A retrospective study of 44 canine apocrine sweat gland adenocarcinomas

Apocrine sweat gland adenocarcinomas (AACs) are relatively uncommon skin tumors in dogs. Little prognostic or behavioral information has been published for these tumors. In this retrospective study, 44 AACs from diagnostic archives were reexamined and clinical postexcisional follow-ups for 25 of the 44 cases were obtained by a survey. There were 28 out of 44 (65.9%) AACs that invaded the capsule, stroma, or both, 5 of 44 (11.4%) invaded blood vessels and stroma, and 1 out of 25 (4%) had distant metastases. The presence or absence of stromal and vascular invasion was predicted by clinical examination with more than 80% accuracy. Postexcisional median survival of dogs with AACs was 30 mo at the time of survey. Determination of a correlation between histological features and malignant behavior of AACs was compromised by the low number of cases with clinical AAC-related problems; however, it appears that intravascular invasion is an important indicator of potential systemic metastases.

Efficacy of cobalt-60 radiation therapy for the treatment of nasal cavity nonkeratinizing squamous cell carcinoma in the dog

The purposes of this study were to evaluate the efficacy of cobalt-60 radiotherapy in the treatment of nonkeratinizing squamous cell carcinoma of the nasal cavity in dogs and to compare this treatment group to historical controls. Six dogs with histopathologically confirmed nasal cavity nonkeratinizing squamous cell carcinoma were treated with cobalt-60 radiotherapy to a total dose of either 63 Gy or 54 Gy. Overall survival times ranged from 30 days to 330 days, with a median survival time of 165 days. Nasal cavity nonkeratinizing squamous cell carcinoma in the dog is an aggressive tumor that responds poorly to radiotherapy.

Treatment of canine parvoviral enteritis with interferon-omega in a placebo-controlled challenge trial

Canine parvoviral enteritis continues to cause significant morbidity and mortality in dogs worldwide, and efficacious antiviral therapies are lacking. The present trial was aimed at evaluating the therapeutic efficacy of a recombinant feline interferon (type omega) preparation in the treatment of parvoviral enteritis in dogs. A double-blind, placebo-controlled challenge trial was performed in beagle pups (8-9 weeks); clinical signs, body weight, hematologic parameters, and mortality were monitored for a period of 14 days after challenge. Fourteen animals were inoculated with virulent canine parvovirus; 10 animals that developed clinical signs thereby meeting the inclusion criteria were admitted to the treatment phase in two randomly selected groups (placebo and IFN) of equal size. The IFN group received daily intravenous injections of rFeIFN-omega (2.5 MU/kg) for three consecutive days. The placebo group received daily injections of saline without IFN. Both groups of animals received individual supportive treatment consisting of adjusted diet and electrolyte solution. All five dogs in the placebo group developed fulminating enteritis with typical clinical signs and died within 10 days post-inoculation (or 6 days post-treatment). In the IFN-treated group, one animal died on day 2 after the treatment was started, whereas the other four dogs survived the challenge and gradually recovered. Our data confirm that the rFeIFN-omega can exert a significant therapeutic effect on dogs with parvoviral enteritis by improving clinical signs and reducing mortality.

Surgery alone or in combination with radiation therapy for treatment of intracranial meningiomas in dogs: 31 cases (1989-2002)

OBJECTIVE

To compare, for dogs with intracranial meningiomas, survival times for dogs treated with surgical resection followed by radiation therapy with survival times for dogs treated with surgery alone.

DESIGN

Retrospective study.

ANIMALS

31 dogs with intracranial meningiomas.

PROCEDURE

Medical records of dogs with histologic confirmation of an intracranial meningioma were reviewed. For each dog, signalment, clinical signs, tumor location, treatment protocol, and survival time were obtained from the medical record and through follow-up telephone interviews.

RESULTS

Dogs that underwent tumor resection alone and survived > 1 week after surgery had a median survival time of 7 months (range, 0.5 to 22 months). Dogs that underwent tumor resection followed by radiation therapy had a median survival time of 16.5 months (range, 3 to 58 months).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that in dogs with intracranial meningiomas, use of radiation therapy as a supplement to tumor resection can significantly extend life expectancy.

