Multiple Myeloma (MM) in Young Patients (pts): Clinical Features and Outcome in 259 Patients Younger Than 40 Years in Comparison to 8,296 pts Aged ≥ 40 Years.

Abstract MM has a median age at presentation of 65–68 years, rarely occurring in pts before age 40. Here, we present clinical, laboratory and survival data in the largest ever-analyzed cohort of young pts compared with pts aged ≥ 40 years. 259 pts aged < 40 and 8,296 aged ≥ 40 years were enrolled. These 8.555 pts were part of the cohort analyzed for the ISS staging project. Previously untreated pts entered into randomized trials with standard (SDT) or high dose treatment (HDT). Clinical data were available for all pts, 526 pts had karyotypic analysis and 454 pts testing for Del 13 testing by FISH. The Chi-Square test was used to identify significant prognostic factors. A maximum likelihood model was used to estimate relative excess risk (RER) for younger versus older pts treated with SDT or HDT. Observed survival was adjusted by life expectancy depending on age, gender, and nationality. Young pts had significantly lower ISS stage I than older pts (stage I; 39% vs. 28%, stage II: 28 vs. 39%, stage III 33% vs. 33%, p<. 001, p<001, p=0.863, respectively) due primarily to a lower prevalence of high ß2m levels and low albumin levels in the younger age group. Paradoxically, the younger pts more frequently presented with higher M-component levels and Durie Salmon stage III (65% vs. 54%, p<0.001). Prevalence of other important prognostic parameters like Hb, platelet count, creatinine, calcium, CRP, LDH and bone marrow PC infiltration was similar in both groups. Younger pts had more frequently good ECOG performance status (PS) (0–2), (87% vs. 81%, p<0.01). Karyotypic abnormalities and Del 13 were similarly distributed between both cohorts. Median OS was significantly longer in young pts (median: 4.8 years vs. 3.7 years; hazard ratio (HR): 1.46; 95%, CI (1.27, 1.68); p=<0.001). Better outcome in the younger cohort was seen in all three ISS stages, independent of gender. Median OS survival was significantly longer after SDT in the young cohort (median: 49 months (mos) vs. 39 mos; HR 1.49; CI (1.27, 1.75); p<0.001). Median survival: 86 mos in young and 68 mos in older pts on HDT; this did not translate into a statistical difference (HR 1.8; CI (0.81,1.44); p=0.6). Risk estimates in a maximum likelihood analysis revealed that, apart from ISS Stage, young age followed by female sex was statistical significant for a good outcome for pts treated with SDT (Age RER: 1.43, CI (1.20, 1.70), p<0.001; Sex RER: 1.07, CI (1.02, 1.14); p < 0.013). For pts treated with HDT, only ISS Stage was found to be a risk factor, but not age or gender. Conclusions: Patients < 40 have better prognosis and survival than older patients. The most important features of young patients are low SßM, normal S. Alb, and good performance status.