Phase I clinical evaluation of carboplatin in tumor-bearing cats: a Veterinary Cooperative Oncology Group study

BACKGROUND: The dosage of carboplatin in cats has been reported anecdotally and experimentally in non-tumor-bearing cats, but the dosage for carboplatin treatment in tumor-bearing cats has yet to be defined in a prospective clinical trial. PURPOSE: To determine the maximally tolerated dose (MTD) and dose-limiting toxicosis (DLT) of carboplatin in tumor-bearing cats. CATS: Fifty-nine cats with measurable solid tumors. METHODS: The starting dose of carboplatin was 160 mg/m(2) of body surface area IV. Doses were increased by 20 mg/m(2) in cohorts of 3-14 cats until the MTD was reached. RESULTS: The 59 cats entered into this multi-institutional phase I study received 1 or more doses of carboplatin at various dosages and were evaluated for toxicity, response to treatment, or both. The MTD was 240 mg/m(2) and neutropenia was the DLT. For the 1st cycle of treatment in 44 cats evaluated for neutropenia, 6 episodes of grade 3 or greater neutropenia occurred on days 7 (n=1), 14 (n=4), and 21 (n=1). There was no evidence of drug-induced nephrotoxicosis or pulmonary edema. Preliminary evidence of antitumor activity was observed in 7 of 59 (11.9%; 95% CI, 5.6-22.8%) cats evaluated for response to treatment. There was 1 complete response (cutaneous hemangiosarcoma) and 6 partial responses (4 injection site sarcomas, 1 oral squamous cell carcinoma, 1 lymphoma). Responses were of short duration (median, 42 days; range, 7-168 days). CONCLUSIONS AND CLINICAL IMPORTANCE: The dose of carboplatin recommended to treat tumor-bearing cats is 240 mg/m(2) IV every 3-4 weeks.     

Hematological toxicity and therapeutic efficacy of lomustine in 20 tumor-bearing cats: critical assessment of a practical dosing regimen

Twenty cats with spontaneously arising tumors received oral lomustine at a dose range of 32 to 59 mg/m2 every 21 days. Due to biohazard concerns associated with lomustine capsule reformulation, a standardized 10-mg capsule dosage was used for all cats regardless of body weight. Severe hematological toxicity was infrequent, with the incidence of either grade III or IV neutropenia and thrombocytopenia being 4.1% and 1.0%, respectively. Cats receiving higher cumulative doses of lomustine trended toward a greater likelihood for progressive neutropenia (P=0.07). Two cats with lymphoma, two cats with fibrosarcoma, and one cat with multiple myeloma achieved a measurable partial response to lomustine therapy. Cats treated with higher dosages of lomustine trended toward statistically significant higher response rates (P=0.07).     

Combined Gemcitabine and Carboplatin Therapy for Carcinomas in Dogs

Background: Response and adverse reactions to combined gemcitabine (GEM) and carboplatin (CARBO) therapy in dogs with carcinomas are not documented.
Hypothesis: GEM and CARBO are safe for the treatment of dogs with carcinomas.
Animals: Thirty-seven dogs with histologically or cytologically confirmed carcinomas.
Methods: Prospective clinical trial. Dogs were treated with GEM (2 mg/kg, 20–30-minute infusion IV) on Days 1 and 8 and 4 hours later, CARBO (10 mg/kg IV) on Day 1. The cycle was repeated on Day 22.
Results: Thirty-seven dogs (29 with measurable tumor) received a median of 2 cycles (range 0.5–6) for a total of 101 cycles administered. Twelve dogs (32%) developed neutropenia (3 Grade 3, and 5 Grade 4) and 9 (24%) thrombocytopenia (2 Grade 3, and 1 Grade 4). Dogs >20 kg were twice as likely to develop thrombocytopenia ( P = .023). Twenty-seven dogs (73%) had evidence of gastrointestinal (GI) toxicosis, but most signs were of mild to moderate severity and self-limiting. One dog died of treatment-related complications. Overall tumor response rate was 13%. One dog with metastatic prostatic carcinoma achieved a complete remission and 1 dog with intestinal adenocarcinoma and 1 with tonsillar squamous cell carcinoma achieved partial remission. Twelve dogs achieved stable disease for a median of 72 days.
Conclusion and Clinical Importance: GEM and CARBO combination causes mild to moderate hematologic and GI toxicosis in dogs with carcinoma. Response rate in this study was modest, and optimization of dosing of this combination is required.     

