Body surface area-based chemotherapy dosing in lymphoma: Variation across clinician-reported practice, real-world data, and randomized trial reporting

Abstract Body surface area (BSA)-based chemotherapy dosing requires decisions regarding calculation formula, weight reassessment, dose rounding, and BSA capping. We hypothesized that these practices vary in routine lymphoma care, that such variation may affect a substantial proportion of patients, and that clinician-reported practice differs from dosing information reported in randomized controlled trials (RCTs). We conducted a multicomponent descriptive study comprising a nationwide survey of Danish hematologists, an anthropometric analysis of 152 consecutive patients with large B-cell lymphoma, and a targeted review of 26 phase II-III lymphoma RCTs published during 2020–2025. Among 53 eligible physicians, 57% reported using a general BSA cap, with additional variation in BSA formula, weight reassessment, dose rounding, and empirical dose adjustment. In the patient cohort, 36% had baseline BSA > 2.0 m² and 13% >2.2 m²; 17% experienced a weight change > 10%, while only 2% had a BSA change > 10%. Overall, 41% of patients had a dose modification, but none were attributed to BSA capping. All RCTs contained a BSA-based treatment component, and no general BSA cap was identified, although BSA formula, weight basis, and reassessment were rarely reported. These findings demonstrate substantial variation in clinician-reported BSA dosing practice, incomplete reporting in contemporary trials, and a notable contrast between frequent self-reported capping and its absence in the separate real-world cohort. The clinical consequences require evaluation using cycle-level dosing and outcome data.