Use of tumor markers to distinguish endometriosis-related ovarian neoplasms from ovarian endometrioma

Objective Only few studies have focused on tumor markers used in the preoperative diagnosis of endometriosis-related ovarian neoplasms, and previous studies have only assessed serum CA125 levels. This study investigated the significance of preoperative tumor markers and clinical characteristics in distinguishing endometriosis-related ovarian neoplasms from ovarian endometrioma. Methods A case-control study was conducted on 283 women who were diagnosed with confirmed pathology with endometriosis-related ovarian neoplasms (n=21) and ovarian endometrioma (n=262) at a single institution from April 2008 to April 2018. The serum CA125, CA19-9, carcinoembryogenic antigen (CEA), sialyl Lewis-x antigen (SLX), and lactate dehydrogenase (LDH) levels, age, tumor size, and the presence of mural nodule of the patients were analyzed. Results Patients with endometriosis-related ovarian neoplasms were more likely to be older (48 (range, 26-81) vs 39 (range, 22-68) years, P<0.001), have higher levels of CA19-9 (42 vs 19 U/mL, P=0.013), CEA (1.3 vs 0.84 ng/mL, P=0.007), SLX (41 vs 33 U/mL, P=0.050), and LDH (189 vs 166 U/mL, P<0.001) and larger tumor size (79 vs 55 mm, P=0.001), and present with mural nodule (85.7 vs 4.5 %, P<0.001) than those with ovarian endometrioma. The CA125 levels did not significantly differ between the two groups. The area under the curve for each factor was as follows: CA19-9 level, 0.672 (95% CI 0.52 to 0.83; P=0.013); CEA level, 0.725 (95% CI 0.58 to 0.87; P=0.007); SLX level, 0.670 (95% CI 0.53 to 0.84; P=0.050); LDH level, 0.800 (95% CI 0.70 to 0.90; P<0.001); age, 0.775 (95% CI 0.65 to 0.90; P<0.001); and tumor size, 0.709 (95% CI 0.56 to 0.86; P=0.001). Age was a better marker than CA19-9, CEA, and SLX levels according to the receiver operating characteristic curve analysis. The optimal cut-off values for age and tumor size were 47 years and 80 mm, respectively. Conclusions The assessment of serum CA19-9, CEA, SLX, and LDH levels may be a useful tool in the preoperative evaluation to differentiate between endometriosis-related ovarian neoplasms and ovarian endometrioma.