Adverse Effects of Concurrent Carboplatin Chemotherapy and Radiation Therapy in Dogs

Background: Concurrent chemo- and radiotherapy improves outcome of certain human neoplasms but with increased signs of toxicity. Reports on adverse effects of concurrent chemo- and radiotherapy in the veterinary literature are scant.
Objective: To report adverse hematologic and gastrointestinal effects of combined carboplatin and radiation therapy in dogs.
Animals: Client-owned dogs with spontaneously occurring neoplasia.
Methods: Retrospective case study. Medical records of 65 dogs were reviewed. Criteria for inclusion were administration of radiation according to 1 of 3 fractionation schemes (19 × 3, 16 × 3, or 12 × 4 Gy) and administration of at least 1 concurrent carboplatin treatment at a dosage of 200–300 mg/m². Dog and treatment-related variables were analyzed for association with signs of intoxication.
Results: Median carboplatin dosage was 200 mg/m² (range, 200–250 mg/m²). Twelve of 58 dogs (21%) developed grade 3 or 4 neutropenia. Eleven of 56 dogs (20%) developed grade 3 or 4 thrombocytopenia. Six of 62 dogs (10%) developed grade 3, 4, or 5 gastrointestinal toxicosis. Analysis of association of dog and treatment-related variables with signs of intoxication was hampered by the small numbers of dogs in individual groups, and no statistically significant associations were found.
Conclusions and Clinical Importance: Combined modality therapy resulted in myelosuppression and gastrointestinal toxicosis. Future studies are needed to determine whether the potential benefit of combined modality therapy outweighs the risk of decreasing chemotherapy and radiation treatment intensity.     

UNEXPECTED TOXICITY FOLLOWING USE OF GEMCITABINE AS A RADIOSENSITIZER IN HEAD AND NECK CARCINOMAS: A VETERINARY RADIATION THERAPY ONCOLOGY GROUP PILOT STUDY

Gemcitabine (2',2'-difluorodeoxycytidine) was given intravenously twice weekly to 10 cats with oral squamous cell carcinoma and 15 dogs with nasal carcinoma undergoing radiotherapy as a radiosensitizing agent. The average total radiation dose was 50 Gy for dogs and 54 Gy for cats given Monday-Friday (planned dose of 54 and 57 Gy, respectively). Dogs received an average of five doses of gemcitabine beginning at 50 mg/m2, and cats received an average of five doses of gemcitabine beginning at 25 mg/m2. Twelve of 15 dogs and five of 10 cats required chemotherapy dose reduction or postponement because of hematologic or normal tissue toxicity. The results herein do not support the use of gemcitabine at the studied dose and schedule, as significant hematologic and local tissue toxicity was observed in the studied patients. Pharmacokinetic data are necessary to best define the efficacy and optimal dose and schedule of gemcitabine in combination with traditional radiotherapy.     

Evaluation of a multi‐agent chemotherapy protocol combining dexamethasone,melphalan, actinomycin D,and cytarabine for the treatment of resistant canine non‐Hodgkin high‐grade lymphomas: a single centre's experience

The DMAC protocol (dexamethasone, melphalan, actinomycin‐D, cytarabine) has been evaluated in American studies for the treatment of relapsed canine lymphoma, comparing similarly to other rescue protocols. The aim of this study was to evaluate efficacy and toxicity of DMAC, in a larger UK cohort of resistant canine lymphomas. Medical records of dogs with resistant non‐Hodgkin high‐grade lymphomas that received DMAC as a rescue protocol were reviewed from 2007 to 2017. Response, time from initiation to discontinuation (TTD) and toxicity (Veterinary Cooperative Oncology Group criteria) were assessed. One hundred dogs were included; 86 received CEOP (modified CHOP including epirubicin) as first‐line treatment. Thirty‐five dogs (35%) responded: 21 complete responders (CRs) and 14 partial responders (PRs). Responders had significantly longer TTD (P < 0.001) compared with non‐responders: 62 days (range 28‐952) for CR vs 32 days (range 20‐70) for PR. Six CR received more than six cycles of DMAC (range 7‐36 cycles) and experienced a longer TTD (median 508, range 126‐952 days). Thrombocytopenia occurred in 45% (24 grade 1‐2, 21 grade 3‐4) and neutropenia in 36% of cases (29 grade 1‐2, 7 grade 3‐4). Gastrointestinal toxicity occurred in 42% of dogs (40 grade 1‐2, 2 grade 3‐4). Owing to chemotherapy toxicity, treatment was discontinued in five, and hospitalization required in six cases. In this study, response to DMAC was lower and of generally shorter duration than previously reported. Toxicity was high, but infrequently led to hospitalization or discontinuation of treatment.     

