P094 Correlation of circulating cell-free DNA and Disease-Free Survival in Liposarcoma – A Prospective Cohort Study

Background: Survival analysis predicts survival outcomes and identifies related factors associated with an increased likelihood of an event. The analysis of disease-free survival (DFS) provides a better understanding of the patient’s condition and recurrence-related characteristics. In this study, we examine the effect of circulating cell-free DNA (cfDNA) as predictive or prognostic factors on survival in patients diagnosed with liposarcoma and who underwent curative-intent surgical treatment.

Material and methods: Clinical data related to other prognostic factors (patient demographics, liposarcoma subtype, tumour size or volume, tumour grade, TNM classification, and ECOG performance status) were collected retrospectively. Blood samples were collected prospectively from liposarcoma patients at different points in a surgical timeline. Circulating cell-free DNA (cfDNA) was isolated from plasma, quantified, and sequenced. Survival analysis was performed to investigate prognostic factors of disease-free survival in liposarcoma. Hazard ratio (HR) and its 95% CIs were used to estimate the prognostic value of cfDNA.

Results (For Surgical Trial Proposals fill in 'the Feasibility', for Surgical Trial in Progress fill in the 'Current status'): Thirty-two patients (14 males and 18 females) were identified, and the mean age of this cohort was 61.2 years. There were two cases of ALT, nine cases of WDLPS, and twenty-one cases of DDLPS. Of the cohort, 68.75% (22/32) were primary, and 31.25% (10/32) were recurrence. cfDNA was positive in all 32 samples. There was no statistical difference between the cfDNA concentration and all three histology subtypes (p= 0.545) and disease status (primary and recurrent) (p = 0.904). The mean concentration of cfDNA was 2.259 ng/μl (0.626 – 11.500), and it was set as the cut-off for high-concentration cfDNA. The median DFS for high and low-concentration cfDNA was four and five years, respectively. cfDNA concentration higher than the mean had a lower 5-year DFS (HR 1.632, 95% CI 0.4237 - 6.284) than a lower concentration cfDNA (HR 0.6128, 95% CI 0.5191 – 2.360). DFS is not associated with other covariates (age, gender, tumour volume and weight).

Conclusions (For Surgical Trial in Progress and Surgical Trial Proposals fill in 'NA'): The correlation between cfDNA and DFS was not statistically significant. However, the data set and sample size were small. Further studies are suggested to analyse the role of these prognostic factors in predicting disease-free survival.