Ultrasonographic and clinicopathologic findings in 21 dogs with intestinal adenocarcinoma

In a retrospective study of 21 dogs with intestinal adenocarcinoma, the signalment, clinical presentation, laboratory findings, ultrasonographic features, treatment, and outcome were reviewed. Anorexia (n = 16), vomiting (n = 15), diarrhea (n = 10), and weight loss (n = 9) were the most common clinical signs reported. Ultrasonographic features that were evaluated included location, length, wall thickness, echogenicity, regional motility, layering, regional lymphadenopathy, and fluid accumulation proximal to the lesion site. All lesions were transmural and associated with complete loss of wall layering. Maximum wall thickening at the lesion site ranged from 7 to 17 mm (median 12 mm, mean 11.9 mm). Most of the dogs had a lesion measuring from 23 to 63 mm in length, (median 40 mm, mean 42 mm). Most intestinal lesions were poorly echogenic and had an irregular lumen. Fluid accumulation proximal to the lesion site was identified in 17 of 21 dogs, and in 13 of 17 dogs the fluid accumulation was considered moderate to severe. Regional lymphadenopathy and/or nodular mesentery/omentum were noted in 12 of 21 dogs. The tumor was located in small intestine for 15 dogs and in the colon for the remaining 6 dogs. Fifteen dogs were treated by surgical resection of the intestinal mass. Their median survival time was 233 days. Only gender appeared to influence survival. Female dogs lived a median of 28 days, whereas male dogs lived a median of 272 days.

Survival and prognostic indicators for dogs with intrahepatic portosystemic shunts: 32 cases (1990-2000)

OBJECTIVE

To determine prognostic indicators for short-term outcome and long-term survival for dogs with intrahepatic portosystemic shunts (IPSS).

STUDY DESIGN

Retrospective study.

ANIMALS

Thirty-two dogs of various breeds.

METHODS

Clinical data extracted from medical records of dogs with IPSS were reviewed and included gender, age at surgery, weight, preoperative packed cell volume (PCV), total plasma protein concentration (TP), albumin (ALB), serum activities of alanine aminotransferase (ALT) and alkaline phosphatase (ALP), preprandial and postprandial bile acid concentrations (pre-BA, post-BA), blood urea nitrogen (BUN), glucose concentration, band neutrophils, per-rectal nuclear scintigraphy shunt fraction, whether an angiogram was performed, shunt location at surgery, whether a partial or complete attenuation of the shunt was performed, rectal temperature at the end of surgery, and duration of surgical procedure. Follow-up was determined from visits to the veterinary teaching hospital or by telephone communications with the owner or referring veterinarian.

RESULTS

Median survival time was 35.68 months, and 1- and 2-year probabilities of survival were 60% and 55%, respectively. Body weight, TP, ALB, and BUN were identified as prognostic indicators for short-term outcome. PCV and TP were identified as prognostic indicators for long-term survival.

CONCLUSIONS

PCV and TP were identified as prognostic indicators for long-term survival, whereas body weight, TP, ALB, and BUN were identified as indicators for short-term outcome in dogs with IPSS. Shunt location at surgery did not have any effect on short-term outcome and long-term survival.

CLINICAL RELEVANCE

Total protein, ALB, BUN, and PCV can be used to determine prognosis of dogs with intrahepatic shunt.

A retrospective study of the incidence and prognostic factors of multicentric lymphoma in dogs (1998-2000)

Sixty-three dogs with multicentric lymphoma were evaluated for risk of diseases. The greatest risk of disease concerned rottweilers as compared to other breeds (odds ratio 6.01 to 0.32-2.75, respectively). A group of 43 dogs under chemotherapy was evaluated for defining factors influencing first remission time duration and survival time. The most important factors for results of chemotherapy were response to therapy, stage and sub-stage of disease according the World Health Organization staging system at the time of diagnosis.

Canine pleural and mediastinal effusions: a retrospective study of 81 cases

Eighty-one cases of canine pleural and/or mediastinal effusions were identified from radiography and ultrasonography records reviewed between 1992 and 2000 at the Queen's Veterinary School Hospital, University of Cambridge. All cases had a follow-up period of at least 12 months. Twenty-eight underlying disease processes were associated with pleural and/or mediastinal effusions. The most common disease was pyothorax (13 cases). Other common diseases identified were idiopathic pericardial effusion, cranial mediastinal mass, idiopathic chylothorax, secondary lung metastases and dilated cardiomyopathy. Approximately one-quarter of all cases recovered completely after initial treatment and one-third of all cases either died during, or were euthanased immediately after, completion of the initial investigations.

