Diagnostic Validity of Serum and Peritoneal CA125, CA19.9 and plasma Cell-Free Nuclear DNA (ccf nDNA) as Biomarkers of Pelvic Endometriosis: A Case Control Study

Abstract

Endometriosis, an estrogen dependent gynecologic disorder, affects 10% to 15% women of reproductive age from all ethnic and social groups. Endometriosis is defined as the presence of endometrial-like tissue outside the uterine cavity. The degree of endometriosis is staged according to the classification system of the American Society of Reproductive Medicine into minimal, mild, moderate, and severe disease (Fassbender et al., 2013). Endometriosis can be associated with infertility and/or pain symptoms, including cyclic pelvic pain, dysmenorrhea, dyspareunia, dysuria, and dyschezia (Sinaii et al., 2008). Endometriosis-associated pain can be caused by peritoneal inflammation, adhesion formation, and specific innervations of endometriotic lesions and is correlated with the presence of deep infiltrating disease (Fassbender et al., 2013). Transvaginal ultrasound (TVU) is an adequate diagnostic method to detect ovarian endometriotic cysts but does not rule out peritoneal endometriosis, endometriosis-associated adhesions, or some locations of deep infiltrating - 145 - endometriosis (DIE) (Kennedy et al., 2005). Furthermore, routine vaginal examination alone may be insufficient to detect endometriosis before laparoscopy (Hudelist et al., 2011). The gold standard for diagnosis of endometriosis is laparoscopic inspection with histologic confirmation after retrieval of lesions (Kennedy et al., 2005). However, laparoscopy is a surgical procedure with rare but significant potential risks for the patients (Slack et al., 2007). The diagnosis of endometriosis is difficult because of non-specific symptoms, late presentation and the use of laparoscopy, which is limited by available funding, the surgeon’s experience, and human error, including missing non-specific lesions. The development of a simple blood test as a marker for screening patients at risk for endometriosis would reduce the number of unnecessary interventions and would therefore be very useful (Fassbender et al., 2013).