Diagnostic Accuracy in the Detection of Depth of Myometrial Invasion with MRI in Early-Stage Endometrial Cancer

Abstract

Objective: To study the diagnostic accuracy of pre-operative magnetic resonance imaging (MRI) in early-stage endometrial cancer with postoperative International Federation of Gynecology and Obstetrics (FIGO) staging after comprehensive staging surgery. Methods: Retrospectively, the medical records of 78 patients with early-stage endometrial cancer were analysed for the involvement of the myometrium with the tumour by diagnostic MRI and compared with histopathological reports after surgical staging. Results: The median age of patients was 56 years (ranging from 32 to 73). The median body mass index (BMI) of these women was 29 (ranging from 20 to 40). On histopathology, 72 women (92.3%) had type I endometroid endometrial cancer and 6 (7.7%) had type II carcinoma; four had papillary serous carcinoma, one had clear cell carcinoma and one had undifferentiated carcinoma. However, 43 (55.1%) had a grade I tumour, 12 (15.1%) had a grade II tumour and 17 (21.6%) had a grade III tumour. Further, 35 (44.8%) were staged laparoscopically, and 43 (55.1%) underwent open staging laparotomies. Pre-operative MRI radiological staging was carried out on all patients before surgery. However, 52 (66.7%) had stage IA disease, which suggested less than half of myometrial infiltration by tumour. Further, 21 (26.9%) showed more than half myometrial infiltration stage IB. One (1.2%) patient had stage IIIC1 disease with pelvic nodes of 2.5 × 2 cm near the obturator fossa; one (1.2%) patient had retroperitoneal nodes and para-aortic nodes of the largest 2 × 2 cm; three patients (3.8%) showed involvement of the endocervix with the tumour. Patients were histopathologically staged postoperatively according to the FIGO classification following complete staging surgery. Further, 46 (59%) were stage IA, 26 (33.3%) were stage IB, 3 (3.8%) showed stage II and 3 (3.8%) had stage IIIC1. The sensitivity for MRI for stage IA was 95.65% with (85% to 99.4%) 95% CI. The specificity was 75%, with 56.6% to 88.55 of the 95% CI. The positive likelihood ratio was 3.83, with a 95% confidence interval of 2.09 to 6.99. The sensitivity of MRI for stage IB was 69.23%, ranging from 48.2% to 85.6% of the 95% CI. The specificity was 94.23%, with 84% to 98% of the 95% CI. The positive likelihood ratio was 12, with a 95% confidence interval of 3.8 to 37. Conclusion: A pre-operative MRI contributes to the accurate staging of endometrial cancer to allow planning for the scale of the surgery. This is important for pre-operative counselling. The depth of myometrial infiltration aids in the planning of pelvic and para-aortic lymphadenectomy. Our study is comparable with the results of previous studies.