Clinical Outcome of Multicentric Lymphoma Treated with Cyclophosphamide, Doxorubicin, Vincristine, and Prednisolone (CHOP) in Small Breed Dogs

Abstract

Lymphoma is one of the most common malignant tumors in dogs. Combination chemotherapy with vincristine, cyclophosphamide, doxorubicin, and prednisolone (CHOP) is the most effective treatment for multicentric lymphoma. Previous studies have evaluated the response of large dogs to CHOP treatment and identified prognostic factors; however, studies on small dogs are lacking. In this study, we investigated the outcomes and prognostic factors for small dogs with multicentric lymphoma treated with CHOP. The responses of patients to CHOP treatment were assessed, and 54.3% were evaluated as being in complete remission (CR), 31.4% in partial remission (PR), and 14.3% in no remission (NR). The overall response rate was 85.7%. The median survival times for CR, PR, and NR patients were 683 days (85-1496 days), 241 days (15-777 days), and 119 days (61-308 days), respectively. Among the CR patients, survival was longer under the following conditions: age under 10 years (p = 0.011), no cardiovascular heart disease (p = 0.046), and no history of hospitalization due to side effects from chemotherapy (p = 0.002). These results might help clinicians build treatment plans for multicentric lymphoma in small breed dogs.

Keywords: CHOP protocol; lymphoma; prognostic factors; small breed dog; survival time.

Figure 1

Variation in survival time in each response group. Median survival time is 683 days in CR, 241 days in PR, and 119 days in NR. The CR group survived statistically significantly longer than PR or NR groups (p = 0.002, p = 0.002 respectively).

Figure 2

Distribution of different survival times according to influencing factors in the CR group (n = 19). (A) Ten years of age, (B) presence of CVHD, and (C) hospitalization made a difference in the survival time. The three factors negatively affected the survival time (p = 0.011, p = 0.046, and p = 0.002, respectively).