than 75% necrosis had an estimated 1-year recurrence rate of 15% (P = 0.004, by log-rank test). Local recurrence was influenced by the radiation dose. Dogs receiving 28 Gy or less had an estimated 50% 1-year recurrence rate, and those receiving 32 Gy or more had an estimated 8% 1-year recurrence rate (P = 0.03, by log-rank test). Normal host bone more frequently became necrotic at doses of 36 Gy or more. CONCLUSIONS: Intra-arterial cisplatin in combination with moderate doses of radiation (32 Gy) can achieve a high percent tumor necrosis while maintaining host bone viability. Survival was limited by distant metastasis but was lengthened by treatment compared with some earlier findings.

Amputation, Surgical↗

PubMed1993

Evaluation of single-agent chemotherapy for treatment of clinically evident osteosarcoma metastases in dogs: 45 cases (1987-1991).

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).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

The effect of intramedullary polymethylmethacrylate on healing of intercalary cortical allografts in a canine model.

The purpose of this study was to evaluate the effect of intramedullary polymethylmethacrylate (PMMA) bone cement on the healing of intercalary allografts. Thirteen adult beagles had bilateral intercalary femoral allografts implanted. The medullary canal of one randomly assigned allograft in each dog was filled with PMMA. Healing was followed clinically and femora were evaluated radiographically, biomechanically, histologically, and histomorphometrically 9 months after surgery. There was an increased percent of eroded surface at the endosteal area of the center region of grafts containing PMMA and there was an increased percent osteoblast surface in this area in grafts not containing PMMA. There was an increased percent eroded surface at the periosteal area in the center region in grafts not containing PMMA and there was an increased percent osteoblast surface at the periosteal area in the graft adjacent to the host junction in grafts containing PMMA. There was no significant difference between PMMA-treated and untreated allografts in any other parameters measured. The results from this study suggest that, although the pattern of incorporation is altered, intramedullary PMMA does not appear to effect allograft healing adversely.

Animals↗

PubMed1992

Evaluation of a one-hour saline diuresis protocol for administration of cisplatin to dogs.

A study was undertaken to determine the toxic effects of cisplatin, an antineoplastic agent, when administered immediately after a 1-hour saline diuresis. Four treatments with cisplatin (70 mg/m2 of body surface, q 3 wk) were administered IV to 6 healthy dogs over a 20-minute period after 0.9% NaCl (saline) solution was administered IV for 1 hour at a volume of 132 ml (kg)0.75. Each dog vomited at least once within 8 hours after each treatment was administered. Clinical status, body weight, and food consumption were normal throughout the 12-week study for 5 of the 6 dogs. The sixth dog developed acute renal failure and became acutely blind and deaf within 3 days after the fourth treatment with cisplatin. Serum electrolyte, creatinine, and urea nitrogen values remained within established normal limits in all dogs immediately prior to each treatment, and in 5 of 6 dogs evaluated 3 weeks after the final treatment. The serum creatinine value (3.3 mg/dl) obtained from the Beagle euthanatized 2 weeks after the fourth treatment was above established normal values. Despite normalcy for all but 1 of the creatinine values, serum creatinine concentration obtained 3 weeks after the final treatment with cisplatin was significantly (P = 0.0001) higher than pretreatment values. When compared with data from all other evaluation periods, significant decreases in glomerular filtration rate, as determined by exogenous (P less than or equal to 0.0001) and endogenous (P less than or equal to 0.0001) creatinine clearance testing, were identified 3 weeks after the fourth treatment with cisplatin.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗

PubMed1991

Prevalence of nephrotoxicosis associated with a short-term saline solution diuresis protocol for the administration of cisplatin to dogs with malignant tumors: 61 cases (1987-1989).

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.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Toxicoses associated with administration of mitoxantrone to dogs with malignant tumors.

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 less than 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 less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Efficacy of mitoxantrone against various neoplasms in dogs.

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 (greater than 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.

Animals↗

PubMed1991

Percent tumor necrosis as a predictor of treatment response in canine osteosarcoma.