Intravenous administration of docetaxel to cats with cancer

Background: The safety of IV administration of docetaxel to cats with cancer has not been reported. Objectives: Document adverse effects of IV administration of docetaxel to cats. Animals: Twenty‐one client‐owned cats with any confirmed malignancy. Methods: Cats received up to 5 docetaxel treatments, administered IV every 3 weeks. The initial dosage was 1.0 mg/kg, and dosages were increased by increments of 0.25 mg/kg in cohorts of 3 cats. Adverse events were determined by a CBC at days 7 and 21, serum chemistry and urine specific gravity at day 21, and medical histories provided by the owners. Results: Cats received docetaxel dosages ranging from 1.0 to 2.5 mg/kg, for a median of 2 treatments. Dose‐limiting toxicoses included fever, neutropenia, and vomiting, seen in 2 of the 4 cats treated at 2.5 mg/kg. Hypersensitivity reactions were infrequent (4 of the 21 cats) and mild. The maximum tolerated dosage was 2.25 mg/kg. Conclusions and Clinical Importance: Docetaxel can be administered IV to cats with a low incidence of adverse effects.     

A dexamethasone,melphalan, actinomycin‐D and cytarabine chemotherapy protocol as a rescue treatment for feline lymphoma

Nineteen cats with relapsed high‐grade/large‐cell lymphoma were treated with dexamethasone, melphalan, actinomycin‐D and cytarabine (DMAC). All cats had received Cyclophosphamide, Vincristine, Prednisolone (COP) as first‐line chemotherapy and most cats had received at least 2 prior rescue agents with 14 of 19 having received both epirubicin and lomustine. Five cats (26%) exhibited a response (defined as an improvement or resolution of tumour‐associated clinical signs/tumour volume, or complete/partial response) to chemotherapy though no patients received more than 2 cycles of DMAC. Most cats tolerated the protocol well though 3 patients exhibited Veterinary Cooperative Oncology Group (VCOG) grade 4 neutropenia and 1 patient exhibited grade 4 thrombocytopenia. The median progression‐free survival and overall survival from starting DMAC were 14 and 17 days respectively. There is still an unmet need for successful rescue chemotherapy protocol for cats with relapsed lymphoma. [Correction added on 02 November 2017, after first online publication: The expansion for the term DMAC was previously incorrect and has been corrected in this current version.]     

Adjuvant carboplatin and gemcitabine combination chemotherapy postamputation in canine appendicular osteosarcoma

Background: Appendicular osteosarcoma (OSA), the most common bone tumor in dogs, is typically treated by amputation and adjuvant chemotherapy. Despite numerous efforts, the median survival time (MST) for dogs receiving a platinum compound, doxorubicin, or a combination of these remains at 8–12 months. Evidence from studies in mice suggests that gemcitabine has activity against OSA in vivo. Our preliminary work demonstrated that the addition of low‐dosage (10 mM) gemcitabine to carboplatin resulted in synergistic inhibition of OSA cell viability in vitro. Objective: The purpose of the following study was to determine whether the addition of low‐dosage (2 mg/kg) gemcitabine to carboplatin chemotherapy in dogs with OSA after amputation would improve MST over carboplatin monotherapy. Animals: Fifty dogs with histologically confirmed appendicular OSA. Methods: Dogs were treated prospectively with amputation and up to 4 dosages of carboplatin and gemcitabine in combination every 3 weeks. Results: The chemotherapeutic regimen was well tolerated with only 5 episodes of grade 3 or 4 hematologic toxicity. The median disease‐free interval (DFI) was 203 days and the MST was 279 for all dogs in this study. The 1‐ and 2‐year survival rates were 29.5 and 11.3%, respectively. Dogs with proximal humeral OSA had a shorter median DFI (P= .04) compared with dogs with OSA in other locations. Conclusions and Clinical Importance: These results are comparable to those reported for carboplatin monotherapy indicating that the addition of gemcitabine to carboplatin in dogs with appendicular OSA does not appear to improve outcome.     

