Trisomy 8 in De Novo Acute Myeloid Leukemia Lacking MDS-Related Cytogenetics Does Not Significantly Influence Survival.

Background: The 2022 WHO and ICC classifications identify MDS-related cytogenetic abnormalities and secondary gene mutations (SM) that in de novo disease are diagnostic of myelodysplasia-related AML, which confers a poorer prognosis. While most MDS-related abnormalities overlap between the two classifications, trisomy 8 (+8) is unique to the ICC and has not been previously included as an MDS-related abnormality. In light of this, we sought to determine the prognostic significance of +8 as an MDS-related abnormality in patients with de novo AML lacking other MDS-related cytogenetics.

Methods: We identified 337 patients with de novo AML lacking MDS-related cytogenetics other than +8 and analyzed clinicopathologic outcomes, overall survival (OS), and relapse-free survival (RFS). Two groups were identified: AML with SM (n = 195, 57.9%) and AML without SM (n = 142, 42.1%). Fifty-nine (17.5%) patients had +8; 39 (66.1%) of these had at least one SM, while 20 (33.9%) did not.

Results: Among patients treated with induction or hypomethylating agents (n = 317), OS and RFS were significantly shorter in patients with SM than without (OS: p = 0.001, RFS: p = 0.0004) but not significantly different between patients with and without +8 (OS: p = 0.15, RFS: p = 0.35). Similarly, when cases were limited to those with SM (n = 179), no significant difference in OS or RFS was observed between patients with and without +8 (OS: p = 0.21, RFS: p = 0.30). There was no significant association between +8 and SM (p = 0.15).

Conclusions: In our cohort, unlike MDS-related SM, trisomy 8 does not influence OS or RFS, despite its inclusion in the ICC as an MDS-related abnormality.