The percent tumor necrosis was determined in 200 dogs with spontaneously occurring osteosarcoma. One hundred dogs had no treatment before amputation or death. One hundred other dogs were treated with either radiation therapy alone (n = 23), intraarterial (IA) cisplatin alone (n = 16), intravenous (IV) cisplatin alone (n = 6), radiation therapy plus IA cisplatin (n = 47), or radiation therapy plus IV cisplatin (n = 8). Eighty-nine of these 100 dogs had their tumors resected 3 weeks after the end of therapy (6 weeks after the initiation of therapy) and replaced with a cortical bone allograft. Dogs with preoperative treatment were evaluated for local tumor control and time to metastasis. The mean percent tumor necrosis in untreated osteosarcoma was 26.8%. The mean percent tumor necrosis for dogs receiving radiation only, IA cisplatin only, and IV cisplatin only was 81.6%, 49.1% and 23.8%, respectively. The mean percent tumor necrosis for dogs receiving radiation therapy plus IA cisplatin or radiation therapy plus IV cisplatin was 83.7% and 78.2%, respectively. There was no significant difference between percent tumor necrosis in untreated osteosarcoma compared with those receiving IV cisplatin, but there was a significant increase in percent tumor necrosis with all other treatments. A mathematic model for the effect of cisplatin and radiation dose was developed using multiple regression analysis. The radiation dose calculated to cause at least 80% tumor necrosis was 42.2 Gy (95% confidence interval [CI], 38.0 to 47.6 Gy) when radiation was given alone and 28.1 Gy (95% CI, 21.3 to 36.6 Gy) when radiation was combined with IA cisplatin. Areas of viable tumor tended to be most frequent adjacent to the articular cartilage and in the joint capsule. Percent tumor necrosis was strongly predictive for local tumor control; 28 of 32 dogs with greater than 80% tumor necrosis had local control, and only eight of 29 dogs with less than 79% tumor necrosis had local control (P = 0.0047). There was no correlation between percent tumor necrosis and time to metastasis.

Animals↗

PubMed1991

Muscle injury following experimental intraoperative irradiation.

The paraaortic region of beagle dogs was irradiated to 15 to 55 Gy intraoperative irradiation, 10 to 47.5 Gy intraoperative irradiation following 50 Gy external beam irradiation in 25 fractions, or 50 to 80 Gy external beam irradiation in 30 fractions. Six MeV electrons were used for intraoperative irradiation, and external beam irradiation was done using photons from a 6 MV linear accelerator. The psoas muscle in the irradiation field was examined histomorphometrically 2 or 5 years after irradiation. The percentage of muscle fibers and capillaries decreased, whereas the percentage of connective tissue increased with increased dose for both intraoperative irradiation only and intraoperative irradiation plus external beam irradiation. The dose causing a 50% decrease in the percentage of muscle fibers was 21.2 Gy and 33.8 Gy at 2 and 5 years, respectively, after intraoperative irradiation alone, and 22.9 Gy and 25.2 Gy at 2 and 5 years, respectively, after intraoperative irradiation combined with 50 Gy external beam irradiation. The ED50 for severe vessel lesions was 19.2 Gy and 25.8 Gy at 2 and 5 years, respectively, after intraoperative irradiation alone and 16.0 Gy and 18.0 Gy at 2 and 5 years, respectively, after intraoperative irradiation combined with 50 Gy external beam irradiation. External beam irradiation alone caused a slight decrease in percentage of muscle fibers with increased dose, and vessel lesions were infrequent or mild. Radiation-induced muscle injury was characterized by loss of muscle fibers, decreased fiber size, severe vessel lesions, hemorrhage, inflammation, coagulation necrosis, and fibrosis. These histopathologic characteristics distinguish this muscle injury from that caused by neurogenic atrophy. These data indicate that radiation-induced muscle injury most likely was caused by injury of the supporting vasculature. The lesions produced were largely a function of the single intraoperative dose rather than the external beam fractionated doses. Furthermore, it appears that 20 to 25 Gy intraoperative irradiation combined with 50 Gy external beam irradiation may be near the maximum tolerated dose by sublumbar musculature and its supporting vasculature.

Animals↗

PubMed1991

Animal illness and human emotion. Cancer.

The practice of veterinary oncology requires that attention be paid to both the medical and emotional needs of patients, clients, and staff members. In order to attend to these needs effectively, practice management goals for diagnosis, treatment, and euthanasia must be clearly established. Common medical and emotional issues pertinent to the practice of veterinary oncology are presented in this chapter. Hands-on information about what to say and what to do while dealing with these issues are detailed. After-care strategies for clients and staff are also included.

Animals↗

PubMed1991

Comparative aspects of osteosarcoma. Dog versus man.

Canine osteosarcoma bears striking resemblance to osteosarcoma in humans. Similarities include the following: male sex predilection, large patient size, 75% or more affecting the appendicular site, metaphyseal location, generally unknown etiology, less than 10% of patients have documented metastasis at presentation, over 90% of tumors show high-grade histology, 75% of tumors show aneuploidy, the metastatic rate is 80% or more with amputation alone, the lung is the most common site of metastasis, and there is improved survival with adjuvant chemotherapy. The major differences are age of onset, with dogs being affected in middle age; greater frequency in the dog, with over 8000 new cases per year; and time to metastasis being faster in the dog than man. Canine osteosarcoma is a readily available and highly comparable spontaneously occurring cancer that should be useful in a better understanding of the same disease in humans.

