751 Correlation between tumor markers and tumor burden in advanced epithelial ovarian cancer

Introduction/Background*

The aim of this study was to correlate the serum concentrations of tumor markers HE4 and CA125 with the tumor burden evaluated through the volumetric parameters of FDG-PET/CT FDG in patients with advanced epithelial ovarian cancer (EOC) before primary treatment.

Methodology

Sixty-six patients with advanced stage high grade serous ovarian carcinoma (HGSOC) or undifferentiated carcinoma (UOC) were included. Serum HE4, serum CA125 and FDG PET/CT were performed before primary treatment. Volumes of interest (VOIs) were delimited on every pathological uptake in PET images. Whole-body metabolic tumor volume (wbMTV) and total lesion glycolysis (wbTLG) were calculated as the sum of every single VOI value. SUVmax thresholds were set at 40% and 50%. Four VOIs subgroups were defined for analysis: carcinomatosis, retroperitoneal, supradiaphragmatic and metastases. MTV and TLG values were calculated for each of them. The associations between these parameters and serum tumor markers were assessed through Pearson and Spearman tests.

Result(s)*

When correlating wbMTV and wbTLG with both CA125 and HE4, significant associations were found. The strongest correlation was observed between HE4 and wbMTV40% (r=0.61, p<0.001). Peritoneal carcinomatosis MTV exhibited a statistically significant correlation with both tumor markers. Pearson’s correlation coefficient was 0.61 (p<0.0001) between HE4 and MTV40% and 0,29 (p=0.02) between CA125 and MTV40%. Neither the retroperitoneal nor the supradiaphragmatic or metastatic disease assessed by MTV and TLG showed any correlation with these tumor markers.

Conclusion*

Peritoneal tumor burden measured by FDG PET/CT volumetric parameters correlates better with HE4 than with CA125 in patients with advanced epithelial ovarian cancer. These results support the increasing utility of HE4 to improve the stratification of these patients in clinical practice