Prognosis following surgical excision of canine cutaneous mast cell tumors with histopathologically tumor-free versus nontumor-free margins: a retrospective study of 31 cases

The purpose of this study was to determine if the presence of histopathologically tumor-free versus nontumor-free margins was prognostic for relapse or tumor-related death in dogs following surgical excision of single or multiple cutaneous mast cell tumors confined to the skin without evidence of metastasis to lymph nodes or other noncutaneous sites. Differences in tumor-related death or frequency of relapse between the two groups were not significant. Failure to achieve histopathological tumor-free margins frequently did not lead to local relapse. All tumor-related deaths occurred following local relapse. The lack of statistical support for an association between prognosis and histopathological tumor-free versus nontumor-free margins may be a result of small sample size.

Four fraction palliative radiotherapy for osteosarcoma in 24 dogs

Twenty-four dogs underwent palliative radiotherapy consisting of four 8 gray (Gy) fractions of 60Co radiation on days 0, 7, 14, and 21 at 26 sites for axial (n=11) or appendicular (n=15) osteosarcoma. Response was noted in 92% of sites treated. Seventeen dogs were euthanized due to local or metastatic disease, one dog died of metastatic disease, five dogs died of unrelated causes, and one dog is alive. The four fraction protocol is effective for palliation of clinical signs associated with axial or appendicular osteosarcoma and may result in a higher response rate and longer survival time than three fraction palliative protocols.

Prognostic factors for mortality and thromboembolism in canine immune-mediated hemolytic anemia: a retrospective study of 72 dogs

Medical records of 72 dogs diagnosed with immune-mediated hemolytic anemia (IMHA) were reviewed to find risk factors for the disease, for mortality, and for thromboembolism. Coagulation data of 32 patients were evaluated for mortality or thromboembolism risk factors. Cocker Spaniels were at increased risk for IMHA (P = .012). Timing of vaccination was not associated with development of IMHA. PCV ranged from 5 to 33%, with a mean of 16 +/- 5%. Autoagglutination was present in 42% of the dogs. Platelet counts (n = 60) varied from 3,000 to 793,000/microL (mean, 160,117 +/- 133,571; median, 144,000). Thrombocytopenia (platelet count, <200,000/microL) was present in 70% of the dogs, with severe thrombocytopenia (platelet count, <50,000/microL) being present in 22%. One-step prothrombin time (OSPT) was prolonged in 28% of the dogs tested, and activated partial thromboplastin time (APTT) was prolonged in 47% of the dogs tested. Fibrin(ogen) degradation products (FDPs) were detected in 16 of 28 dogs tested (57%). Disseminated intravascular coagulation (DIC) was diagnosed in 10 of 31 (32%) dogs and was suspected in 8 dogs. Thromboemboli were found in 20 of 25 dogs given postmortem examinations. Mortality rate was 58%. Thrombocytopenia (P = .008) and serum bilirubin concentration of >5 mg/dL (P = .015) were risk factors for mortality, and hypoalbuminemia approached significance (P = .053). Severe thrombocytopenia (P = .046), serum bilirubin concentration of >5 mg/dL (P = .038), and hypoalbuminemia (P = .016) were risk factors for thromboembolism. On evaluation of continuous data, decreased platelet count (P = .057), increased bilirubin (P = .062), and decreased albumin (P = .054) approached significance for decreased survival. A higher risk for thrombosis was found with increased alkaline phosphatase (ALKP) (P = .042), increased bilirubin (P = .047), and decreased albumin (P = .012).

Dorsal laminectomy for caudal cervical spondylomyelopathy: postoperative recovery and long-term follow-up in 20 dogs

OBJECTIVE

To evaluate the postoperative morbidity and long-term outcome of dogs after dorsal laminectomy for caudal cervical spondylomyelopathy (CCSM).

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Twenty dogs with CCSM.

METHODS

Medical records of dogs treated by dorsal laminectomy for CCSM at North Carolina State University and Colorado State University between 1989 and 1999 were reviewed. Information on signalment, onset, progression and duration of clinical signs, diagnostic testing, sites of dorsal laminectomy, postoperative complications, length of hospitalization, and the ambulatory status on discharge was recorded. A minimum follow-up of 7 months was required for inclusion in the study. Neurologic status was graded (0 to 5) preoperatively, 2 days after surgery, and at the time of the study (final score). Improvement or worsening of the neurologic status was assessed by comparison of different scores for each dog. Additional follow-up information was obtained by means of a detailed telephone questionnaire directed at both the owner and referring veterinarian.

