51 Quantitative Analysis of Plasma Cell-Free DNA: Implications for Cancer Staging and Survival in Leiomyosarcoma.

Background The prediction tool estimates overall survival in oncology. We studied the utility of circulating cell-free DNA (cfDNA) in predicting survival inpatients with intra-abdominal and retroperitoneal leiomyosarcoma (LMS) after curative-intent surgery.

Method We collected clinical data on patient demographics and tumor-specific characteristics retrospectively. Leiomyosarcoma staging was based on tumor grade (G) and TNM classification. We analyzed the correlation between circulating cell-free DNA (cfDNA) concentration and cancer status using DATAtab, and conducted survival and statistical analysis considering p-values of < 0.05 as significant.

Results Twenty-four patients (8 males and 16 females) were identified, and the mean age was 55.33 years. cfDNA was positive in all 24 samples. In this cohort, 50% were G3 and 50% were staged IIIB. The mean concentration of cfDNA was 1.67 ng/ml (0.29 – 5.48). There was a positive correlation between the concentration of cfDNA and the cancer stage, but it was not statistically significant, p = 0.74. The median disease-free survival (DFS) was 10 months (1 e 80). Disease-free survival (DFS) was not affected by high cfDNA concentrations > 32.45 ng/mL (>25% quartile) or low cfDNA concentrations 10.07 ng/mL (< 75% quartile) (p > 0.09). The DFS was also not affected by both early stages (Stages I and II) and advanced stages (stages III and IV) (p = 0.317).

Conclusions The correlation between cfDNA and DFS in LMS was not statistically significant due to a small sample size. Further studies with a longer follow-up are needed to evaluate the utility of cfDNA concentration as a predictor for LMS.