The Relative Dose Intensity Changes during Cycles of Standard Regimens in Patients with Diffuse Large B-Cell Lymphoma

No studies have focused on the trajectory of the average relative dose intensity (ARDI) during cycles of first-line chemotherapy for patients with diffuse large B-cell lymphoma. To evaluate the impact of attenuating ARDI during cycles on overall survival, we conducted a multi-centre, longitudinal, observational retrospective study. A total of 307 analysable patients were enrolled. Multivariate Cox hazards modelling with restricted cubic spline models revealed prognostic benefits of higher ARDI up to, but not after, cycle 6. According to group-based trajectory modelling, patients were classified into five groups depending on the pattern of ARDI changes. Among these, two groups in which ARDI had fallen significantly to less than 50% by cycles 4-6 displayed significantly poorer prognosis, despite increased ARDI in the second half of the treatment period (log-rank p = 0.02). The Geriatric Nutritional Risk Index offered significant prediction of unfavourable ARDI changes (odds ratio 2.540, 95% confidence interval 1.020-6.310; p = 0.044). Up to cycle 6, maintenance of ARDI in all cycles (but particularly in the early cycles) is important for prognosis. Malnutrition is a significant factor that lets patients trace patterns of ARDI changes during cycles of chemotherapy associated with untoward prognosis.