Efficacy of radiation therapy for incompletely resected grade-III mast cell tumors in dogs: 31 cases (1987-1998)

OBJECTIVE: To determine the efficacy (durations of remission and survival) of an alternating-day radiation protocol for incompletely excised histologic grade-III solitary mast cell tumors (MCTs) in dogs. DESIGN: Retrospective study. ANIMALS: 31 dogs. PROCEDURE: Radiation (52 Gy in an 18-fraction alternating-day protocol) was delivered to an area bordered by margins > or = 3 cm around the surgical scar and to the associated local-regional lymph nodes. Dogs were not given chemotherapeutic agents concurrently or after radiation. Information on signalment, duration of remission, and survival time was obtained from medical records. RESULTS: Median and mean durations of remission were 27.7 and 17.0 months, respectively (range, 1 to 47 months). Median and mean durations of survival were 28 and 20 months, respectively (range, 3 to 52 months). Dogs with tumors located on the skin of the pinna, perineum, and prepuce had a median duration of remission greater than dogs with tumors located at other sites (27.7 and 14.4 months, respectively). Dogs with tumors < or = 3 cm in maximum diameter before surgery survived longer than dogs with tumors > 3 cm (31 and 24 months, respectively). The remission rate was 65% and survival rate was 71% at 1 year after treatment. Sixteen dogs that were euthanatized had complications associated with local-regional tumor progression. Systemic metastases to liver, spleen, intestine, and bone marrow were detected in 1 dog. CONCLUSIONS AND CLINICAL RELEVANCE: Without further treatment, incompletely excised grade-III mast cell tumors have high local-regional recurrence; local-regional treatment with radiation may effectively be used to manage many such tumors.     

Clinical characteristics, treatment, and outcome of dogs with presumed primary hepatic lymphoma: 18 cases (1992-2008)

OBJECTIVE-To determine outcome of dogs with presumed primary hepatic lymphoma treated with various multiagent, doxorubicin-based chemotherapeutic protocols and identify factors associated with prognosis. DESIGN-Retrospective case series. ANIMALS-18 dogs with presumed primary hepatic lymphoma. PROCEDURES-Medical records were reviewed for information on signalment, treatment, and outcome. RESULTS-8 dogs had a complete remission (CR), with a median remission duration of 120 days. Dogs with leukocytosis, neutrophilia, hypoalbuminemia, hyperbilirubinemia, or a combination of hypoalbuminemia and hyperbilirubinemia were less likely to achieve a CR. Overall median survival time (MST) was 63 days (range, 2 to 402 days). In a multivariate analysis, response to treatment and serum albumin concentration were associated with MST. Dogs that did not achieve a CR had a significantly shorter MST than did dogs that did achieve a CR (13 vs 283 days, respectively). Dogs with serum albumin concentration < 2.5 g/dL at the time treatment was initiated had a significantly shorter MST than did dogs with serum albumin concentration within reference limits (10 vs 128 days, respectively). There was also a positive correlation between serum albumin concentration and survival time (r = 0.74). CONCLUSIONS AND CLINICAL RELEVANCE-Results suggested that dogs with primary hepatic lymphoma that underwent chemotherapy had a poor prognosis, with a low response rate. Dogs that responded to treatment had a better prognosis, and dogs with hypoalbuminemia had a poorer prognosis.     

Incidence and prognostic importance of lymph node metastases in dogs with appendicular osteosarcoma: 228 cases (1986-2003)

OBJECTIVE: To determine the incidence of regional lymph node metastasis in dogs with appendicular osteosarcoma and determine whether regional lymph node metastasis was associated with shortened disease-free interval or survival time. DESIGN: Retrospective study. ANIMALS: 228 dogs with appendicular osteosarcoma in which regional lymph nodes were examined histologically at the time of limb amputation. PROCEDURE: Information collected from the medical records included signalment; affected site; initial serum alkaline phosphatase activity; whether treatment involved adjuvant chemotherapy and, if so, chemotherapeutic agents administered and number of treatments; disease-free interval; and survival time. RESULTS: 10 (4.4%) dogs had histologic evidence of regional lymph node metastasis at the time of amputation. Median disease-free interval for dogs without regional lymph node metastasis (238 days; range, 0 to 1,067 days) was significantly longer than median disease-free interval for dogs with regional lymph node metastasis (48 days; range, 2 to 269 days). Median survival time for dogs without lymph node metastasis (318 days; range, 20 to 1,711 days) was significantly longer than median survival time for dogs with lymph node metastasis (59 days; range, 19 to 365 days). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that regional lymph node metastasis is rare in dogs with appendicular osteosarcoma but that dogs with lymph node metastasis have a poorer prognosis than do dogs without.     

