This retrospective study examined the use of CCNU (1-[2-chloroethyl]3-cyclohexyl-1-nitrosurea) in 36 dogs with epitheliotropic lymphoma. Thirty-one (86%) dogs had the cutaneous form of disease, and 5 (14%) dogs had the oral form of disease. Nineteen (51%) dogs were treated with other chemotherapeutic agents before receiving CCNU. All dogs had detectable disease at the time CCNU therapy was initiated. Dogs received a median starting CCNU dosage of 70 mg/m2 (range, 50-100 mg/m2). The median number of treatments administered was 3 (range, 1-12 treatments). After the initial treatment, the CCNU dosage was adjusted in 9 of 26 (35%) dogs in which CCNU was continued: 7 had dosage reductions, and 2 had dosage escalations. Twenty-eight of 36 (78%) dogs had a measurable response to CCNU for a median duration of 106 days (95% confidence interval [CI], 75-182). Six dogs (17%) had a complete response, including 5 dogs with the cutaneous form and 1 dog with the oral form. Twenty-two dogs (61%) had a partial response, including 20 dogs with the cutaneous form and 2 dogs with the oral form, for a median duration of 88 days (95% CI, 62-170). Toxicoses after CCNU chemotherapy included myelosuppression in up to 29% of the dogs, gastrointestinal signs in up to 22% of the dogs, and liver enzyme activity increases in up to 86% of the dogs. This study demonstrates that CCNU chemotherapy can be considered a reasonable option for the treatment of canine epitheliotropic lymphoma in dogs.

One hundred seventy-nine tumor-bearing dogs were treated with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) between 1995 and 2001. CCNU was given as a single dose of 50-110 mg/m 2 body surface area PO. Treatment interval varied, but the minimal interval between CCNU doses was 3 weeks. After treatment, 11 dogs (6.1%) developed hepatic toxicity. The median number of CCNU doses and the median total cumulative CCNU dose were significantly higher in dogs that developed hepatic toxicity (4 doses; 350 mg/m 2 ) than in dogs without hepatic damage (3 doses; 230 mg/m 2 ). Median duration to detection of hepatic toxicity from the last dose of CCNU was 11 weeks (range 2-49 weeks). Common biochemical abnormalities were abnormally high serum liver enzyme activities and hypoalbuminemia. Six dogs with CCNU-associated hepatic toxicity had ascites, and 3 dogs had concurrent pleural effusion. Serum concentrations of bile acids were abnormally high in 4 of 5 dogs tested. Percutaneous ultrasound-guided liver biopsies were performed in 10 dogs, and findings were nonspecific and chronic in nature. Seven dogs were euthanized because of progressive liver failure, and their median survival from diagnosis of liver disease was 9 weeks. Three dogs died of other causes and 1 dog of unknown cause. Although clinical signs resolved in 3 dogs, biochemical abnormalities and histopathologic lesions persisted 4 to 38 months from the time of diagnosis of liver disease. Our findings suggest that CCNU can cause delayed, cumulative dose-related, chronic hepatotoxicity that is irreversible and can be fatal.

A chemotherapy protocol using a consolidation phase of alkylating agents was used for treating 94 dogs with lymphoma. Fifty-seven percent of dogs were in stage V, 63% were ill and 38% had T-cell lymphoma. The complete remission (CR) rate was 70% and is comparable to results achieved with previously published chemotherapy protocols. Anorexia predicted the remission; of the 40 dogs without anorexia, 35 (88%) achieved CR whereas of 52 dogs with anorexia, 30 (58%) achieved CR. Median first CR duration was 168 days and 1- and 2-year CR rates were 17.4 and 15.5%, respectively. Platelet count affected length of first CR, with a 53.2% reduced chance of coming out of remission with each log increase in platelet count. Median survival time was 302 days. One and 2-year survival rates were 44 and 13%, respectively. Anorexia and no dose reduction of any drug were independent negative variables. Of 93 dogs with toxicity data, 65 dogs (70%) required a dose reduction. Cyclophosphamide was most commonly reduced with reductions in 31 (38%) of 82 dogs. A dose reduction was significantly more likely in dogs with B-cell lymphoma than in those with T-cell lymphoma.

One hundred seventy-nine tumor-bearing dogs were treated with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) between 1995 and 2001. CCNU was given as a single dose of 50-110 mg/m2 body surface area PO. Treatment interval varied, but the minimal interval between CCNU doses was 3 weeks. After treatment, 11 dogs (6.1%) developed hepatic toxicity. The median number of CCNU doses and the median total cumulative CCNU dose were significantly higher in dogs that developed hepatic toxicity (4 doses; 350 mg/m2) than in dogs without hepatic damage (3 doses; 230 mg/m2). Median duration to detection of hepatic toxicity from the last dose of CCNU was 11 weeks (range 2-49 weeks). Common biochemical abnormalities were abnormally high serum liver enzyme activities and hypoalbuminemia. Six dogs with CCNU-associated hepatic toxicity had ascites, and 3 dogs had concurrent pleural effusion. Serum concentrations of bile acids were abnormally high in 4 of 5 dogs tested. Percutaneous ultrasound-guided liver biopsies were performed in 10 dogs, and findings were nonspecific and chronic in nature. Seven dogs were euthanized because of progressive liver failure, and their median survival from diagnosis of liver disease was 9 weeks. Three dogs died of other causes and 1 dog of unknown cause. Although clinical signs resolved in 3 dogs, biochemical abnormalities and histopathologic lesions persisted 4 to 38 months from the time of diagnosis of liver disease. Our findings suggest that CCNU can cause delayed, cumulative dose-related, chronic hepatotoxicity that is irreversible and can be fatal.

This retrospective study examined the use of CCNU (1-[2-chloroethyl]3-cyclohexyl-1-nitrosurea) in 36 dogs with epitheliotropic lymphoma. Thirty-one (86%) dogs had the cutaneous form of disease, and 5 (14%) dogs had the oral form of disease. Nineteen (51%) dogs were treated with other chemotherapeutic agents before receiving CCNU. All dogs had detectable disease at the time CCNU therapy was initiated. Dogs received a median starting CCNU dosage of 70 mg/m2 (range, 50-100 mg/m2). The median number of treatments administered was 3 (range, 1-12 treatments). After the initial treatment, the CCNU dosage was adjusted in 9 of 26 (35%) dogs in which CCNU was continued: 7 had dosage reductions, and 2 had dosage escalations. Twenty-eight of 36 (78%) dogs had a measurable response to CCNU for a median duration of 106 days (95% confidence interval [CI], 75-182). Six dogs (17%) had a complete response, including 5 dogs with the cutaneous form and 1 dog with the oral form. Twenty-two dogs (61%) had a partial response, including 20 dogs with the cutaneous form and 2 dogs with the oral form, for a median duration of 88 days (95% CI, 62-170). Toxicoses after CCNU chemotherapy included myelosuppression in up to 29% of the dogs, gastrointestinal signs in up to 22% of the dogs, and liver enzyme activity increases in up to 86% of the dogs. This study demonstrates that CCNU chemotherapy can be considered a reasonable option for the treatment of canine epitheliotropic lymphoma in dogs.