Response-adjusted ISS (RaISS) is a simple and reliable prognostic scoring system for predicting progression-free survival in transplanted patients with multiple myeloma.

Complete response (CR) is associated with better outcome in patients with multiple myeloma (MM) treated with autologous transplant even though the progression-free survival (PFS) can be very variable among patients with good response. No simple and reliable prognostic scoring system, able to predict the duration of response, are so far available. Aim of this study was to identify any correlation between baseline clinical findings, response after transplant and the length of PFS, and thus develop a prognostic model. The new prognostic model was developed in a learning cohort of 549 patients with MM transplanted in five Italian hospitals. The prognostic value of this new score was confirmed in a validation cohort of 276 distinct patients with MM transplanted in two different Italian hospital. Univariate and multivariate analyses were performed using Cox models. The most important independent baseline predictor of transplant outcome, together with response after transplant, was International Staging System (ISS). We thus incorporated response to transplant and baseline ISS in a new scoring system, named response-adjusted international scoring system (RaISS), that was able to classify patients in three risk groups (low, intermediate, high) with different probabilities of progression after transplant (median PFS 35.9-15.4 months). The prognostic value of this new score was confirmed in the validation cohort. In conclusion, RaISS is a new simple and easily available scoring system that, accurately defining the risk of progression, can allow to identify patients who could deserve further treatment after transplant (consolidation, maintenance).