Is serum cancer antigen 125 an accurate noninvasive test for diagnosing endometriosis in symptomatic women?
For women with symptoms suggestive of endometriosis, serum cancer antigen 125 (CA125) is a relatively specific (93%) and noninvasive test. It can be used to make
a presumptive diagnosis in cases for which a medical management approach is
being considered without having to perform a (gold-standard) laparoscopic
procedure to confirm. At minimum, a pelvic ultrasound to assess for other
conditions (ovarian cancer or uterine fibroids) that can raise CA125 levels
is needed. CA125 is not a sensitive test for endometriosis (52%), and therefore not helpful in ruling out the disease. Approximately half the women with histologically proven endometriosis have normal CA125 levels. (LOE = 1a-)
Hirsch M, Duffy J, Davis CJ, Plana MN, Khan KS, for the International Collaboration to Harmonise Outcomes and Measures for Endometriosis. Diagnostic accuracy of cancer antigen 125 for endometriosis:a systematic review and meta-analysis. BJOG 2016:123(11):1761-1768.