Prospective assessment of EUS criteria for lymphadenopathy associated with rectal cancer

BackgroundThere are few data that assess the accuracy of echo characteristics for predicting lymph-node (LN) metastases in patients with rectal cancer.ObjectiveTo identify nodal echo characteristics and size predictive of malignant infiltration and to determine if any combination of standard nodal criteria has sufficient predictive value to preclude FNA.DesignProspective uncontrolled study.SettingTertiary-referral hospital.PatientsSeventy-six patients (68% men) with untreated rectal cancer; 52 had visualized LNs.InterventionEUS-guided FNA.Main Outcome MeasurementsEvaluation of perirectal nodal morphology accuracy that corresponds to malignant cytology and identification of echo criteria, including LN size, to have sufficient predictive value to predict malignancy.ResultsForty-three of 52 patients (83%) underwent FNA of a visualized LN. Nodal hypoechogenicity and short-axis length ≥5 mm were factors independently predictive of malignancy. The number of malignant nodal echo features per node did not distinguish benign from malignant pathology, except when all 4 features were present. Only 68% of malignant LN had ≥3 echo characteristics. An optimum LN short-axis or long-axis length cutoff value of 6 mm or 9 mm were 90% and 95% specific, respectively, for the presence of malignancy by receiver operating characteristic analysis.LimitationsFNA was performed in a subset of identified LNs.ConclusionsNodal echo features alone are often inadequate to establish the presence of locoregional metastatic disease by EUS. These data support the value of FNA to confirm the presence of malignancy in place of relying on imaging criteria.