Objective: To evaluate the usefulness of serum assays for CA 125 to detect recurrent endometrial carcinoma.
Methods: Two hundred sixty-six patients were studied with 1101 post-treatment assays. Patients were categorized as low, medium, or high risk based on surgical-pathologic findings. CA 125 values were analyzed with respect to each patient's disease status.
Results: Serial CA 125 levels were elevated (greater than 35 U/mL) in 19 of 33 patients (58%) with recurrent disease. Among 236 surgically treated patients, 97 (41.1%), 42 (17.8%), and 97 (41.1%) were considered low, medium, and high risk, respectively. None of the low-risk and only two (4.7%) of the medium-risk patients developed recurrent disease. One of the latter patients was detected based on an elevated CA 125 level alone. Twenty-seven (27.8%) of the high-risk patients developed recurrent disease, 23 of whom had elevated pre-treatment CA 125. Fifteen of 16 (94%) with recurrent disease had an elevated CA 125 level. Nine of 12 patients with papillary serous carcinoma experienced recurrence; eight of these nine had elevated CA 125 levels at diagnosis and recurrence, in contrast to only one patient with a normal pre-treatment level (P = .018). False elevations were noted in 13 patients, 12 of whom had received radiation therapy.
Conclusions: CA 125, if elevated at diagnosis of endometrial carcinoma, is an important marker for recurrent disease. The use of serial CA 125 assays is most beneficial in diagnosing recurrence in a high-risk population, including patients with papillary serous carcinomas. False elevations may occur following radiation therapy.