RESULTS

Mean duration of clinical signs before surgery was 4.9 months. At admission, 15 dogs were ambulatory and 5 were nonambulatory. Neurologic status worsened in 70% of dogs 2 days after surgery but improved in all but 1 dog over the long term. Mean time to optimal recovery was 3.6 months. Long-term follow-up ranged from 7 months to 9 years (mean +/- SD, 3.2 +/- 2.4 years). Four dogs had confirmed recurrence; 2 other dogs may have had recurrence.

CONCLUSIONS

Dorsal cervical laminectomy is an effective treatment for CCSM in those dogs with dorsal compression or multiple sites of involvement.

CLINICAL RELEVANCE

Although most dogs' neurologic status transiently worsened after surgery, long-term outcome and recurrence rates were comparable to those seen with other surgical techniques for CCSM.

A retrospective study on adverse reactions to canine vaccines in Japan

Adverse reactions to vaccines were examined in 311 canine cases reported to the Ministry of Agriculture, Forestry and Fisheries in Japan during the period of 6 years from April of 1994 to March of 2000, and classified according to their clinical symptoms. There were 27 cases of adverse reactions to rabies virus vaccines. Gastrointestinal symptoms were the most frequently observed (26%), followed by respiratory and/or cardiovascular symptoms (22%) and dermatologic symptoms (11%). There were 284 cases of adverse reactions to non-rabies monovalent vaccines and mixed vaccines. Dermatologic symptoms were the most frequently observed (53%), followed by gastrointestinal symptoms (16%) and respiratory and/or cardiovascular symptoms (14%). Of the total 311 cases, 11 (3.5%) died of adverse reactions to vaccines.

Long-term outcome of 56 dogs with nasal tumours treated with four doses of radiation at intervals of seven days

A retrospective study was undertaken on 56 dogs treated for nasal tumours by megavoltage radiotherapy with a hypofractionated schedule consisting of four doses of 9 Gy given at intervals of seven days. The dogs were followed until they died or were euthanased. The clinical signs had improved in 53 of the 56 dogs by the end of the treatment schedule. Mild acute radiation side effects were observed in the majority of the dogs but late radiation side effects were rare. Kaplan-Meier survival analysis revealed a median survival time after the final dose of radiation of 212 days. The one- and two-year survival rates were 45 per cent and 15 per cent. Fifty of the dogs were euthanased because the initial clinical signs recurred.

Proliferation activity in oral and cutaneous canine melanocytic tumours: correlation with histological parameters, location, and clinical behaviour

A total of 62 canine melanocytic tumours (10 melanocytomas and 52 primary malignant melanomas) were investigated to compare the accuracy of prognosis provided by MIB-1 proliferation index (MIB-1-PI) with classical histological criteria and location. MIB-1-PI was assessed by means of quantitative image analysis of sections immunostained with MIB-1 monoclonal antibody. Tumour location, histological cell type, stromal or lymphatic vessel invasion, maximum tumour thickness, and presence of inflammation or necrosis were recorded for each case. Thirty-eight dogs were submitted to a 1-year follow-up and the clinical outcome of the disease determined. MIB-1-PI in melanocytomas differed significantly from that detected in primary malignant melanomas (P=0.0001). A significant difference in MIB-1-PI was revealed between oral and cutaneous malignant melanomas (P=0.015), and between presence and absence of lymphatic vessel invasion (P=0.05). MIB-1-PI was not correlated with the other parameters. In univariate analysis, only tumour location (oral vs cutaneous), presence of lymphatic vessel invasion, and MIB-1-PI were associated with decreased overall survival (P=0.0001,P=0.0144, and P=0.0489, respectively). In conclusion, the results of our study confirm that the assessment of the MIB-1-PI may be of additional prognostic value for dogs with primary malignant melanomas.

STEALTH liposome-encapsulated cisplatin (SPI-77) versus carboplatin as adjuvant therapy for spontaneously arising osteosarcoma (OSA) in the dog: a randomized multicenter clinical trial

PURPOSE

This trial was designed to compare the efficacy of adjuvant STEALH liposome-encapsulated cisplatin (SPI-77) to "standard-of-care" carboplatin therapy in dogs with osteosarcoma (OSA) in the context of a randomized study design.

METHODS

The study included 40 pet dogs with spontaneously arising OSA which were randomized to receive SPI-77 (350 mg/m(2) i.v. every 3 weeks for four treatments) or carboplatin (300 mg/m(2) i.v. every 3 weeks for four treatments) along with amputation of the affected limb. Median disease-free (DFS) and overall survival (OS) were compared using standard life-table analysis.

