Determinants of 15-Year Progression-Free Survival in Multiple Myeloma; Real-World Data From a Single Institution

The therapeutic advances during the last two decades have rendered multiple myeloma a chronic disease and, thus, it is important to identify patient subgroups which may have extremely favorable outcomes and optimize their treatment. The current study aimed to evaluate the clinical and disease characteristics of patients with very long follow-up (minimum 15 years), to identify those with very long survival (> 15 years) and those with very long disease remissions (> 15 years) after frontline treatment diagnosed at a single center from 1994 to 2009. Among 323 consecutive, unselected patients, the calculated 15-year and 20-year cumulative survival rates were 18% and 14%, respectively. Forty-nine survived for more than 15 years. Furthermore, the calculated 15-year and 20-year cumulative PFS rates for the 323 patients were 9% and 7%, respectively; 25 (8%) patients were identified as long-term progression-free survivors. Younger age (≤ 65 years), good performance status (ECOG PS 0-1), low/intermediate risk stratification (ISS 1 or 2), absence of adverse cytogenetic abnormalities, autologous transplantation and achievement of CR to initial therapy were significantly associated with prolonged PFS. Importantly, all patients who were in complete response with negative minimal residual disease at 15 years remained at the same disease status at last follow-up. In conclusion, among patients treated with either conventional chemotherapy or with first-generation novel agents (thalidomide, bortezomib, or lenalidomide), about 15% were long-term survivors and 8% remained in long-term remission for more than 15 years without maintenance treatment.