Intraoperative radiotherapy of carcinoma of the prostate gland in ten dogs

Ten dogs with carcinoma of the prostate gland were treated with intraoperative orthovoltage radiotherapy (radiation therapy to surgically exposed tumors). Seven dogs had tumor growth confined to the prostate gland and urethra, and 3 dogs had carcinoma of the prostate gland and regional lymph node involvement. Total radiation doses delivered to the prostate gland of 9 dogs and the affected regional lymph nodes of 3 dogs, using orthovoltage x-rays, ranged from 20 to 30 Gy. Carcinoma of the prostate gland of one dog was intraoperatively irradiated to 15 Gy and was then given a boost of 40 Gy, using cobalt-60 teletherapy. Survival time ranged from 41 to 750 days after intraoperative radiotherapy. Median and mean survival times for all dogs were 114 and 196 days, respectively. The median survival time for 7 dogs with localized prostatic carcinoma was 180 days, which was longer, but not significantly longer (P = 0.09), than the median survival time of 80 days in 3 dogs having prostatic carcinoma and metastatic disease. Intraoperative radiotherapy was tolerated well and caused complete response in 5 dogs. However, surgical complications in 2 dogs, which had subtotal lymphadenectomy or prostatic biopsy performed concurrently at the time of irradiation, resulted ultimately in their deaths. The 2 other dogs with metastatic disease and 1 dog without metastatic disease also had poor response to treatment. Our results indicated that intraoperative radiotherapy is an effective treatment for localized prostatic carcinoma in the dog.     

Carcinoma of the apocrine glands of the anal sac in dogs: 113 cases (1985-1995)

OBJECTIVE: To characterize the signalment, clinical signs, biological behavior, and response to treatment of carcinoma of the apocrine glands of the anal sac in dogs. DESIGN: Retrospective study. ANIMALS: 113 dogs with histologically confirmed carcinoma of the apocrine glands of the anal sac. PROCEDURE: Data on signalment, clinical signs, and staging were reviewed and analyzed along with treatment modality for potential association with survival time. RESULTS: Sex distribution was approximately equal (54% female, 46% male). One hundred four dogs underwent treatment consisting of surgery, radiation therapy, chemotherapy, or multimodal treatment. Median survival for treated dogs was 544 days (range, 0 to 1,873 days). Dogs treated with chemotherapy alone had significantly shorter survival (median, 212 days) than those receiving other treatments (median, 584 days). Dogs not treated with surgery had significantly shorter survival (median, 402 days) than those that underwent surgery as part of their treatment (median, 548 days). Dogs with tumors > or = 10 cm2 had significantly shorter survival (median, 292 days) than dogs with tumors < 10 cm2 (median, 584 days). Hypercalcemia was identified in 27% (n = 29) of dogs, and those dogs had significantly shorter survival (median, 256 days), compared with those that were normocalcemic (median, 584 days). Dogs with pulmonary metastasis had significantly shorter survival (median, 219 days) than dogs without evidence of pulmonary metastasis (median, 548 days). CONCLUSIONS AND CLINICAL RELEVANCE: Unlike most previous reports, this study revealed an approximately equal sex distribution, and results suggest a more favorable prognosis.     

Evaluation of some prognostic factors for advanced multicentric lymphosarcoma in the dog: 147 cases (1978-1981)

A total of 147 dogs treated with a combination of chemotherapy procedure (vincristine, L-asparaginase, cyclophosphamide, and methotrexate) were evaluated for response to therapy and the influence of age, sex, clinical stage, and body weight to duration of response. Complete response was achieved in 113 dogs (77%), partial response in 26 dogs (17.7%), and no response in 8 dogs (5.4%). The median survival time for the dogs with complete and partial responses was 265 days. An analysis of factors associated with prognosis revealed that age, clinical stage, and body weight were not associated with response to therapy, whereas sex was. Females had a significantly prolonged remission and survival time (P = 0.0001).     