RESULTS

The median follow-up was 693 days (range 321-730 days). Of 38 dogs eligible for follow-up, 25 were dead of their disease, 9 were alive and disease-free (8 receiving SPI-77, 1 receiving carboplatin; P=0.02), 2 were free of disease when they were lost to follow-up at 321 and 395 days, and 2 had died of an unrelated disease. The median DFS times for dogs treated with SPI-77 and carboplatin were 156 and 123 days, respectively ( P=0.19). The median OS times for dogs treated with SPI-77 and carboplatin were 333 and 207 days, respectively ( P=0.18).

CONCLUSIONS

While STEALTH liposome encapsulation of cisplatin allowed the safe administration of five times the maximally tolerated dose of free cisplatin to dogs without concurrent hydration protocols, this did not translate into significantly prolonged DFS or OS. However, a larger proportion of dogs receiving SPI-77 enjoyed long-term DFS when compared with dogs receiving carboplatin.

Plasma amino acid concentrations in 36 dogs with histologically confirmed superficial necrolytic dermatitis

Plasma amino acid concentrations were measured in 36 dogs diagnosed with superficial necrolytic dermatitis (SND) via skin biopsy. The median age of the dogs was 10 years, and 27 out of 36 (75%) were male. Twenty-two out of 36 (61%) of the dogs were accounted for by six breeds; West Highland white terriers (six), Shetland sheepdogs (five), cocker spaniels (four), Scottish terriers (three), Lhasa apsos (two) and Border collies (two). The mean concentration (+/- standard deviation) was calculated for each measured plasma amino acid and compared to previously documented concentrations of plasma amino acids measured in dogs with acute and chronic hepatitis. The ratio of branched chain amino acids to aromatic amino acids in the dogs with SND was 2.6, slightly lower than that in normal dogs. The mean plasma amino acid concentrations for dogs with SND were significantly lower than for dogs with acute and chronic hepatitis. A metabolic hepatopathy in which there is increased hepatic catabolism of amino acids is hypothesized to explain the hypoaminoacidaemia seen in SND.

Results of radiation therapy in 19 dogs with cutaneous mast cell tumor and regional lymph node metastasis

The records of 19 dogs with cutaneous mast cell tumor and regional lymph node metastasis (WHO Stage 2) were reviewed to determine the efficacy of radiation therapy in this population. Dogs with grade I (n = 1), grade II (n = 16), and grade III (n = 2) cutaneous mast cell tumor were included in this study. All dogs were treated with a combination of pre-irradiation surgical cytoreduction of the primary tumor, irradiation of the primary tumor and regional lymph node, and oral prednisone. Total radiation dose to the primary tumor and regional lymph node ranged from 48 to 57 Gray (Gy). The medial iliac and hypogastric lymph nodes were irradiated prophylactically in 11 dogs with primary tumor of the pelvic limb and positive ipsilateral popliteal lymph node. Total radiation dose to these lymph nodes ranged from 48 to 57 Gy. For all radiation fields, dose per fraction was 3 Gy, and therapy was administered on a Monday through Friday schedule. Acute and late radiation side effects observed in this study were considered acceptable. The median disease-free survival was 1,240 days (95% confidence interval 256 to 2,391 days). The disease-free survival in dogs with stage 2 mast cell tumor suggests that the combination of surgery, irradiation, and prednisone for the primary tumor along with irradiation of the positive lymph node is effective.

Canine synovial sarcoma: a retrospective assessment of described prognostic criteria in 16 cases (1994-1999)

Pertinent patient data and biopsied tissue from 16 cases of canine synovial sarcoma (SS) were reviewed. Histopathological grade, clinical stage, and tissue immunoreactivity to cytokeratin (broad stain, AE1/AE3 and cytokeratin 7) and vimentin were determined and correlated with survival. Effect of treatment on survival was similarly evaluated. Neither clinical stage nor histopathological grade significantly affected survival patterns. Tissues from all cases stained >30% positively with vimentin, whereas no tissue from any case exhibited cytokeratin immunoreactivity. Dogs receiving surgical tumor excision or amputation had a significantly higher survivability than those receiving no treatment (P<0.02). Treatment aggressiveness may be more appropriate than clinical staging or tumor grading in predicting survival. Reliability of diagnosing and prognosticating canine SS with current immunohistochemistry protocols should be questioned.

