The Impact of Focal Lesions on Overall and Progression-free Survival in Multiple Myeloma.

Purpose: In this study, we aimed to reveal the incidence of ≥3 focal lesions (FLs) and analyze overall survival (OS) and progression-free survival (PFS) according to the number of FLs, as well as to identify mortality and PFS risk factors, in our newly diagnosed multiple myeloma (NDMM) patients.

Materials and methods: A total of 89 NDMM patients who underwent ¹⁸F-FDG positron emission tomography/computerized tomography (PET/CT) imaging were included in the study.

Results: While 57.3% of the patients had ≥3 FLs, 20.2% had no FL. The median OS and PFS were 55 and 43 months, respectively. The median survival time was 49 months for patients with ≥3 FLs and 101 months for patients with <3 FLs, with a statistically significant difference (P = 0.049). The median PFS was 34 months in patients with ≥3 FLs and 67 months in patients with <3 FLs; this difference was also statistically significant (P = 0.026). The difference in median survival was statistically significant, based on whether autologous stem cell transplantation (ASCT) was performed and the number of FLs (≥3 or <3) (P = 0.011). In the multivariate regression analysis, ≥3 FLs was not a predictor of mortality but was a risk factor for PFS.

Conclusion: In our study, we observed significantly worse OS and PFS in patients with ≥3 FLs at diagnosis, and it is noteworthy that the OS was worse in those patients who did not undergo ASCT. ¹⁸F-FDG PET/CT is a feasible imaging technique for the prediction of prognosis in the initial evaluation of NDMM, and we believe that consolidation with ASCT as a modifiable factor, especially in patients with ≥3 FLs, will lead to a more favorable prognosis.