OBJECTIVETo investigate the clinical characteristics and prognosis of very young patients with multiple myeloma (MM).

METHODSWe retrospectively analyzed the clinical characteristics and outcome of 35 newly diagnosed MM patients 40 years old or younger during a period of 15 years and compared with published data from western countries.

RESULTSOur study demonstrated that these very young patients were more likely to be in advanced stage of International staging system, IgD isotype, hemoglobin<100 g/L, decreased platelets and deletion of 17p13. With a median follow-up of 17 months (1- 89 months), the median overall survival (OS) of this cohort was 33 months and progression-free survival (PFS) was 13 months, moreover 8 of 17 deaths occurred in the first year after diagnosis. In the univariate analysis, extramedullary infiltration, del (17p13）and renal impairment were associated with reduced PFS (P=0.031, P=0.015, P=000, respectively), while the last two factors also predicted inferior OS (P=0.015, P=0.001), but multivariate analysis showed that only renal impairment independently associated with inferior survival in COX model（PFS: HR=3.953, 95% CI 1.263-12.371, P=0.018; OS: HR=5.769, 95% CI 1.602- 20.771, P=0.007).

CONCLUSIONOur research showed for the first time that the clinical characteristics and survival of MM patients ≤ 40 years old in China were different from that in western countries. The special attention should be paid to the patients with their diagnosis and treatment.