Overall survival according to group (dFLC <50 or ≥50 mg/L) and first-line treatment. Kaplan-Meyer plots depict overall survival. (A) Entire cohort. Median overall survival: 31.2 months (dFLC ≥50 mg/ml) vs not reached (dFLC <50 mg/L). (B) Bortezomib-based chemotherapy. Median overall survival: 23.0 months (dFLC ≥50 mg/L) vs not reached (dFLC <50 mg/L). (C) Melphalan-dexamethasone. Median overall survival: 19.6 months (dFLC ≥50 mg/L) vs 92.0 months (dFLC <50 mg/L). (D) HDM followed by autologous stem cell transplantation. Median overall survival: 99.3 months (dFLC ≥50 mg/L) vs not reached (dFLC <50 mg/L).