Prognostic Factors in Dogs with Lymphoma and Associated Hypercalcemia

Lymphoma and hypercalcemia were diagnosed in 37 dogs. Twenty-six of the dogs received chemotherapy. The association between some prognostic factors including clinical stage of disease, illness status, presence of bone marrow involvement, and presence of an anterior mediastinal mass and remission duration and survival time was evaluated. Statistical analysis of the prognostic factors showed that the presence of an anterior mediastinal mass had an adverse effect on remission duration (P less than 0.03). Calcium concentration was not significantly related to any of the prognostic factors evaluated. Dogs that received chemotherapy were more likely to be self-supporting than the dogs that were not treated (P less than 0.005). However, initial illness status was not significantly related to remission duration or survival time in the 26 dogs that were treated. Six dogs (25% of dogs treated) survived longer than 14 months. Five of these dogs were female. Overall mean and median remission times were 10.4 and 6 months, respectively.     

Comparison between L-CHOP and an L-CHOP protocol with interposed treatments of CCNU and MOPP (L-CHOP-CCNU-MOPP) for lymphoma in dogs

An L-CHOP protocol with interposed treatments of CCNU and MOPP (L-CHOP-CCNU-MOPP) was evaluated in 66 dogs with stages III-V lymphoma. Results were compared with a historical group of 71 dogs treated with an L-CHOP protocol. Complete remission (CR) rates (85 and 80%, respectively) did not differ significantly between protocols (P = 0.48). First CR duration for dogs treated with L-CHOP-CCNU-MOPP was significantly longer: median, 317 days; 2-year CR rate, 35% versus median, 298 days; 2-year CR rate, 13%, P = 0.05). For the L-CHOP-CCNU-MOPP protocol, dogs in substage-b had a 4.3 times greater hazard of having a relapse than dogs in substage-a (P = 0.002). Frequency of adverse chemotherapy-associated gastrointestinal effects did not differ between protocols (P = 0.77). Neutropenia (primarily after CCNU) occurred more frequently in dogs treated with L-CHOP-CCNU-MOPP (P < 0.001). In summary, the L-CHOP-CCNU-MOPP protocol showed an improved duration of first CR as compared with an L-CHOP protocol, but the relevance of this finding might be subject to clinical judgement.     

Correlation of DNA ploidy to tumor histologic grade, clinical variables, and survival in dogs with mast cell tumors.

By using flow cytometry, a retrospective analysis of the DNA content of 40 primary canine mast cell tumors and seven lymph nodes that contained metastatic mast cell tumor from 44 dogs of various breed, sex, and age was performed on formalin-fixed, paraffin-embedded samples of the tumors and nodes. These samples were chosen according to the following criteria: samples contained sufficient well-preserved tumor tissue in the paraffin block for processing, sufficient patient history data were available, clean and homogeneous cell suspensions were obtained after processing, and interpretable DNA histograms were produced on analysis. The ploidy data obtained were compared with the histopathologic grade, the anatomical site of occurrence, the clinical stage of the tumors, and the survival of the dogs. Over 70% (29/40) of the mast cell tumors were diploid. Three metastatic mast cell tumors in lymph nodes had the same ploidy status as their corresponding primary tumors. In five dogs, mast cell tumors from multiple sites in each dog displayed similar ploidy status. Of 26 dogs evaluated for survival times, 69% (18/26) had diploid tumors and 31% (8/26) had aneuploid tumors. When numbers of diploid versus aneuploid tumors were compared, no significant difference was found between any two grades, clinical stages, or anatomic sites. A significant difference (P = 0.02) was found, however, between aneuploid and diploid tumors when comparing Stage I and non-Stage I disease. The Kaplan-Meier survival plot indicated a tendency towards an increased survival within the first year in dogs with diploid versus aneuploid tumors (P = 0.06).     

