LAUSR

e19036 Background: Recent studies have shown smoking to be an independent risk factor for MDS. We aimed to assess whether smoking is associated with worse outcomes among patients (pts) with MDS at Montefiore Medical Center, Bronx, NY. Methods: Pts with MDS and chronic myelomonocytic leukemia (CMML) diagnosed between June 16, 2000 and November 13, 2020 were analyzed. Those without available tissue diagnosis or smoking history data were excluded. Descriptive statistics compared ever-smokers to non-smokers. Cox PH regression was used to analyze the risk of transformation to acute myeloid leukemia (AML) and mortality in the 2 groups and multivariable analysis (MVA) adjusted for age, sex, de novo disease and R-IPSS. Results: A total of 147 pts were identified, 109 (74.1%) had a diagnosis of de novo MDS, 89 (60.5%) had history of active or former smoking and 58 (39.5%) were non-smokers. Smokers were predominantly males (66.3%) in contrast to non-smokers (37.9%) (p=0.001). Smokers were diagnosed more frequently with high or very high risk MDS, although the difference was not statistically significant (38.1% vs 28.6%, respectively; p=0.28). TP53 mutations were numerically more frequent among smokers (24.4%), compared to non-smokers (12.8%) (p=0.16). Median follow-up time for smokers and non-smokers was 19.4 and 31.4 months, respectively. In MVA, there was a trend for increased risk of AML transformation in smokers vs non-smokers (HR 2.03, 95% CI 0.99 – 4.15; p=0.052). Smokers with MDS were found to have significantly greater mortality compared to non-smokers (HR 2.08, 95% CI, 1.22 – 3.54; p=0.007). Conclusions: Smoking was associated with worse survival among MDS pts in our cohort. Although not significantly different, the prevalence of TP53 mutations was higher among smokers. Larger studies are warranted to confirm our findings.[Table: see text]