Prognostic evaluation and staging optimization of the Mayo Additive Staging System (MASS) in real world for newly diagnosed multiple myeloma patients.

OBJECTIVE: To explore the prognostic value of the Mayo Additive Staging System (MASS) in real-world patients with newly diagnosed multiple myeloma(MM).

METHODS: The clinical data of 307 patients with newly diagnosed MM from August 2015 to June 2022 were retrospectively analyzed. Survival analysis was conducted for each subgroup according to the MASS. The MASS was compared to the original staging systems to evaluate its prognostic value. Patients in the high-risk group were further stratified.

RESULTS: Patients were divided into MASS stages I (93 cases), II (91 cases), and III (123 cases), with differences in overall survival (OS) and progression-free survival (PFS) among all groups ( p  <  0.0001). Patients were grouped according to treatment regimen, age, transplant status, renal function, and bone destruction; with differences in OS and PFS among patients at each MASS stage in all subgroups ( P  ≤ 0.05). The MASS was also used for further risk stratification of patients with Mayo Myeloma Stratification and Risk-adjusted Treatment Stratification System 3.0 (mSMART3.0) and Revised International Staging System (R-ISS). Furthermore, in the MASS high-risk group, patients with scores of 2 and 3 vs 4 had OS of 23.7 and 10.1 months ( P  = 0.004), and PFS of 17.6 and 8.2 months ( P  = 0.004), respectively. Patients in the high-risk complex karyotype group not covered by SMART staging criteria had shorter OS and PFS than those in the mSMART3.0 high-risk and MASS stage III groups.

CONCLUSION: The prognostic value of the MASS in patients with MM has been verified, and has better evaluation efficiency than the SMART and R-ISS systems.