Evaluation of a multidrug chemotherapy protocol with mitoxantrone based maintenance (CHOP-MA) for the treatment of canine lymphoma

The purpose of this study was to evaluate the efficacy of adding mitoxantrone to a cyclophosphamide, doxorubicin, vincristine, l -asparaginase and prednisone containing protocol. Sixty-five dogs with multicentric lymphoma were evaluated for overall remission and survival times. Remission and survival time versus stage, substage, pretreatment hypercalcaemia and pretreatment steroid administration were also evaluated. Overall median remission for dogs with multicentric lymphoma was 302 days and overall median survival was 622 days. Of the dogs with multicentric lymphoma, 23 (35%) received all scheduled mitoxantrone doses. Only median survival versus substage was found to be significant (substage a median survival was 679 days and substage b median survival was 302 days, P = 0.025). Increasing the total combined dose of doxorubicin and mitoxantrone may improve remission times when compared with historical controls, and further studies are needed to determine how best to utilize mitoxantrone in multidrug chemotherapy protocols for canine multicentric lymphoma.     

Postoperative adjuvant treatment of invasive malignant mammary gland tumors in dogs with doxorubicin and docetaxel

BACKGROUND: Treatment outcome after surgery alone is unsatisfactory in dogs with invasive malignant mammary gland tumors. HYPOTHESIS: Adjuvant doxorubicin or docetaxel will improve the treatment outcome in dogs with high-risk malignant mammary gland tumors, and the use of docetaxel will be feasible in affected dogs. ANIMALS: Thirty-one dogs with malignant mammary gland tumors of histologic stages II and III (vascular or lymphatic invasion, regional lymph node metastasis, or distant metastasis) were used. METHODS: A prospective clinical trial in which dogs were treated with surgery alone (n = 19) or also received adjuvant chemotherapy (n = 12) with doxorubicin or docetaxel was conducted. Docetaxel was given as an IV infusion at a dose of 30 mg/m2 preceded by dexamethasone and diphenhydramine administration. RESULTS: The recurrence-free interval ranged from 13 to 2,585 days (median not reached); the median metastasis-free interval and overall survival were 294 days and 370 days, respectively. Dogs treated with chemotherapy had a tendency toward higher long-term local control and survival rates, but there was no significant difference in the recurrence-free interval (P = .17), time to metastasis (P = .71), and overall survival (P = .12). Factors found to influence the time to metastasis and overall survival included lymph node metastasis (P = .009) and tumor fixation to underlying structures (P = .043, time to metastasis), as well as age (P = .018) and histologic stage (P < .001, survival). Mild allergic skin reactions were the most frequently observed complications of docetaxel treatment. CONCLUSIONS AND CLINICAL IMPORTANCE: Chemotherapy did not lead to an improved outcome in this population. Docetaxel treatment was well tolerated. Additional investigations of adjuvant chemotherapy in dogs with high-risk mammary cancer are warranted.     

Comparison of COAP and UW-19 protocols for dogs with multicentric lymphoma

BACKGROUND: Various chemotherapy protocols for treating lymphoma in dogs have been published; however, comparison of protocols from different studies is difficult, especially when evaluating survival time and toxicoses. HYPOTHESIS: The choice of COAP (C, cyclophosphamide; O, vincristine; A, cytosine arabinoside; P, prednisone) and a modified University of Wisconsin 19-week (UW-19) induction protocol has no influence on overall survival times in dogs with lymphoma. ANIMALS: One hundred and one dogs with multicentric lymphoma. METHODS: Retrospective study (2001-2006). Dogs induced with either an 8-week COP-based protocol (C, cyclophosphamide; O, vincristine; and P, prednisone) with maintenance therapy (COAP group) or a 19-week CHOP (C, cyclophosphamide; H, doxorubicin; O, vincristine; and P, prednisone) based protocol (UW-19 group) were compared in terms of the duration of first remission, survival time, toxicoses, and cost. RESULTS: There were 71 dogs in the COAP group and 30 dogs in the UW-19 group. Various protocols were used after the first relapse. The median duration of the first remission for the COAP and UW-19 groups were 94 days (range, 6-356 days) and 174 days (28-438 days), respectively (P < .01). The median survival times for dogs in the COAP and UW-19 groups were 309 days (6-620 days) and 275 days (70-1102+ days), respectively (P = .09). Dogs in the COAP group had a hazard ratio of 1.9 (95% CI 1.1-3.4) for death relative to the UW-19 group (P = .03), after controlling for the confounders (World Health Organization clinical stage, age, sex, use of doxorubicin during reinduction). The severity of neutropenia and gastrointestinal toxicoses were significantly higher in the UW-19 group than in the COAP group (P = .01 and P < .01, respectively). CONCLUSION AND CLINICAL IMPORTANCE: Use of a long-term doxorubicin-containing sequential combination chemotherapy protocol is associated with a decreased risk of relapse and death relative to a non-doxorubicin-containing protocol.     