Toxicity and efficacy of a novel doxorubicin and carboplatin chemotherapy protocol for the treatment of canine appendicular osteosarcoma following limb amputation

Objective To evaluate the safety and efficacy of a novel doxorubicin and carboplatin chemotherapy protocol for the treatment of dogs with appendicular osteosarcoma following limb amputation. Design Retrospective study. Procedure Dogs diagnosed with appendicular osteosarcoma, with no evidence of metastatic disease, treated with amputation and adjuvant chemotherapy consisting of two doses of doxorubicin given 14 days apart, followed by four doses of carboplatin at 3‐weekly intervals between September 2003 and December 2009 were identified from the medical records of Perth Veterinary Oncology. Haematological and gastrointestinal toxicities were assessed based on information in the medical records and recorded complete blood count results. The efficacy of the protocol was assessed by determining the median disease‐free interval (DFI) and overall survival time (OST) using the Kaplan‐Meier product‐limit method. Results In total, 33 dogs met the inclusion criteria. The median DFI was 231.5 days and the median OST was 247 days. With regard to haematological toxicity, 56% of dogs had a grade 1–2 neutropenia recorded as their highest marrow toxicity and 9% of dogs experienced a grade 3–4 neutropenia, all subsequent to doxorubicin administration. The highest gastrointestinal toxicity was grade 1–2 in 15 dogs (47%) and 5 dogs (16%) experienced grade 3–4 gastrointestinal toxicity. Conclusion This chemotherapy protocol did not result in a longer time to disease recurrence or OST in this population of dogs. Dual‐agent protocols have failed to improve survival times and therefore we conclude that a single‐agent protocol using carboplatin may be equally effective with less toxicity.     

A phase II clinical trial of vinorelbine in dogs with cutaneous mast cell tumors

Background: Few effective drugs are available to treat dogs with locally aggressive or metastatic mast cell disease.
Hypothesis: Vinorelbine, a semisynthetic derivative of vinblastine, is an effective drug for the treatment of canine mast cell tumors (MCT).
Animals: Twenty-four dogs with cutaneous MCT.
Methods: Dogs with at least 1 measurable, cytologically confirmed, and previously untreated cutaneous MCT received a single treatment with vinorelbine at the previously established dosage of 15 mg/m² IV. Tumor measurements and CBC were evaluated before and 7 days after treatment. Adverse events were graded according to Veterinary Cooperative Oncology Group (VCOG) guidelines.
Statistics: Data were accrued in accordance with a Simon's 2-stage design with a noninteresting response rate of .05, a target response of .25, and α and β values of .10.
Results: Three of 24 dogs (13%) had a response to treatment, including 1 measurable complete response and 1 measurable partial response. The 3rd dog had microscopic complete response to treatment with stable measurable disease. Twenty other dogs (83%) had stable disease and 1 dog (4%) had progressive disease. Neutropenia occurred in 13 dogs (54%) (grade 1, n = 4; grade 3, n = 6; grade 4, n = 3). Gastrointestinal toxicity occurred in 11 dogs (46%) (anorexia: grade 1, n = 3; grade 2, n = 1; grade 3, n = 1; diarrhea: grade 1, n = 2; grade 3, n = 1; vomiting: grade 1, n = 5; grade 3, n = 1).
Conclusions and Clinical Importance: Vinorelbine was associated with an overall response rate of 13% and a high prevalence of neutropenia. Additional studies are indicated to determine if repeated dosing of vinorelbine or combination of vinorelbine with other drugs increases the observed biologic activity against canine MCT.     