Age Factors↗

PubMed1991

Cytotoxicity against autologous, allogeneic, and xenogeneic tumor targets by human recombinant interleukin-2-activated lymphocytes from healthy dogs and dogs with lung tumors.

Before dogs with lung tumors were treated by adoptive immunotherapy, the ability of canine blood lymphocytes (PBL) from the peripheral circulation to differentiate in vitro in the presence of human recombinant interleukin-2 (rIL-2) and become tumoricidal was investigated. The PBL from healthy dogs (n = 6) and dogs with lung tumors (n = 5) were grown in culture medium alone, in the presence of rIL-2 to generate lymphokine-activated killer (LAK) cells, or with phytohemagglutinin (PHA) and rIL-2 to generate autologous-stimulated lymphocytes (ASL). After 4 days, cytotoxicity by the ASL, LAK, and PBL was determined in a 4-hour 51chromium-release assay. Target cells in the assay were short-term cultured enzyme digests of autologous (self), allogeneic (genetically different) primary tumors, and Raji, the xenogeneic human lymphoma cell line. The PBL cultured without rIL-2 were not cytotoxic against any tumor. However, when a dog's PBL were activated in vitro, they killed the dog's own tumor, ASL more effectively than LAK cells. Pulmonary adenocarcinomas and an osteosarcoma metastasis to lung were among the autologous tumors assayed. Against an allogeneic canine osteosarcoma, ASL generated from healthy dogs were significantly more cytolytic than LAK from healthy dogs, or than ASL generated from tumor-bearing dogs. Cytotoxicity was greater against allogeneic tumor than against Raji. Lectin-dependent cellular cytotoxicity, tested by including PHA in the assay medium with lymphocytes and Raji cells, by ASL and LAK was greater than cytotoxicity of Raji without PHA. Because ASL were more cytolytic than LAK against all targets in vitro, they may be more beneficial than LAK for immunotherapy of canine tumors.

Adenocarcinoma↗

PubMed1990

Comparison of DNA aneuploidy of primary and metastatic spontaneous canine osteosarcomas.

Spontaneous canine osteosarcomas were analyzed for DNA aneuploidy and percentage of S phase cells using flow cytometry. Forty-eight dogs were studied in which both a primary tumor and subsequent metastases were available. The DNA index distributions for the primary tumors and the metastases were quite similar. However, when individual primary tumors and metastases derived from them were compared, many of the cases had different ploidy values. The tumor cells were also analyzed for percentage of S phase. The diploid metastases had less than 17% S phase cells, whereas the aneuploid metastases had up to 40% S phase cells. There was a direct correlation between the DNA index and the percentage of S phase in the metastases.

Aneuploidy↗

PubMed1990

Radiation-induced osteosarcoma in dogs after external beam or intraoperative radiation therapy.

This report describes radiation-induced osteosarcomas in two groups of dogs. One group was given radiation therapy for spontaneous tumors and the second group of normal adult beagle dogs was given experimental intraoperative radiation therapy. Secondary tumors developed between 1.7 to 5 years after irradiation. Three of 87 spontaneous tumor-bearing dogs or 3.4% of dogs treated for soft tissue sarcomas developed osteosarcoma within the field of irradiation. Twenty-two dogs or 25% of dogs treated for soft tissue sarcomas survived 20 months. This high incidence may be due to the use of fractions in excess of 3.5 Gy. These dogs received 10 fractions in 3 weeks with fractions ranging from 3.5 to 5.0 Gy. Tumor induction may be included in the late effects of irradiation which are worsened by the use of coarse fractionation. There appeared to be a dose relationship for tumors induced after single intraoperative radiation doses combined with fractionated external beam irradiation. Seven of 27 dogs given this treatment and surviving at least 4 years developed osteosarcomas in the field of irradiation. One of 26 dogs given intraoperative radiation alone developed a tumor between 4 and 5 years. The lower incidence after intraoperative radiation alone may have been due to the lower total dose. However, the sequence of a course of fractionated irradiation followed by a large single dose seemed to enhance carcinogenicity.

Animals↗

PubMed1990

Radiotherapy prior to cortical allograft limb sparing in dogs with osteosarcoma: a dose response assay.

