Suspected myometrial invasion on MRI is correlated with worse outcomes of fertility-preserving treatment in young women with endometrial cancer

Abstract

Abstract Purpose Myometrial invasion of endometrial cancer (EC) impairs the effectiveness of progestin-based treatment and results in high risks of disease progression and relapse. However, it is difficult to decide whether myometrial invasion exists when suspected endometrial invasion is detected on magnetic resonance imaging (MRI). This study developed an MRI-guided hysteroscopic precise en bloc resection method to actually diagnose myometrial invasion in patients with EC and suspected myometrial invasion on MRI. The fertility-preserving outcomes of patients with EC and suspected myometrial invasion on MRI but negative pathological findings after en bloc resection was also evaluated. Materials and methods EC patients with suspected myometrial invasion on MRI (n = 38) were prospectively enrolled and evaluated. Suspected myometrial invasion was identified on MR images and resected via an en bloc resection technique (resecting the endometrial lesion, basal layer, and underneath myometrium en bloc) under hysteroscopy for pathological examination. Patients with negative pathological findings received progestin-based conservative therapy. The clinical characteristics and fertility-preserving outcomes of these patients were compared with those of patients without any evidence of myometrial invasion on MRI (n = 98, reference group). Results Among patients with suspected myometrial invasion on MRI, myometrial invasion was pathologically excluded in 29 patients (non-MI group). The cumulative complete response rate was lower in the non-MI group than in the reference group at the 8th month (43.4% vs. 64.9%, P = 0.040) and was not significant at the 18th month (87.5% vs. 96.8%, P = 0.11). The 24-month cumulative relapse rate was 31.2% in the non-MI group, versus 0% in the reference group (P < 0.0001). Conclusion Myometrial invasion was pathologically confirmed in approximately one-fourth of patients with suspected myometrial invasion on MRI. However, suspected myometrial invasion on MRI with negative pathological findings was correlated with worse fertility-preserving outcomes in young women with endometrial cancer.