Effect of oral administration of L-lysine on conjunctivitis caused by feline herpesvirus in cats

OBJECTIVE: To determine whether oral administration of L-lysine to cats would lessen the severity of conjunctivitis caused by feline herpesvirus (FHV-1). ANIMALS: 8 healthy young adult cats. PROCEDURE: Cats received oral administration of lysine monohydrochloride (500 mg, q 12 h) or placebo (lactose) beginning 6 hours prior to inoculation of virus. The left conjunctival sac received a 50-microl suspension of FHV-1 grown in cell culture (1.8 X 10(8) tissue culture infective dose50) on day 1. Cats were evaluated and scores given for clinical signs each day for 21 days. Samples for virus isolation were collected from the eye and throat every third day. Plasma lysine and arginine concentrations were measured prior to the study and on days 3, 14, and 22. RESULTS: Cats that received lysine had less severe conjunctivitis than cats that received placebo. Virus isolation results did not differ between the groups. Plasma lysine concentration was significantly higher in cats that received lysine, compared with control cats, whereas plasma arginine concentrations did not differ between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of 500 mg of lysine to cats was well tolerated and resulted in less severe manifestations of conjunctivitis caused by FHV-1, compared with cats that received placebo. Oral administration of lysine may be helpful in early treatment for FHV-1 infection by lessening the severity of disease.     

Linear-Accelerator-Based Modified Radiosurgical Treatment of Pituitary Tumors in Cats: 11 Cases (1997–2008)

Objective: Determine the efficacy and safety of a linear-accelerator-based single fraction radiosurgical approach to the treatment of pituitary tumors in cats.
Design: Retrospective study.
Animals: Eleven client-owned cats referred for treatment of pituitary tumors causing neurological signs, or poorly controlled diabetes mellitus (DM) secondary either to acromegaly or pituitary-dependent hyperadrenocortism.
Procedures: Cats underwent magnetic resonance imaging (MRI) of the brain to manually plan radiation therapy. After MRI, modified radiosurgery was performed by delivering a single large dose (15 or 20 Gy) of radiation while arcing a linear-accelerator-generated radiation beam around the cat's head with the pituitary mass at the center of the beam. Eight cats were treated once, 2 cats were treated twice, and 1 cat received 3 treatments. Treated cats were evaluated for improvement in endocrine function or resolution of neurological disease by review of medical records or contact with referring veterinarians and owners.
Results: Improvement in clinical signs occurred in 7/11 (63.6%) of treated cats. Five of 9 cats with poorly regulated DM had improved insulin responses, and 2/2 cats with neurological signs had clinical improvement. There were no confirmed acute or late adverse radiation effects. The overall median survival was 25 months (range, 1–60), and 3 cats were still alive.
Conclusions and Clinical Importance: Single fraction modified radiosurgery is a safe and effective approach to the treatment of pituitary tumors in cats.     

Treatment of oral squamous cell carcinoma with accelerated radiation therapy and concomitant carboplatin in cats

Background: Feline oral squamous cell carcinoma (SCC) carries a very poor prognosis with traditional treatments. Hypothesis/Objectives: To examine the effectiveness of adding carboplatin to a previously published accelerated radiation protocol in the treatments of oral SCC in cats. Animals: Thirty‐one cases of oral SCC in cats. Tumor sites included lingual (n = 9), mandible (n = 10), maxilla (n = 7), tonsil (n = 4), and cheek (n = 1). Methods: Prospective trial using a planned radiation protocol consisting of 14 fractions of 3.5 Gy given within a 9‐day period with the addition of carboplatin given at 90–100 mg/m² on day 1 and day 4.5. Treatments were twice daily with a 6‐hour delay between treatments. All cats presenting with oral SCC without evidence of distant metastasis were eligible. Results: Median survival for all cats was 163 days (range 53–770 days) with a mean of 319 ± 53 days with significant predictors of survival being site (P= .004) and whether there was a complete response at 30 days (P= .001). Cats with tumors of tonsil origin or cheek responded best to therapy and were long‐term survivors with a mean survival of 724 days and the median had not been reached because of continued survival of 4 cats. Conclusions and Clinical Importance: This protocol offers an aggressive yet tolerable treatment of oral SCC in cats that might offer improved survival as compared with previously reported treatments. The long‐term survival of cats with tonsillar SCC has not been reported previously.     

Single-agent gemcitabine chemotherapy in dogs with hepatocellular carcinomas

The goal of this study was to determine the efficacy and tolerability of gemcitabine in dogs diagnosed with hepatocellular carcinoma (HCC). Eighteen dogs were examined retrospectively (4 massive HCC, 10 nodular HCC and 4 diffuse HCC). All dogs received gemcitabine at 350-400 mg m(-2) weekly for 5 weeks. Toxicity was graded using VCOG-CTCAE guidelines and response was monitored with serial abdominal ultrasounds. Fifteen dogs completed all five cycles. Toxicity was minimal and consisted of grade I/II vomiting, anorexia and diarrhoea and two episodes of grade III neutropenia. Median survival time for all dogs was 983 days. Median progression free interval was 971 days. Based on the results of this study, surgery remains the best treatment for HCC, despite incomplete resection. There was no improvement in the survival of those diagnosed with nonresectable HCC treated with gemcitabine chemotherapy.     

