Objective: We sought to determine the clinical utility of preoperative CA 125 measurement in determining the need for lymphadenectomy in patients with endometrial carcinoma.
Study design: A prospective nonrandomized study was performed over a 2-year period. Patients referred with the diagnosis of endometrial carcinoma had CA 125 levels determined before surgical staging. Operative findings were then correlated with preoperative CA 125 values. Standard statistical calculations were used to determine sensitivity, specificity, positive predictive value, and false-positive and false-negative rates. The Student t test was used to determine differences between mean values.
Results: Either a CA 125 level of >20 U/mL or a grade 3 tumor or both of these correctly predicted 87% of patients requiring surgical staging. In patients with a preoperative diagnosis of stage I, grade 1 or 2 tumors, a CA 125 level of >20 U/mL correctly identified 75% (9/12) of patients requiring lymphadenectomy compared with only 50% (6/12) identified when a CA 125 level of >35 U/mL was used. Two of 16 low-risk patients with preoperative grade 1 tumors and CA 125 levels of <20 U/mL had occult extrauterine disease at surgery.
Conclusion: Measurement of preoperative CA 125 is a clinically useful test in endometrial cancer. CA 125 levels of >35 U/mL strongly predicted extrauterine disease but lacked sensitivity in identifying patients needing staging. Either a CA 125 level of >20 U/mL or a grade 3 tumor or both of these correctly identified 75% to 87% of patients requiring lymphadenectomy. Until more data are collected, abdominal hysterectomy should be the procedure of choice for patients with grade 1 tumors and CA 125 levels of <20 U/mL.