Serum CA19-9 as a Predictor of Malignancy in Primary Ovarian Mucinous Tumors: A Matched Case-Control Study

BACKGROUND: This study was designed to investigate the clinical characteristics correlated with serum CA19-9 elevation in primary mucinous ovarian tumors and to evaluate the role of serum CA19-9 in predicting borderline or malignant tumors. MATERIAL/METHODS: We retrospectively identified 27 women with pathologically-confirmed primary ovarian mucinous neoplasms (16 borderline and 11 malignant), who had been preoperatively checked for serum CA19-9 and CA125 levels. The control group was established by 1:2 matching for age among all women with pathologically-confirmed benign mucinous tumors over the same time period. The associations of the serum CA19-9 elevation and clinical characteristics, including tumor pathology, were evaluated. RESULTS: Serum CA19-9 was more frequently elevated in borderline or malignant than benign tumors (57.9% vs. 16.7%, P=0.001), although the mean value of serum CA19-9 was not significantly different among histological subtypes. CA19-9 elevation was correlated with large tumor size (largest diameter ≥15 cm; p=0.028), serum CA125 elevation (p=0.006), and tumor pathology (borderline or malignant tumors; p=0.001). Other clinical characteristics, including parity, menopause, bilateral tumor involvement, and torsion were not correlated with CA19-9 elevation. Multivariate analysis revealed that tumor pathology was the only independent factor for CA19-9 elevation in primary ovarian mucinous tumors (odds ratio 3.842, 95% CI 1.277–11.558, p=0.017). Interestingly, subgroup analysis in women with normal serum CA 125 level revealed that CA19-9 was significantly correlated with borderline and malignant tumors but not with benign tumors (odds ratio 6.3, 95% CI 1.438–19.648, p=0.014). CONCLUSIONS: Serum CA19-9 can be a useful complementary marker in differentiating benign from borderline or malignant mucinous tumors in the ovaries, particularly when serum CA125 level is not elevated.