Prevalence and prognostic impact of hypocobalaminemia in dogs with lymphoma.

OBJECTIVE

To determine the prevalence of hypocobalaminemia in dogs with multicentric lymphoma and to investigate any relationship between serum cobalamin concentration and disease outcome.

DESIGN

Cohort study.

ANIMALS

58 dogs with multicentric lymphoma.

PROCEDURES

Serum cobalamin concentrations were measured in 58 dogs with multicentric lymphoma. Clinical signs, stage, and immunophenotype for dogs with hypocobalaminemia were compared with those for dogs with serum cobalamin concentrations above the lower end of the reference range. Survival times for dogs undergoing a cyclic multidrug chemotherapy protocol (n = 53) were similarly compared. Serum cobalamin concentrations for treated dogs that died or were euthanized before day 60 were compared with those of dogs still alive at day 60.

RESULTS

Serum cobalamin concentrations ranged from < 150 to 1,813 ng/L, with a median concentration of 401 ng/L. Nine of the 58 (16%) dogs had hypocobalaminemia (serum cobalamin concentration < 252 ng/L). Three of 9 dogs with hypocobalaminemia survived to at least day 60, compared with 40 of 44 (91%) dogs without hypocobalaminemia (serum cobalamin concentration >or= 252 ng/L). Ten (10/53 [19%]) dogs undergoing a cyclic multidrug chemotherapy protocol died before day 60, and the median serum cobalamin concentration for these dogs (232 ng/L) was significantly lower than for those still alive at the end point of the study (556 ng/L).

CONCLUSIONS AND CLINICAL RELEVANCE

Hypocobalaminemia was relatively uncommon in this population of dogs with multicentric lymphoma, but was associated with a poor outcome. Serum cobalamin concentrations may provide prognostic information in dogs with multicentric lymphoma.