Safety and efficacy of high‐dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats

Objective – To determine the safety and efficacy of high‐dose fomepizole compared with ethanol (EtOH) in cats with ethylene glycol (EG) toxicosis. Design – Prospective study. Setting – University veterinary research laboratory. Animals – Thirteen cats. Interventions – Two cats received injections of high‐dose fomepizole (Study 1). Three cats received lethal doses of EG and fomepizole treatment was initiated 1, 2, or 3 hours later (Study 2). Eight cats received a lethal dose of EG and were treated with fomepizole or EtOH (Study 3). Cats treated with fomepizole received 125 mg/kg IV initially, then 31.25 mg/kg at 12, 24, and 36 hours. Cats treated with EtOH received 5 mL of 20% EtOH/kg IV initially, then every 6 hours for 5 treatments, then every 8 hours for 4 treatments. Cats also received fluids and supportive therapy as needed. Measurements and Main Results – Clinical signs were monitored and serial blood analyses performed. Cats receiving fomepizole experienced mild sedation but no biochemical evidence of toxicity. Cats receiving fomepizole for EG intoxication survived if therapy was initiated within 3 hours of EG ingestion. One of the 6 developed acute renal failure (ARF) but survived. Only 1 of the 3 cats treated with EtOH 3 hours following EG ingestion survived; 2 developed ARF and were euthanized. Cats treated 4 hours following EG ingestion developed ARF, whether treated with EtOH or fomepizole. Conclusions – Fomepizole is safe when administered to cats in high doses, prevents EG‐induced fatal ARF when therapy is instituted within 3 hours of EG ingestion, and is more effective than treatment with EtOH.     

Clinical evaluation of Alfaxan-CD® as an intravenous anaesthetic in young cats

Objective   To describe and evaluate the use of Alfaxan-CD ® as an intravenous anaesthetic in young cats.
Design   Thirty-five Domestic Short-hair cats aged from 3 to 12 months were admitted into the University Veterinary Teaching Hospital-Sydney for elective surgery. Anaesthesia was induced with Alfaxan-CD® and maintained with isoflurane: 22 cats received no premedication and 13 cats received acepromazine (0.03 mg/kg) and butorphanol (0.3 mg/kg) subcutaneously 30 min prior to induction.
Qualitative and quantitative data for induction and recovery were recorded. Physiological parameters were recorded at 0, 2 and 5 min post induction, and every 5 min thereafter until the end of the procedure.
Results   Intravenous injection of Alfaxan-CD® resulted in rapid induction of anaesthesia with a mean time to intubation of 122 s. The mean dose of Alfaxan-CD® used was 4.2 mg/kg in unpremedicated cats and 2.7 mg/kg in premedicated cats. All cats maintained a heart rate above 95 beats/min. No cat developed hypoxaemia. Hypercapnoea was detected in 4 cats and hypotension was observed in 18 cats. Time to extubation ranged from 1 to 9 min. The mean time to sternal recumbency for premedicated cats was 11 min; 77% of premedicated cats and 23% of unpremedicated cats had a recovery score of 1 or 2.
Conclusion   Alfaxan-CD® is an effective anaesthetic agent in young healthy cats, providing a smooth induction and rapid recovery. Cats that were premedicated with acepromazine and butorphanol prior to induction with Alfaxan-CD® had better recovery scores than those that were not premedicated.     

