Adding cancer antigen 125 screening to gray scale sonography for predicting specific diagnosis of benign adnexal masses in premenopausal women: is it worthwhile?

OBJECTIVES: The purpose of this study was to assess whether a single determination of the serum cancer antigen 125 (CA-125) level provides additional information to sonography for specific diagnosis of benign adnexal masses in premenopausal women.

METHODS: We conducted a retrospective study comprising 1058 premenopausal women (mean age, 34.8 years) with histologically proven benign adnexal masses. All women had undergone transvaginal sonography and serum CA-125 determination within 1 week before surgery and tumor removal. According to "pattern recognition" analysis, a presumptive diagnosis was provided on gray scale transvaginal sonography for all masses. Positive and negative likelihood ratios were calculated for gray scale sonography and gray scale sonography plus CA-125.

RESULTS: Eighty-five women had bilateral masses (1143 masses analyzed). In 7 women with bilateral masses, the histologic diagnoses of the masses were discordant and were excluded. Histologic diagnoses were as follows: endometrioma, n = 452; dermoid cyst, n = 180; serous cyst, n = 158; hemorrhagic cyst, n = 119; mucinous cyst, n = 54; hydrosalpinx, n = 37; and other, n = 109. The median CA-125 level was significantly higher in endometrioma (71.9 IU/mL; range: 5-2620 IU/mL) and hydrosalpinx (59.2 IU/mL; range, 5-601 IU/mL) compared to all other tumor types (P < .001). The CA-125 level was 35 IU/mL or higher in 74% of endometriomas, 58% of hydrosalpinges, 34% of hemorrhagic cysts, 18% of mucinous cysts, 14% of dermoid cysts, and 8% of serous cysts. The positive and negative likelihood ratios for sonography and sonography plus CA-125 (335 IU/mL) for each kind of tumor were not statistically different except for endometrioma, for which the positive likelihood ratio for sonography plus CA-125 (55.0; 95% confidence interval, 27.5-109.9) was significantly higher than for sonography alone (19.2; 95% confidence interval, 13.6-27.1).

CONCLUSIONS: Cancer antigen 125 screening does not add useful information for specific diagnosis of benign adnexal tumors, except for endometrioma. An elevated CA-125 level significantly increases the probability of such a lesion.