Twenty-one dogs with spontaneously occurring appendicular osteosarcoma were given preoperative radiation therapy prior to a limb sparing procedure using a cortical allograft. Radiation doses were randomly assigned, ranged from 36-52 Gy in 4 Gy intervals, and were given in 10 equally-sized fractions on a M, W, F schedule. Seventeen of the 21 dogs underwent the limb sparing procedure approximately 3 weeks after completion of radiation therapy. Local tumor recurrence was documented in 4 of 17 dogs at mean and median times of 5.5 and 5.8 months, respectively, after initiation of radiation therapy. Three of 4 recurrences were in anatomic regions with sparse adjacent soft tissue which precluded wide excision. Complications were significant. Fixation device failure occurred in 9 of 17 dogs and was associated with host bone necrosis, muscle thinning and fibrosis of vessels and nerves in irradiated normal tissue. Incidence of host bone necrosis was directly related to radiation dose (Kendall's statistic, p = 0.005). Metastasis occurred in all 21 dogs. Mean and median times to metastasis in these dogs were 5.1 and 4.0 months, respectively, after initiation of radiation therapy. Local tumor control rates and survival times were higher in dogs developing allograft infection suggesting that infection acted as an immunostimulant. All local failures occurred in dogs that did not develop allograft infection and median survival times for uninfected versus infected dogs were 5 and 11 months, respectively (logrank test, p = 0.029). Increased tumor radiopacity following radiation therapy was significantly related to survival. Median survival in dogs whose tumors were characterized by decreased, unchanged or increased opacity after radiation therapy were 3.5 and 14 months, respectively (logrank test, p = 0.014). Based on the results of our study, radiation therapy can not be recommended as part of limb sparing treatments for patients with osteosarcoma at doses and dose per fraction values similar to those used herein.

Animals↗

PubMed1990

Radiation-induced ocular injury in the dog: a histological study.

Radiation-induced ocular injury secondary to treatment of nasal cancer occurs in humans and animals. Dogs with nasal carcinomas were randomized to receive 36 to 67.5 Gy in fractionated doses given in 4 weeks using a 6 MV linear accelerator. Ophthalmic examinations were performed according to a predetermined protocol and eyes were removed for histologic examination when dogs were euthanatized. The eye in the radiation field exhibited greater injury than the contralateral eye with nasal areas of the globe having more severe lesions than temporal areas. Lesions occurred in all dogs and at all doses. At 1 month or less postirradiation treatment, all dogs had blepharitis, keratoconjunctivitis and corneal epithelial atrophy. Surface lesions persisted in all eyes, becoming less severe and more chronic with time. At 3-6 months postirradiation treatment, degenerative angiopathy of retinal vessels appeared with multifocal retinal hemorrhage and mild diffuse retinal degeneration which affected outer layers first and progressed inwardly with time. At 6 months postirradiation treatment, there were cataracts, fibrosis of retinal vessel walls with loss of vascular smooth muscle, retinal hemorrhage, and mild to moderate retinal degeneration. At 1 year postirradiation treatment, retinal vessels remained sclerotic, retinal hemorrhage was less frequent, and there was moderate retinal degeneration with swelling and loss of ganglion cells. By 2 years or more postirradiation treatment, optic nerve axonal degeneration secondary to retinal changes had appeared. Tapetal and choroidal atrophy were inconsistently seen. Thus, ocular lesions at the doses received developed along a relatively predictable time course and recovery was not seen. Structures of the canine eye appear sufficiently sensitive that even relatively low total doses given in small doses per fraction cause significant long-term injury.

Animals↗

PubMed1990

Management of canine appendicular osteosarcoma.

Canine appendicular osteosarcoma is a highly malignant primary bone cancer that closely resembles the same disease in humans. Although amputation alone usually controls local disease, metastatic cancer is common and is the cause of death or euthanasia in 90% of dogs by 1 year. Cisplatin (+/- doxorubicin) chemotherapy appears to improve survival time in dogs; however, metastatic cancer remains a problem. Pulmonary metastasectomy may prolong survival in carefully selected dogs. Limb-sparing, although involved and potentially fraught with complications, can result in local disease control and a functional, pain-free limb in selected dogs without adversely affecting their survival. Studies are ongoing to improve local disease control with limb-sparing and improve disease-free survival in dogs with appendicular osteosarcoma. In conclusion, dogs with osteosarcoma were previously thought to have a hopeless prognosis, but the outlook is beginning to appear more optimistic. Limb-sparing in dogs is still evolving; however, it is possible in selected cases to optimize survival and preserve limb function.

Animals↗