Association between bariatric surgery and outcomes in chronic myeloid leukemia

Background: Bariatric surgery is the most effective weight loss intervention. However, it can also decrease the bioavailability of oral medications. Tyrosine kinase inhibitors, the mainstay treatment for chronic myeloid leukemia (CML), are the most successful example of an oral targeted therapy. The impact of bariatric surgery on CML outcomes is unknown. Methods: In a retrospective analysis, we screened 652 patients with CML and identified 22 with prior bariatric surgery, and compared their outcomes to a matched cohort of 44 patients with no prior bariatric surgery. Results: The rate of early molecular response (3-month BCR::ABL1 < 10% International Scale) was lower in the bariatric surgery group compared with the control group (68% vs. 91%; p =.05), with longer median times to achieve complete cytogenetic (6 vs. 3 months; p =.001) or major molecular responses (12 vs. 6 months; p =.001). Bariatric surgery was associated with inferior event-free survival (5-year, 60% vs. 77%; p =.004) and failure-free survival (5-year, 32% vs. 63%; p <.0001). In a multivariate analysis, bariatric surgery was the only independent predictor for the risk of treatment failure (hazard ratio, 9.40; 95% CI, 2.71–32.55; p =.0004) or event-free survival (hazard ratio, 4.24; 95% CI, 1.67–12.23; p =.008). Conclusions: Bariatric surgery is associated with suboptimal responses that require adapted treatment strategies.