A prospective blinded comparison of the accuracy of transvaginal sonography and frozen section in the assessment of myometrial invasion in endometrial cancer.

OBJECTIVE

To compare the accuracy of preoperative transvaginal sonography (TVS) and intraoperative frozen section (FS) in the assessment of myometrial invasion of endometrial carcinoma, having the definitive histological examination as gold standard.

METHODS

155 consecutive women (mean age 63 years, range 32-88) diagnosed as having endometrial carcinoma were prospectively evaluated at TVS in order to preoperatively stage the disease. All the patients subsequently underwent complete surgical staging including total abdominal hysterectomy, bilateral oophorectomy, pelvic and lumboaortic lymphadenectomy. After removal of the uterus, intraoperative FS was performed by pathologists with special interest in gynaecologic oncology in a predefined, standardized manner. Sensitivity, specificity, positive and negative predictive values were calculated for both modalities as regards neoplastic invasion of the myometrium.

RESULTS

Overall, 131 women (84.5%) had an endometrioid adenocarcinoma, 8 (5.2%) an adenosquamos carcinoma, 7 (4.5%) a serous papillary carcinoma, 4 (2.6%) a clear cell carcinoma, 3 (1.9%) a mixed type carcinoma, 1 (0.6%) a carcinosarcoma, and 1 (0.6%) a mesodermal mixed malignant tumor. Sensitivity, specificity, positive and negative predictive values and accuracy for TVS in the evaluation of myometrial infiltration were: 75%, 89%, 86%, 79% and 81%. Corresponding features for FS were: 92%, 92%, 89%, 94% and 92%. The diagnostic performance of FS was higher than that of TVS (Cohen's K value: 0.841; p<0.0005).

CONCLUSION

Intraoperative FS performed better than preoperative TVS in the assessment of myometrial invasion by endometrial cancer. Despite being time consuming, FS can be regarded as a useful modality in order to decide whether to perform lymphadenectomy in cases with poor visualization of the endometrium at TVS and when TVS gives inconclusive results.