The accuracy of magnetic resonance imaging in staging of vulvar cancer: a retrospective multi-centre study.

OBJECTIVE

To retrospectively evaluate the diagnostic accuracy and clinical relevance of magnetic resonance imaging (MRI) in the management of primary and recurrent vulvar cancer and to examine the added value of contrast-enhanced MRI (CE-MRI).

METHODS

The research ethics committee waived informed consent for this study of 49 patients with vulvar cancer (36 primary and 13 recurrent) who underwent MRI before surgery at three major cancer centers from December 2003 to January 2008. CE-MRI was available for 31 patients (20 primary and 11 recurrent). MR images were retrospectively evaluated by three radiologists for tumor size and stage. Lymph nodes with a short axis >5 mm were measured and scored for contour, presence of necrosis, loss of fatty hilum, signal intensity relative to the vulvar lesion, and reader's diagnosis of lymph node metastasis. Scoring was repeated for CE-MRI. Histopathology constituted the reference standard.

RESULTS

The size of the vulvar lesion was accurately characterized on MRI in 83% of patients. Accuracy in staging of primary vulvar cancers on unenhanced MRI was 69.4% (n=36). Adding CE-MRI increased lesion detection and raised staging accuracy from 75% to 85% (n=20). For groin lymph node metastasis prediction, the ratio of the short- to the long-axis diameter and the reader's diagnosis of lymph node metastasis yielded accuracy of 85% and 87%, respectively, in groin-by-groin analysis.

CONCLUSION

MRI can be useful in accurately assessing the size of vulvar lesion and groin lymph node metastasis. CE-MRI may be of help in improving local staging.