Combined use of endometrial sample and magnetic resonance imaging in the preoperative risk-stratification of endometrial carcinomas.

OBJECTIVE: To compare two treatment strategies in women undergoing surgery for endometrial carcinoma.

DESIGN: Retrospective cohort study.

SETTING: Tertiary care center.

POPULATION: 1166 patients. Uterine biopsy/curettage was obtained in 1140 women, of whom 229 also had pelvic magnetic resonance imaging (MRI).

METHODS: We compared two strategies: (i) routine pelvic lymphadenectomy and (ii) selective pelvic lymphadenectomy for women with high-risk carcinomas as determined from preoperative histology and MRI. High-risk carcinomas included grade 1-2 endometrioid carcinomas with ≥50% myometrial invasion, grade 3 endometrioid carcinomas, and nonendometrioid carcinomas. Others were considered low-risk carcinomas.

MAIN OUTCOME MEASURES: Diagnostic indices, treatment algorithms.

RESULTS: Of the women who underwent lymphadenectomy, positive pelvic nodes were found in 2.3% of low-risk carcinomas and 18.3% of high-risk carcinomas. The combination of preoperative histology and MRI detected high-risk carcinomas with a sensitivity of 85.7%, a specificity of 75.0%, a positive predictive value of 74.4%, and a negative predictive value of 86.1%. Area under curve was 0.804. In the routine lymphadenectomy algorithm, 54.1% of lymphadenectomies were performed for low-risk carcinomas. In the selective lymphadenectomy algorithm, 14.3% of women with high-risk carcinomas did not receive lymphadenectomy. Missed positive pelvic nodes were estimated to occur in 2.1% of patients in the selective strategy. Similarly, the estimated risk for isolated para-aortic metastasis was 2.1%, regardless of treatment strategy.

CONCLUSIONS: The combination of preoperative histology and MRI is moderately sensitive and specific in detecting high-risk endometrial carcinomas. The clinical utility of the method is hampered by the relatively high proportion of high-risk cases that remain unrecognized preoperatively.