Stage Migration in Dogs with Lymphoma

Abstract

Various diagnostic tests have been used to assign a clinical stage to dogs with lymphoma. As more sensitive staging methods are introduced, dogs are reclassified as having a higher disease stage, thereby affecting comparisons of dogs across differently staged clinical trials, and possibly, prognosis. The addition of more sensitive staging tests causes stage migration in dogs with lymphoma. Fifty-nine client-owned dogs with previously untreated cytologically or histologically confirmed lymphoma For every dog, the World Health Organization stage classification (I-V) was based on 5 groupings of various diagnostic tests: A (physical examination [PE] and quantitative blood count [QBC]), B (PE, QBC, thoracic and abdominal radiographs), C (PE, complete blood count with blood-smear evaluation [CBC], thoracic and abdominal radiographs), D (PE, CBC, thoracic radiographs, abdominal ultrasound), and E (PE, CBC, thoracic radiographs, abdominal ultrasound, and bone-marrow cytology). Dogs were treated with doxorubicin-based protocols. There was migration between all of the staging methods except D to E. However, the stage was not a predictor of remission rate, remission duration, or survival, regardless of staging method used. These data emphasized the need for standardized methods to determine the clinical stage in dogs with lymphoma.