Clinical and pathologic study of canine lymphoma: clinical staging, cell classification, and therapy

A prospective study of 100 naturally occurring canine lymphomas was conducted. All lymphomas were clinically staged and pathologically classified according to criteria used in human patients. Four chemotherapy schedules were evaluated, and animals were monitored constantly. Percent remissions, mean remisson durations, and survival times were correlated with clinical stages, cell classification, and therapy schedules. Most dogs presented in stage III, classified histologically as undifferentiated or stem cell types, with fine chromatin patterns in fresh imprints. The histiocytic type and stippled chromatin pattern were second most frequent pathological classifications, and this group generally had the highest percent remissions and the longest mean survival periods. The highest percent remissions (79%) and the longest mean remission durations (184 days) were achieved with combined vincristine cyclophosphamide prednisone therapy, regardless of clinical stage or cell type. There was no correlation between clinical staging and cell classification, and cell types did not vary with tumor location or disease progression. Bacterial sepsis and drug toxicity were the major causes of death, and splenectomies performed in 21 dogs reduced survival times. The value of canine lymphomas as models for clinical studies of non Hodgkin lymphomas is discussed.