High accuracy of multislices computed tomography (MSCT) for para-aortic lymph node metastases from gastric cancer: a prospective single-center study.

Background: The purpose of this study is to analyze the diagnostic accuracy of MSCT in the identification of para-aortic lymph node metastases from gastric cancer.

Methods: A total of 92 consecutive patients with primary gastric cancer were prospectively submitted to preoperative MSCT staging according to a standard protocol in the period 2003-2010. All diagnostic procedures were performed by dedicated radiologists who were unaware of the final pathological nodal status. Subsequently all patients underwent potentially curative (R0) resection with extended lymphadenectomy plus para-aortic nodal dissection. Lymph node mapping in different stations and retrieval of single lymph nodes were performed by the surgeon on the fresh specimen and then submitted for pathological examination. Clinical, radiological, and pathological data were prospectively stored on database.

Results: A median number of 47 (range: 18-114) total lymph nodes and 7 (range: 3-29) para-aortic lymph nodes were removed. In 13 of 92 included patients (14%), histological examination demonstrated para-aortic nodal metastases; MSCT was correctly positive in 11 of these cases (sensitivity: 85%). In 79 patients para-aortic nodes were not involved, and MSCT resulted correctly negative in 75 of these patients (specificity: 95%). Positive (PPV) and negative (NPV) predictive values were 73 and 97%, with a global accuracy of 93%.

Conclusions: MSCT performed according to a standard protocol by dedicated radiologists demonstrated high accuracy in preoperative identification of para-aortic nodal metastases from gastric cancer. These results may be useful in planning surgical approach or during clinical staging before neoadjuvant chemotherapy.