Use of the concomitant serum dosage of CA 125, CA 19-9 and interleukin-6 to detect the presence of endometriosis. Results from a series of reproductive age women undergoing laparoscopic surgery for benign gynaecological conditions.

Background: Recent studies have proposed the measurement of CA 19-9 and IL-6 as an alternative to CA 125 as markers for endometriosis. This study was performed in order to verify the clinical value of serum CA 125, CA 19-9 and IL-6 levels, either by themselves or combined, in the detection of the disease.

Methods: In a prospective cohort study, serum concentrations of CA 125, CA 19-9 and IL-6 were measured in a consecutive series of 80 women of reproductive age who underwent laparoscopy for benign gynaecological pathologies.

Results: Endometriosis was documented in 45 women (stage I-II in 14 cases and stage III-IV in 31 cases). Patients with endometriosis had significantly higher levels of CA 125 than controls [23.4 IU/ml (13.3-37.6) versus 11.4 IU/ml (9.1-18.5), P < 0.001)]. Conversely, women with and without the disease were shown to have similar levels of both IL-6 pg/ml [0.6 (undetectable-1.4) versus 1.0 pg/ml (0.4-1.9), P = 0.09] and CA 19-9 [9.8 IU/ml (4.5-20.8) versus 7.4 IU/ml (2.8-11.5), P = 0.11]. The area under the receiver operating characteristics curve resulted in a statistically significant difference from the null hypothesis only for CA 125 (P < 0.001). Sensitivity and specificity of CA 125 were 27 and 97% respectively and were higher than those related to CA 19-9 and IL-6. Concomitant use of the three dosages led to a sensitivity and a specificity of 42 and 71% respectively.

Conclusions: The concomitant dosage of CA 125, CA 19-9 and IL-6 does not add significant information in respect to the CA 125 test alone in diagnosing either early or advanced stages of endometriosis.