The following is a summary of “Comparison of prognostic scores according to WHO classification in 170 patients with advanced mastocytosis and C-finding treated with midostaurin,” published in the September 2024 issue of Hematology by Heiblig et al.

Advanced systemic mastocytosis (AdvSM) includes various subtypes and is linked to poor patient outcomes. While midostaurin was the first tyrosine kinase inhibitor approved for patients with AdvSM, long-lasting responses are often limited. Existing scoring systems like the Mutation-Adjusted Risk Score (MARS), the International Prognostic Scoring System for mastocytosis (IPSM), and the Global Prognostic Score for Systemic Mastocytosis (GPSM) help assess outcomes, but understanding prognosis within each AdvSM subtype is crucial. 

Researchers conducted a retrospective study evaluating how well different prognostic scores predict outcomes based on AdvSM subtypes using Harrell’s concordance index. 

They conducted a nationwide retrospective study using the French mastocytosis reference center’s registry, including all midostaurin-treated patients with C findings. A total of 170 patients were identified: 46 with aggressive SM (ASM), 11 with mast cell leukemia (MCL), and 113 with SM associated with hematological neoplasm (SM-AHN). 

The result showed that all risk scores had improved overall survival (OS) predictive value when combined with the AdvSM subtype. The best predictor was the adjusted MARS with a C-index of 0.689, followed by GPSM (C-index = 0.677) and IPSM (C-index = 0.618). In multivariable analysis, both MARS stratification and the AdvSM subtype were prognostic for OS. There were 5 patient subgroups, identified with varying median OS: 9.9 months for MCL, 24 months for intermediate/high-risk SM-AHN, 33 months for intermediate/high-risk ASM, 58 months for low-risk SM-AHN, and not reached for low-risk ASM (P<0.001). 

Investigators concluded that the AdvSM subtype and MARS are the most reliable predictors of OSl in patients with AdvSM. These insights emphasize the need for personalized management strategies based on individual risk factors and disease subtypes.

Source: onlinelibrary.wiley.com/doi/full/10.1002/ajh.27478