Abstract: Background and purpose: There is a lack of serum markers for the diagnosis of ovarian cancer currently. This study aimed to investigate the clinical significance of serum sialic acid (SA) levels in patients with ovarian cancer in auxiliary diagnosis and efficacy monitoring. Methods: Enzyme reaction method was used to analyze serum SA levels and chemiluminescence was employed to detect CA125 and HE4 in participants including 194 healthy controls, 332 patients with gynecological cancer and 230 patients with benign disease. Results: The serum SA levels in patients with gynecological cancer ［584.0 (499.8, 702.5) mg/L］ were higher than those in patients with benign disease ［497.0 (454.0, 559.0) mg/L］ and healthy controls ［475.0 (443.8, 505.0) mg/L, P<0.05］. The serum SA levels in patients with ovarian malignant tumors ［675.0 (582.0, 816.0) mg/L］ were the highest. The sensitivity of the combined detection of serum SA with CA125 for ovarian malignant tumors was up to 95.17%, and the negative predictive value was 94.37%. With the improvement of the condition, the serum concentration of SA in patients with ovarian cancer gradually decreased. Conclusion: The detection of serum SA can be applied to early screening, differential diagnosis and efficacy monitoring.

Key words: Gynecological cancer, Ovarian cancer, Serum sialic acid, Enzyme reaction