Larger short-axis length of lymph nodes predicts malignant involvement

LETTERS TO THE EDITOR Larger short-axis length of lymph nodes predicts malignant involvement To the Editor: We read with interest the article by Gleeson et al1 on EUS-guided FNA of regional lymph nodes (LNs) in patients with cholangiocarcinoma. EUS identified LNs in all 47 patients, and EUS-FNA confirmed metastases in 9 of the 70 LNs (18%), which precluded 8 patients (17%) from liver transplantation. Identified LNs, irrespective of malignant involvement, were typically oval and geographic in shape, of mixed echogenicity, and with a hypoechoic border. Although the authors concluded that no morphology or EUS features of identified LNs correlated with nodal malignancy, we believe that a simple EUS feature might predict nodal malignancy before histologic confirmation. LN metastasis in patients with resected cholangiocarcinoma indicates poor survival. If nodal metastasis can be preoperatively detected, ineffective surgery can be avoided.2 EUS is highly suited to detect and assess LNs in patients with various malignancies.3 EUS features of malignant LNs are reported to be the hypoechoic homogeneous structure, distinct margins, round shape, and size larger than 1 cm, but most authors agree that these features may be less reliable.3-6 Although contrastenhanced EUS,2 EUS-FNA,3,4 and EUS elastography6 can be superior to conventional EUS in predicting nodal malignancy, these special methods are not available in all hospitals. Although Gleeson et al1 and others2,6 demonstrated that the size (long-axis length) and long-axis/short-axis length ratio (roundness) of LNs were not associated with nodal malignancy, the short-axis length of LNs itself has not been highlighted. We analyzed 1359 dissected LNs of resected gastric cancers and disclosed that the short-axis length of LNs was more closely related to nodal metastasis than the long-axis length and long-axis/short-axis length ratio of LNs.7 On EUS, LNs with a larger short-axis length were also more likely to be malignant.3,5 If the larger short-axis length of LNs predicts nodal malignancy, this simple feature would be valuable. Mitsunobu Matsushita, MD Kazushige Uchida, MD Akiyoshi Nishio, MD Kazuichi Okazaki, MD Third Department of Internal Medicine Kansai Medical University Osaka, Japan www.giejournal.org

REFERENCES 1. Gleeson FC, Rajan E, Levy MJ, et al. EUS-guided FNA of regional lymph nodes in patients with unresectable hilar cholangiocarcinoma. Gastrointest Endosc 2008;67:438-43. 2. Kanamori A, Hirooka Y, Itoh A, et al. Usefulness of contrast-enhanced endoscopic ultrasonography in the differentiation between malignant and benign lymphadenopathy. Am J Gastroenterol 2006;101:45-51. 3. Chen VK, Eloubeidi MA. Endoscopic ultrasound-guided fine needle aspiration is superior to lymph node echofeatures: a prospective evaluation of mediastinal and peri-intestinal lymphadenopathy. Am J Gastroenterol 2004;99:628-33. 4. Jacobson BC, Hirota WK, Goldstein JL, et al. The role of EUS for evaluation of mediastinal adenopathy. Gastrointest Endosc 2003;58:819-21. 5. Kinney TP, Waxman I. Does size really matter? Am J Gastroenterol 2004; 99:634-5. 6. Saftoiu A, Vilmann P, Ciurea T, et al. Dynamic analysis of EUS used for the differentiation of benign and malignant lymph nodes. Gastrointest Endosc 2007;66:291-300. 7. Matsushita M, Hajiro K, Suzaki T, et al. Histopathological assessment of lymph node metastasis in patients with gastric cancer. Hepatogastroenterology 1995;42:861-6. doi:10.1016/j.gie.2008.06.043

Response: We read Dr Matsushita’s summary and comments with great interest. He raises a relevant point with regard to the importance of lymph node short-axis dimension as a morphological factor predictive of nodal malignant infiltration. The standard 4 EUS criteria predictive of malignancy were initially characterized by Catalano et al,1 highlighting that lymph node size O10 mm was the most important feature. In many EUS and lymph node pathological studies to date, the lymph node long axis has been the dimension of choice.2-4 Faigel5 demonstrated that lymph node size (long axis) differentiated benign from malignant nodes within the thorax but not for pancreaticobiliary malignancies. As no criterion alone is predictive of malignancy, Vazquez-Sequeiros et al6 suggested that the development of modified EUS lymph node criteria would more accurately correlate morphology with either cytology or histology. That study specifically used a width O5 mm to suggest malignancy. Peng et al7 have recently highlighted that the short axis was the only measured factor indicative of malignancy, yet van Delden et al,8 in a laparoscopic US study, determined that, although the short axis was associated with malignancy, it lacked sufficient specificity to predict malignant infiltration. We recently prospectively assessed EUS criteria for lymphadenopathy associated with rectal cancer. Our study9 highlighted that nodal hypoechogenicity and short axis length R 5 mm were factors independently predictive of malignancy. Optimum lymph node, short-axis or long-axis length cut-off values of 6 mm or 9 mm were 90% and 95% specific for the presence of malignancy by receiver operating curve Volume 69, No. 2 : 2009 GASTROINTESTINAL ENDOSCOPY 387