Duration of serologic response to three viral antigens in cats

OBJECTIVE: To determine whether vaccinated cats either remained seropositive or responded serologically to revaccination against 3 key viral antigens after extended periods since their last vaccination. DESIGN: Serologic survey. ANIMALS: 272 healthy client-owned cats. PROCEDURE: Cats were > or = 2 years old and vaccinated for feline panleukopenia virus (FPV), feline calicivirus (FCV), and feline herpesvirus (FHV). On day 0, cats were revaccinated with a vaccine from the same line of vaccines as they had historically received. Antibody titers were measured in sera collected on day 0 (prevaccination titer) and 5 to 7 days later (postvaccination titer). Cats were considered to have responded serologically if they had a day-0 hemagglutination inhibition titer to FPV > or = 1:40, serum neutralization (SN) titer to FCV > or = 1:32, SN titer to FHV > or = 1:16, or > or = 4-fold increase in antibody titer after revaccination. RESULTS: The percentage of cats that had titers at or above the threshold values or responded to revaccination with a > or = 4-fold increase in titer was 96.7% for FPV, 97.8% for FCV, and 88.2% for FHV. CONCLUSIONS AND CLINICAL RELEVANCE: In most cats, vaccination induced a response that lasted up to and beyond 48 months for all 3 antigens. Although not equivalent to challenge-of-immunity studies as a demonstration of efficacy, results suggest that revaccination with the vaccine used in our study provides adequate protection even when given less frequently than the traditional 1-year interval. The study provides valuable information for clinicians to determine appropriate revaccination intervals.     

Use of surgery and electron beam irradiation, with or without chemotherapy, for treatment of vaccine-associated sarcomas in cats: 78 cases (1996-2000).

OBJECTIVE: To evaluate responses of cats with vaccine-associated sarcomas to treatment with surgery and radiotherapy, with or without adjunctive chemotherapy. DESIGN: Retrospective study. ANIMALS: 76 cats (78 tumors). PROCEDURE: Medical records were reviewed. Factors potentially associated with survival time, time to recurrence, and time to development of metastases were evaluated. RESULTS: Following excision, electron beam radiation, and, in some cases, chemotherapy, 32 (41%) cats experienced recurrence, and 9 (12%) cats developed metastases. One- and 2-year survival rates were 86 and 44%, respectively. Median survival time from onset of disease was 730 days (range, 30 to 2,014 days). Median disease-free interval was 405 days (range, 30 to 925 days). Cats that underwent only 1 surgery prior to radiotherapy had a lower recurrence rate than did cats that underwent > 1 surgery and had a significantly longer disease-free interval. Survival time and disease-free interval decreased as time between surgery and the start of radiotherapy increased. Cats that developed metastases had significantly shorter survival times and disease-free intervals than did cats that did not develop metastases. Castrated male cats had a significantly shorter survival time than did spayed female cats. Cats with larger tumors prior to the first surgery had shorter survival times. Twenty-six cats received chemotherapy in addition to surgery and radiotherapy. Whether cats received chemotherapy was not associated with recurrence rate, metastasis rate, or survival time. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that excision followed by electron beam irradiation may be beneficial for treatment of cats with vaccine-associated sarcomas. Extent of excision prior to radiotherapy did not seem to be associated with recurrence rate.     

A comparison of four methods of analgesia in cats following ovariohysterectomy

OBJECTIVE: To evaluate the effectiveness of preoperative administration of oral carprofen, subcutaneous ketoprofen, and local nerve block with bupivacaine in preventing postoperative pain-associated behavior in cats after ovariohysterectomy. ANIMALS: Fifty-two female intact cats. Materials and methods Cats received butorphanol (0.44 mg kg(-1) IM), carprofen (2.2 mg kg(-1) PO), ketoprofen (2.2 mg kg(-1) SQ), or bupivacaine infiltration block (1.1 mg kg(-1) SQ) before surgery. Cortisol and drug concentrations and visual analog scale (VAS) and interactive visual analog scale (IVAS) pain-associated behavior scores were measured 2 hours before and 0, 1, 2, 4, 8, 12, and 24 hours after ovariohysterectomy. RESULTS: Cats receiving butorphanol had significantly increased IVAS scores 2 hours after surgery compared with baseline measurements. Cats receiving carprofen, ketoprofen, and bupivacaine had significant increases from baseline in VAS and IVAS scores 1 and 2 hours after surgery. VAS and IVAS scores for cats receiving bupivacaine were significantly greater 1 and 2 hours after surgery than for cats that received butorphanol. Cats receiving carprofen had significant increases in cortisol 1 hour after surgery and significant decreases 24 hours after surgery compared with baseline measurements. CONCLUSIONS AND CLINICAL RELEVANCE: Preoperative carprofen and ketoprofen have effects on pain-associated behavior similar to butorphanol in cats undergoing ovariohysterectomy. Cats receiving bupivacaine blocks may require additional analgesics immediately after surgery.