Accuracy of MRI with an endorectal coil for staging endometrial cancer.

Background: The very good results of magnetic resonance imaging (MRI) using an endorectal coil in staging prostate cancer at 1.5T suggested that this imaging technique might be able to be used to stage endometrial cancer, the most common tumor in postmenopausal women.

Purpose: To evaluate the accuracy of MRI with an endorectal surface coil for staging primary endometrial carcinoma.

Material And Methods: A total of 33 consecutive patients with biopsy-proven endometrial cancer underwent 1.5T MRI with an endorectal surface coil (eMRI) using sagittal and axial T2-weighted (T2w) turbo spin echo (TSE), axial T1 gradient echo 2D fat-saturated (fs), sagittal T1 gradient echo 3D with and without contrast enhancement (CE), and axial T1 TSE fs CE sequence. Evaluation of local tumor extension was based on the revised standard TNM classification for endometrial cancer. eMRI staging was compared with the histopathological results after surgery.

Results: A total of 33 consecutive patients underwent eMRI for staging endometrial cancer, and 21 of these underwent primary surgery. The histological stages were as follows: T1a (n = 8), T1b (n = 10), T2b (n = 2), and T3a (n = 1). Overall staging accuracy by eMRI was 71% (15 of 21). With regard to depth of myometrial invasion, eMRI correctly diagnosed stage T1a in 75% (6/8) and stage T1b in 80% (8/10). eMRI overstaged the tumor in four patients and understaged it in two.

Conclusion: eMRI is highly accurate in staging myometrial invasion. However, eMRI at 1.5T does not seem to be significantly more accurate than pelvic MRI without an endorectal coil at 1.5T for staging primary endometrial cancer. eMRI for endometrial carcinoma therefore might not meet expectations compared with the results obtained using eMRI for staging prostate cancer at 1.5T.