Retrospective comparison of the efficacy of fluconazole or itraconazole for the treatment of systemic blastomycosis in dogs

Background: Itraconazole is recommended for treatment of blastomycosis in dogs. Some evidence suggests that fluconazole might be less hepatotoxic than itraconazole. Objectives: To compare (1) incidence of clinical remission and death; (2) treatment duration; (3) total drug cost; (4) incidence of relapse; and (5) incidence of increased ALT activities in dogs with blastomycosis treated with fluconazole or itraconazole. Animals: One hundred and forty‐four dogs with systemic blastomycosis treated with itraconazole or fluconazole from 1998 to 2008. Methods: Retrospective case review. Information obtained included signalment, body weight, clinical signs, drug regimen, treatment duration, time to clinical remission, and laboratory results. Results: Neither treatment efficacy between fluconazole (75% remission) and itraconazole (90% remission) nor relapse rate (18% for itraconazole, 22% for fluconazole) was significantly different (P= .13, .75, respectively). Treatment duration was significantly longer for fluconazole (median 183 days) than for itraconazole (138 days; P= .001). Costs for fluconazole (median $1,223) were significantly less than for itraconazole ($3,717; P < .001). Incidence of increased ALT activities was not significantly different between groups (17% [3/18] for fluconazole, 26% [6/23] for itraconazole; P= .71). Conclusions: Fluconazole is associated with survival to clinical remission in 75% of dogs with blastomycosis. Although dogs receiving fluconazole were treated longer, drug costs were one‐third those of itraconazole. Hepatotoxicosis, as estimated by increases in serum ALT activity, can be observed with similar incidence for both drugs.     

Survival in Dogs with Nasal Adenocarcinoma: 64 Cases (1981–1995)

Case records of 64 dogs with nasal adenocarcinoma were reviewed. The effects of age, gender, tumor stage, presence of metastatic lesions, and treatment method on survival time were examined. Surgery groups included rhinotomy (n = 9), transnasal curettage (n = 29), and no surgery (n = 26). Chemotherapy groups included fluorouracil-cyclophosphamide combination therapy (n = 15), mitoxantrone (n = 7), and no chemotherapy (n = 42). Fifty-three dogs received fractionated cobalt 60 radiation therapy. Surgical procedure, chemotherapy group, and stage of primary tumor were not significantly associated with survival time ( P > .05). Dogs that received radiation therapy had a significantly longer median survival time (424 days) than dogs that did not (126 days) ( P = .0001). The presence of either regional lymph node or pulmonary metastasis was associated with significantly shorter median survival time (109 days) when compared to dogs without metastases (393 days) ( P = .0125). When only dogs that had received radiation therapy were considered, neither surgical treatment nor chemotherapy group was associated with significant changes in median survival time. An alternate staging system emphasizing the presence or absence of metastases is proposed. Key words: Chemotherapy; Metastasis; Radiotherapy.     

Comparison of the effects of asparaginase administered subcutaneously versus intramuscularly for treatment of multicentric lymphoma in dogs receiving doxorubicin

OBJECTIVE: To determine the effectiveness and safety of asparaginase administered s.c. versus i.m. for treatment of multicentric lymphoma in dogs receiving doxorubicin. DESIGN: Prospective study. ANIMALS: 49 dogs with multicentric lymphoma. PROCEDURE: Dogs were treated with doxorubicin every 3 weeks, for a total of 5 treatments, and were given 3 weekly treatments of asparaginase, s.c. or i.m. Using high-performance liquid chromatography, mean plasma asparagine, aspartic acid, glutamine, and glutamic acid concentrations were determined in dogs before and during treatment with asparaginase (10,000 U/m2 of body surface area, once a week for 3 weeks). Asparaginase was administered s.c. in 23 dogs and i.m. in 26 dogs. Variables evaluated included time to response to chemotherapy, remission and survival times, and clinical and serum biochemical indicators of toxicoses. RESULTS: Using the World Health Organization's staging system for lymphoma, 30 dogs were in clinical stage III and 19 were in clinical stage IV. One week after asparaginase treatment, plasma asparagine concentrations were low and plasma aspartic acid, glutamine, and glutamic acid concentrations were high. Differences in plasma amino acid concentrations were not found between s.c. and i.m. groups. For dogs in clinical stage IV, i.m. administration of asparaginase significantly decreased the number of days to complete remission, compared with s.c. administration (8 vs 17 days, respectively). For dogs in clinical stage III, i.m. administration favorably increased the duration of first remission (191 vs 103 days) and survival time (289 vs 209 days). Overall, dogs treated i.m. had a faster response to chemotherapy (9 vs 15 days), a longer remission (191 vs 109 days), and a longer survival time (286 vs 198 days), compared with all dogs treated s.c. Asparaginase toxicoses were not observed regardless of the route of administration. CLINICAL IMPLICATIONS: For dogs with multicentric lymphoma that are receiving doxorubicin, i.m. treatment with asparaginase is more effective than s.c. treatment.     

