Advances in magnetic resonance imaging of endometrial cancer

Abstract

Endometrial cancer is the most commonly diagnosed gynaecological malignancy in affluent societies [1]. It occurs most frequently in white women, with peak incidence between ages 55 and 65. Risk factors include unopposed oestrogen intake, use of tamoxifen, nulliparity, obesity, and diabetes. The incidence of endometrial cancer in the United Kingdom has increased by more than 40% between 1993 and 2007. This significant rise is predominantly due to a large increase in incidence in women aged 60–79 [1]. These trends are very similar for most European countries [2]. The increase in prevalence of obesity and decreases in fertility may partly account for the observed rapid increase in incidence and imply that endometrial cancer in postmenopausal women will become a more substantial public health problem in the future. Prognosis depends on a number of factors, including stage, depth of myometrial invasion, lymphovascular invasion, nodal status and histological grade. Depth of myometrial invasion is the single most important morphologic prognostic factor, correlating with tumour grade, lymph node metastases and overall patient survival. Incidence of lymph node metastases increases from 3% with superficial myometrial invasion (stage IA) to 46% with deep myometrial invasion (stage IB) [3]. Preoperative knowledge of these factors is crucial in tailoring the surgical approach. The histological grade can be determined at endometrial sampling, whereas depth of myometrial invasion can only be assessed preoperatively by MRI. Therefore, MRI can assist in preoperative assessment and treatment planning by accurately predicting depth of myometrial invasion, cervical stromal invasion and lymph node involvement. This information allows selection of patients for pelvic or para-aortic lymph node sampling whilst obviating the need for surgery in patients with low risk disease. MRI can also provide additional useful information such as uterine size, tumour volume, ascites and adnexal pathology which in turn may determine whether the surgical approach is transabdominal, transvaginal or laparoscopic. Lymphadenectomy in early (stage I) endometrial cancer remains a controversial issue. Two large prospective multicentre studies investigated whether pelvic lymphadenectomy could improve survival of women with endometrial cancer [4, 5]. Both studies reported no benefit in overall or recurrence free survival in the patients randomized to lymphadenectomy. Conversely, the SEPAL study [6] showed that in patients with intermediate or high risk of endometrial cancer recurrence, combined pelvic and paraaortic lymphadenectomy reduced the risk of death compared with pelvic lymphadenectomy alone. The authors acknowledged that MRI is an important factor for predicting lymph node metastasis, and in combination with tumour grade and histology could be helpful to discriminate patients with very low risk of recurrence. Therefore, E. Sala Addenbrooke’s Hospital, University Department of Radiology, Box 218, Level 5, Hills Road, Cambridge CB2 0QQ, UK e-mail: es220@radiol.cam.ac.uk