Predictive factors for the presence of malignant transformation of pelvic endometriosis.

OBJECTIVES: To determine predictive factors for the presence of malignant transformation in ovarian endometriotic cysts. STUDY DESIGN: This was an IRB approved, case control study analyzing patient data from 2004 to 2013. Pathology database records were searched to identify patients with benign endometrioma and ovarian carcinoma arising in the background of endometriosis. Inclusion criteria required each patient to have a preoperative diagnosis of adnexal mass and no other findings concerning for malignancy. Patient clinical records were queried for preoperative symptoms, serum CA125 levels and radiologic findings. Pathologic data were collected including histology, tumor grade and stage. RESULTS: A total of 138 patients met inclusion criteria; 42 women with ovarian cancer arising in the background of endometriosis and 96 women with benign endometrioma. Women diagnosed with ovarian cancer were significantly older than women with endometriosis (53.6 vs. 39.2 years). There was no difference in presence of symptoms between the two groups. Women with malignant tumors were found to have significantly larger cysts (14 cm vs. 7.5 cm; p<0.0001) that were more often multilocular (45.7% vs. 12.2%; p<0.0001), and contained solid components (77.1% vs. 14.5%; p<0.0001). Among patients that were observed prior to surgery there was a significant difference in the change in size of the mass over time with 4.2 cm increase for cases vs. 1.0 cm increase for controls (p=0.02). Multiple logistic regression analysis indicated that for every 5 years increase in age there was an adjusted OR of 2.17 (p=0.003). An age of 49 years or greater had an 80.6% sensitivity (95% CI: 62.5-92.5%) and an 82.9% specificity (95% CI: 67.9-92.8%) for malignancy, and solid component on imaging had an adjusted OR of 23.7 (p<0.0001). Serum CA125 levels tended to be higher in patients with malignant tumors but did not reach statistical significance with a mean of 204.9 vs. 66.9 (p=0.1). CONCLUSIONS: Significant predictors for malignant transformation of endometriosis include cyst characteristics and age. Women above the age of 49 with multilocular cysts and solid components are at high risk for malignant transformation of endometriosis. Serum CA125 level is not a significant predictor of malignant transformation.