Response rates and survival times for cats with lymphoma treated with the University of Wisconsin-Madison chemotherapy protocol: 38 cases (1996-2003)

OBJECTIVE: To determine response rates and survival times for cats with lymphoma treated with the University of Wisconsin-Madison chemotherapy protocol. DESIGN: Retrospective study. ANIMALS: 38 cats with lymphoma. PROCEDURE: Medical records were reviewed, and information on age, sex, breed, FeLV and FIV infection status, anatomic form, clinical stage, and survival time was obtained. Immunophenotyping was not performed. RESULTS: Mean +/- SD age of the cats was 10.9 +/- 4.4 years. Overall median survival time was 210 days (interquartile range, 90 to 657 days), and overall duration of first remission was 156 days (interquartile range, 87 to 316 days). Age, sex, anatomic form, and clinical stage were not significantly associated with duration of first remission or survival time. Eighteen of the 38 (47%) cats had complete remission, 14 (37%) had partial remission, and 6 (16%) had no response. Duration of first remission was significantly longer for cats with complete remission (654 days) than for cats with partial remission (114 days). Median survival time for cats with complete remission (654 days) was significantly longer than median survival time for cats with partial remission (122 days) and for cats with no response (11 days). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that a high percentage of cats with lymphoma will respond to treatment with the University of Wisconsin-Madison chemotherapy protocol. Age, sex, anatomic form, and clinical stage were not significantly associated with duration of first response or survival time, but initial response to treatment was.     

Evaluation of Single-Agent Mitoxantrone as Chemotherapy for Relapsing Canine Lymphoma

Many chemotherapeutic regimens will induce remission in dogs with lymphoma, but almost all dogs suffer relapse. Mitoxantrone was selected for evaluation as single-agent chemotherapy for relapsing canine lymphoma based on its use in humans undergoing salvage chemotherapy for non-Hodgkin's lymphoma and its tumoricidal effect against canine lymphoma. Dogs entered into study had multicentric lymphoma, and all had been treated solely with a standard combination chemotherapy protocol. At 1st relapse, all dogs were again staged and underwent lymph node biopsy. Mitoxantrone was administered IV at 6 mg/m² every 21 days. Dogs were evaluated for lymphadenopathy before each dose of mitoxantrone. Fifteen dogs were entered into study. The average age (±SEM) of the dogs studied was 7.7 ± 0.91 years, and most dogs were large (mean ± SEM weight, 24.44 ± 2.15 kg). Twelve dogs (80%) had B-cell lymphoma, and 3 had T-cell lymphoma. Dogs were staged IV (n = 12) or V (n = 3). The median duration of chemotherapy before entry into the study was 98 days. Overall median duration of response after mitoxantrone chemotherapy was 21 days. Complete responses were attained in 7 of 15 dogs (47%) with a median response duration of 84 days. Nine of 15 (60%) dogs attained a complete remission with additional chemotherapy after failing mitoxantrone chemotherapy. Mild toxicities were observed after mitoxantrone administration. No adverse reactions were observed during mitoxantrone infusions. The results of this study demonstrate that mitoxantrone, as a single agent, has limited value for dogs with lymphoma at 1st relapse after conventional multidrug chemotherapy.     

