Clinical outcome and prognostic factors in dogs with B‐cell chronic lymphocytic leukemia: A retrospective study

Abstract

Background: B-cell chronic lymphocytic leukemia (BCLL) in dogs generally is considered an indolent disease, but previous studies indicate a wide range in survival times.Objectives: We hypothesized that BCLL has a heterogeneous clinical course, similar to chronic lymphocytic leukemia in humans. We aimed to assess presentation and outcome in dogs with BCLL and evaluate the prognostic relevance of clinical and flow cytometric factors. Animals: One hundred and twenty-one dogs with BCLL diagnosed by flow cytometry. Three breed groups were represented: small breed dogs (n = 55) because of increased risk of BCLL; Boxers (n = 33) because of preferential use of unmutated immunoglobulin genes; and other breeds (n = 33). Methods: Retrospective study reviewing signalment, clinicopathologic data, physical examination findings, treatment, and survival of dogs with BCLL. Cellular proliferation, determined by the percentage of Ki67-expressing CD21+ B-cells by flow cytometry, was measured in 39 of 121 cases. Clinical and laboratory variables were evaluated for association with survival. Results:The median survival time (MST) for all cases was 300 days (range, 1-1644 days). Boxers had significantly shorter survival (MST, 178 days) than non-Boxers (MST, 423 days; P < .0001), and no significant survival difference was found between small breeds and other non-Boxer breeds. Cases with high Ki67 (>40% Ki67-expressing B-cells) had significantly shorter survival (MST, 173 days) than did cases with <40% Ki67 (MST undetermined; P = .03), regardless of breed. Cases with a high lymphocyte count (>60 000 lymphocytes/μL) or clinical signs at presentation had significantly shorter survival.Conclusions and Clinical Importance: B-cell chronic lymphocytic leukemia had a variable clinical course and Boxer dogs and cases with high Ki67 had more aggressive disease.

Clinical outcome and Ki67 evaluation in dogs with nodal small cell B‐cell lymphoma diagnosed by flow cytometry

“…12,25 However, dogs with lymphocytosis in this study appeared to have a much more aggressive clinical course with an OS of 133 days, as compared to a MST of 300 to 480 days 12,24 for dogs with BCLL, despite a majority of dogs having a lymphocytosis of <60 000/μL which was associated with an improved prognosis for dogs with BCLL. 12 MCL, another subtype comprised of small to intermediate-sized B-cells, primarily affects the spleen in dogs and nodal MCL appears quite uncommon. 3,20,21 We hypothesized that Ki67 expression, which is a marker of cellular proliferation, would be a useful prognostic factor for small cell B-cell lymphoma.…”

“…12,24 It is possible dogs with BCLL were included in this study as a subset of BCLL cases can have nodal involvement. 12,25 However, dogs with lymphocytosis in this study appeared to have a much more aggressive clinical course with an OS of 133 days, as compared to a MST of 300 to 480 days 12,24 for dogs with BCLL, despite a majority of dogs having a lymphocytosis of <60 000/μL which was associated with an improved prognosis for dogs with BCLL. 12 MCL, another subtype comprised of small to intermediate-sized B-cells, primarily affects the spleen in dogs and nodal MCL appears quite uncommon.…”

“…We previously measured Ki67 expression on control B-cells from healthy dog blood and lymph node samples (n = 12). 12…”

P-Glycoprotein Activity at Diagnosis Does Not Predict Therapy Outcome and Survival in Canine B-Cell Lymphoma

“…The estimated median RFP and lymphoma related survival time for all dogs were 414 days (95% confidence interval (CI), range 228–600 days) and 442 days (95% CI, range 236–648 days), respectively, in a study published by Pioggi et al [ 49 ]. Another study reported 121 cases treated by chemotherapy, with a median survival time (MST) of 300 days (range 1–1644 days) [ 50 ]. In yet another study, median RFP was 196 days (range 22–1656 days) and OST was 292 days (range 40–2246 days) of dogs receiving CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) based protocols [ 51 ].…”

An aggressive CD4−CD8− T‐cell neoplasm in young English bulldogs

“…In fact, many bulldogs were started on prednisone and chlorambucil with a presumptive diagnosis of chronic lymphocytic leukaemia based on blood film review. In humans and dogs, B‐cell chronic lymphocytic leukaemia (B‐CLL) is considered an indolent disease, in which many patients with early‐stage disease can be monitored without therapy 1,16–19 . Polyclonal B‐cell lymphocytosis of English bulldogs (PBLEB), a recently described non‐neoplastic disease of predominantly young, male English bulldogs is also indolent and characterized by an expansion of small mature B lymphocytes without peripheral lymph node involvement 13 .…”