Service d’hématologie clinique, CHU Amiens, France
Myeloma is rarely diagnosed at a young age, with fewer than 2% of patients being diagnosed before the age of 40. The characteristics and outcome of this particular population are poorly understood. In this article, we present 214 patients who were 40 years of age or younger at the time of diagnosis of myeloma and related conditions in the 2000s. Of these, 189 had symptomatic myeloma, and their baseline characteristics were broadly similar to those of older patients, except for a higher proportion with a poor prognostic ISS score (ISS-1). In total, 90% received intensified therapy followed by first-line autologous stem cell transplantation, and nearly 25% received an allograft, mainly on first or second relapse. With a median follow-up of 76 months, the estimated median survival was 14.5 years. At five years, overall survival was 84%. Based on multivariate analysis, a high ISS score (ISS-3; HR = 2.14; p = 0.03), unfavourable cytogenetics (HR = 4.54; p < 0.0001), bone lesions (HR = 3.95; p = 0.01), or disease progression (HR = 12.78; p < 0.0001) conferred a shorter survival. Given the low risk of death in the general population of the same age, the relative survival of these patients was relatively close to overall survival (83%), with a 70-fold increased risk of mortality despite their prolonged survival.