P101 | The long term prognostic impact of chromosome 1 abnormalities in newly diagnosed multiple myeloma patients

Introduction. In Multiple Myeloma (MM) the cytogenetic abnormalities del(17p), t(4;14), and t(14;16) have been previously recognized as the most significant one with a negative prognostic impact and incorporated into the R-ISS staging system. More recently chromosome 1 abnormalities have shown a possible prognostic adverse impact with discordant results. In this study we have investigated the prognostic role of chromosome 1 abnormalities in newly diagnosed MM patients (NDMM).Methods. We performed a retrospective study enrolling 95 patients with NDMM between 2017 and 2022. Patients were stratified into eligibles and ineligibles to autologous stem cell transplant (ASCT) according to the age and the comorbidities. The disease-free survival (PFS), overall survival (OS), and the time from first-line therapy to the need for second-line therapy (TTNT) were analyzed by Kaplan–Meier and log-rank test. The association of the cytogenetic factors and outcomes were assessed by Cox proportional-hazards models. Analyses were performed in R (v4.3) using survival and survminer packages.Results. At baseline 58% of patients were defined as high risk (HR) an 42% as standard risk (SR); t(4;14) was present in 8.4%, t(14;16) in 2.1%, del(13p) in 47%, del(17p) in 19% (cut-off>20%) del(1p) in 21%, gain(1q) in 28% and amp(1q) in 17%.With a median follow-up of 66 months, the median PFS was 30 months, the TTNT was 50 months, with an OS of 50 months.SR patients showed a better prognosis rather than the HR ones (PFS p=0.014, OS p= 0.03). The presence of del(17p) showed a significant impact (PFS p0.001, OS p