Comparison of the validity of magnetic resonance imaging and positron emission tomography/computed tomography in the preoperative evaluation of patients with uterine corpus cancer.

OBJECTIVE

To compare positron emission tomography/computed tomography (PET/CT) with magnetic resonance imaging (MRI) in the preoperative detection of primary lesions and lymph node (LN) and distant metastases in patients with uterine corpus cancer.

METHODS

The patient cohort consisted of 53 women with uterine corpus cancer who underwent preoperative workup, including both MRI and PET/CT scans, and underwent surgical staging, including pelvic and/or paraaortic LN dissection, between October 2004 and June 2007 at Asan Medical Center, Seoul, Korea. Pathologic data from surgical staging were compared with the preoperative MRI and PET/CT results. For area specific analysis, LNs were divided into paraaortic, right pelvic and left pelvic areas.

RESULTS

In detecting primary lesions, MRI and PET/CT showed no differences in sensitivity (91.5% vs. 89.4%), specificity (33.3% vs. 50.5%), accuracy (84.9% vs. 84.9%), positive predictive value (PPV) (91.5% vs. 93.3%) and negative predictive value (NPV) (33.3% vs. 37.5%). With MRI, the sensitivity, specificity, accuracy, PPV and NPV for detecting metastatic LNs on LN area-by-area analysis were 46.2%, 87.9%, 83.9%, 28.6% and 94.0%, respectively; With PET/CT, those were 69.2%, 90.3%, 88.3%, 42.9%, and 96.6%, respectively. PET/CT showed higher sensitivity, but it did not reach statistical significance (p=0.250). There were also no differences in specificity, accuracy, PPV and NPV. In detecting distant metastasis, the sensitivity, specificity, accuracy, PPV and NPV of PET/CT were 100%, 93.8%, 92.5%, 62.5% and 100%, respectively.

CONCLUSION

In patients with uterine corpus cancer, PET/CT had moderate sensitivity, specificity and accuracy in detecting primary lesions and LN metastases, indicating that this method cannot replace surgical staging. The primary benefit of PET/CT is its sensitivity in detecting distant metastases. Because of its high NPV in predicting LN metastasis, PET/CT may also have advantages in selected patients who are poor candidates for surgical staging.