Retrospective evaluation of partial parenteral nutrition in dogs and cats

The purpose of this retrospective study was to evaluate the use of partial parenteral nutrition (PPN) in dogs and cats. The medical records of all dogs and cats receiving PPN between 1994 and 1999 were reviewed to determine signalment, reasons for use of PPN, duration of PPN administration, duration of hospitalization, complications, and mortality. Complications were classified as metabolic, mechanical, or septic. One hundred twenty-seven animals (80 dogs and 47 cats) were included in the study, accounting for 443 patient days of PPN. The most common underlying diseases were pancreatitis (n = 41), gastrointestinal disease (n = 33), and hepatic disease (n = 23). Median time of hospitalization before initiation of PPN was 2.8 days (range, 0.2-10.7 days). Median duration of PPN administration was 3.0 days (range, 0.3-8.8 days). Median duration of hospitalization was 7 days (range, 2-20 days). In the 127 animals receiving PPN, 72 complications occurred. These included metabolic (n = 43), mechanical (n = 25), and septic (n = 4) complications. The most common metabolic complication was hyperglycemia (n = 19), followed by lipemia (n = 17) and hyperbilirubinemia (n = 6). Most complications were mild and did not require discontinuation of PPN. Ninety-three (73.2%) of the 127 patients were discharged. All 4 animals with septic complications were discharged from the hospital. The presence, type, and number of complications did not impact the duration of hospitalization or outcome. However, animals that received supplemental enteral nutrition survived more often than those receiving PPN exclusively. Although PPN seems to be a relatively safe method of providing nutritional support, future studies are warranted to determine its efficacy.

[Use of human intravenous immunoglobulin in dogs with primary immune mediated hemolytic anemia]

Immune mediated hemolytic anemia (IMHA) in dogs is a severe disease with a high mortality rate. As human immunoglobulin (HIG) was reported to be beneficial for the treatment of IMHA in dogs we examined the influence of HIG on the course of the disease in our dogs with IMHA. Of 22 dogs with primary IMHA 9 dogs received in addition to routine immunosuppressive therapy HIG at a dose of 0.19 to 0.68 g/kg (median 0.35 g/kg), 13 dogs did not receive HIG (-HIG group). Both groups were similar in terms of age, weight, the presence of autoagglutination, spherocytosis, positive Coombs' test, icterus and pigmenturia. The lowest hematocrit measured during the disease was significantly lower in the +HIG group compared to the -HIG group and dogs in the +HIG group received significantly more transfusions than those of the -HIG group. This is an indication for more severe disease signs of the +HIG group dogs. Although mortality during hospitalization and the time from hospital admission to release or death was not significantly different between the two groups, we interpret this similar course of the IMHA despite more severe signs of the +HIG group dogs as a potential positive effect of the HIG therapy.

Primary thoracic wall tumours of mesenchymal origin in dogs: a retrospective study of 46 cases

Forty-three of the chest wall tumours in 46 dogs were malignant; five had metastases apparent at the time of presentation, five more had metastases discovered intraoperatively. Surgical resection of the tumours was associated with a significantly better outcome than conservative management. The median survival times after surgery for dogs with osteosarcoma was 17 weeks, for dogs with fibrosarcoma it was 26 weeks and for dogs with chondrosarcoma it was 250 weeks. En bloc excision of primary tumours affecting the chest wall was associated with minimal morbidity, but long-term survival was limited by distant metastases, primarily to the lungs. The tumours recurred in only three dogs. Early, radical surgical excision is recommended in the management of tumours of the chest wall. The prognosis depends on the histologic type of tumour and a histological diagnosis is mandatory before excision.

Prognostic significance of a new histologic grading system for canine osteosarcoma

Histologic grade is an important determinant in clinical outcome of human osteosarcoma (OS). In this study, the histologic characteristics of primary and metastatic canine OS were evaluated using a new classification system. Histologic characteristics were classified in 166 primary and 34 metastatic canine OS. Prognostic variables for clinical outcome were determined using multivariate analysis. Most OS were histologically characterized by severe to extreme cellular pleomorphism, a variable number of mitoses, small to moderate amounts of matrix, a high percentage of tumor cells, and minimal to moderate amounts of necrosis. Tumor invasion into vessels was present in 117/152 (71%) tumors, and 12/50 (24%) of the regional lymph nodes had evidence of metastasis. Classification of the 166 tumors resulted in seven (4%) grade 1, 34 (21%) grade II, and 125 (75%) grade III OS. In the multivariate analysis, histologic grade III OS and elevated pretreatment plasma alkaline phosphatase (AP) levels were independent predictors of clinical outcome. Dogs with high-grade tumors and elevated AP should be carefully evaluated for the presence of metastatic disease before starting adjunctive therapy protocols.