Efficacy of Combination Chemotherapy for Treatment of Gastrointestinal Lymphoma in Dogs

Background: Chemotherapy for multicentric canine lymphoma has favorable results. The gastrointestinal (GI) tract is the most common extranodal site of canine lymphoma, but there have been no prospective studies to determine outcome when dogs with GI lymphoma are treated with chemotherapy.
Hypothesis: Treatment with a multiagent chemotherapy protocol is associated with a poor outcome in dogs with GI lymphoma.
Animals: Eighteen dogs with histologically confirmed GI lymphoma.
Methods: Prospective clinical trial in which dogs with GI lymphoma were treated with a 20-week combination chemotherapy protocol consisting of induction and consolidation phases.
Results: Thirteen dogs had primary GI lymphoma and 5 had multicentric lymphoma with GI involvement. The majority of the lymphomas (63%) were of T-cell origin. Overall remission rate was 56%; 9 dogs achieved a complete remission for a median of 86 days (range, 22–420 days) and 1 dog achieved a partial remission for 26 days. Overall median survival time was 77 days (range, 6–700 days). Dogs that failed to achieve a remission (10 versus 117 days; P = .002) or had diarrhea at initial presentation (70 versus 700 days; P < .001) had shorter survival times.
Conclusion and Clinical Importance: The response and survival of dogs with GI lymphoma treated with multiagent chemotherapy is poor but long-term survival is possible.     

Analysis of Factors Affecting Survival in Dogs With Aortic Body Tumors

OBJECTIVE: To evaluate the effect of perioperative and operative variables on survival time in dogs with aortic body tumors. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Twenty-four client-owned dogs with histologically confirmed aortic body tumor. METHODS: Seventy-eight patient records of dogs seen at the University of Illinois Veterinary Teaching Hospital between 1989 and 1999 with a diagnosis of a heart-base mass were reviewed. Dogs without histologic conformation of an aortic body tumor were excluded. Age; sex; breed; the presence of pleural effusion, pericardial effusion, or abdominal effusion; evidence of cardiac arrhythmias; evidence of distant metastasis; treatment with pericardectomy; treatment with chemotherapy; and time from diagnosis until euthanasia or death were recorded on a spreadsheet. Cox proportional-hazard ratios were used to calculate the relationship of risk variables to survival time. Median survival time was determined using life-table analysis. RESULTS: Twenty-four dogs met the criteria for inclusion in the study. The median age of dogs with aortic body tumors was 9 years. All dogs had a surgical biopsy performed. Fourteen dogs had a pericardectomy at the time of the biopsy procedure. Of all factors analyzed, only treatment with pericardectomy had a significant influence on survival (P =.0029). Dogs that had pericardectomy survived longer (median survival, 730 days; range, 1-1,621 days) compared with dogs that did not have pericardectomy (median survival, 42 days; range, 1-180 days). This finding was independent of the presence or absence of pericardial effusion at the time of surgery. CLINICAL RELEVANCE: Dogs that are diagnosed with aortic body tumors may benefit from a pericardectomy at the time of surgical biopsy.     

Prednisone and Vinblastine Chemotherapy for Canine Mast Cell Tumor—41 Cases (1992–1997)

Forty-one dogs with mast cell tumors (MCTs) were treated with oral prednisone and injectable vinblastine (VBL), both in the adjuvant setting (23 dogs) and in dogs with gross disease (18 dogs). Adverse effects were noted in 20% (8/41) of the patients, usually after the 1st dose of VBL. Adverse effects were considered mild in 6, and severe, necessitating treatment discontinuation, in 2 (5%). Overall response rate in the evaluable dogs with gross disease was 47% (7/15), consisting of 5 complete responses and 2 partial responses. Median response duration was 154 days (24 to >645 days). As adjuvant therapy to incomplete surgical resection, prednisone and VBL conferred a 57% 1- and 2-year disease-free rate. Median survival time (MST) for the entire patient population was not reached with a median follow-up of 573 days; however, the MST for dogs with grade III MCT was 331 days, with 45% of dogs alive at 1 and 2 years. This is an apparent improvement over historical survival data employing surgery alone. Upon univariate analysis, significant prognostic factors (P < .05) for survival included presence of a locally recurrent tumor, presence of gross disease, argyrophilic nucleolar organizer region frequency, lymph node status, histologic grade, previous chemotherapy, and ulceration of the tumor. Similar criteria were significant when analyzed for time to treatment failure. Response to therapy was also predictive of survival in the gross disease group. Upon multivariate analysis, histologic grade (P = .012) and presence of a locally recurrent tumor (P < .001) were significant factors for survival.