Fluctuations of NTproBNP levels during RdC. (A) NTproBNP (median) and eGFR per cycle for all patients (the number of evaluable patients at each cycle is indicated). (B) NTproBNP (median) and eGFR per cycle only for patients who completed at least 6 cycles (n = 17). An increase in NTproBNP ≥ 30% and ≥ 300 ng/L after the first cycle of RdC was observed. A reduction of NTproBNP toward the baseline levels was observed after the third cycle. This transient increase of NTproBNP was observed in patients with no overt cardiac involvement and in patients with cardiac involvement. The increase in NTproBNP was not associated with fluctuations of eGFR and was in discordance with FLC levels, which were either dropping or stable.