Evaluation of the sensitivity, specificity, positive and negative predictive values of preoperative magnetic resonance imaging for staging endometrial cancer. A prospective study of 100 cases at the Dorset Cancer Centre

Objectives: The objectives were to evaluate the sensitivity and specificity of preoperative magnetic resonance imaging (MRI) in predicting myometrial invasion and disease stage in cases of endometrial carcinoma. Study design: Prospective analytic study in 100 sequential cases of endometrial carcinoma referred to the Dorset Cancer Centre between January 1999 and July 2004. The study included 100 women with histologically proven endometrial malignancy, the mean age of the studied population being 68.6 years ±2S.D. The preoperative MRI findings were compared with final surgical and histological staging; the latter was taken as the gold standard. The main outcome measures were the sensitivity and specificity of preoperative MRI for staging endometrial cancer. Results: A total of 100 consecutive cases of endometrial cancer were analysed, of which 62 cases were classified as stage Ia/Ib (early disease) by histology. MRI accurately predicted the degree of invasion in 54 cases and overestimated in 8, giving a sensitivity of 87% and specificity of 90%. In stage Ic disease the sensitivity and specificity of MRI were 56 and 86%, respectively. However, MRI showed significantly reduced sensitivity for predicting stage II endometrial cancer at 19% but was found to be both sensitive and specific for predicting advanced endometrial cancer (stages III and IV); the sensitivity and specificity were 100 and 99%, respectively. Conclusions: The accuracy of MRI scanning in predicting early and advanced endometrial disease is very good, but there is reduced accuracy with stage Ic and stage II disease. MRI is a valuable imaging modality in the preoperative assessment of cases of endometrial cancer.