Abstract: Modefied Method of Methylene Blue Injection into the Superior Rectal Artery Improves LymphNode Harvest in Rectal Cancer SpecimensJianpei LIU, Yong HUANG, Zongheng ZHENG,Weiping GUO, HongboWEICorresponding author: HongboWEI, E-mail: drwhb@21cn.comDepartment of Gastrointestinal Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510630, ChinaAbstract Objective: To explore the feasibility of improving lymph node harvest in rectal cancer specimens by modified methodof methylene blue injection into the superior rectal artery. Methods: Between August 2009 and December 2009, 20 rectal cancerpatients treated in the Third Affiliated Hospital of Sun Yat-sen University were managed by traditional method of palpation andmodified method of methylene blue injection into the superior rectal artery. The lymph nodes were picked up in three regions accordingto Dukes staging. Data of lymph node harvest were analyzed by paired t test and χ2test. Results: The total number of detected lymphnodes in traditional method group was 194. Another 201 lymph nodes were added to final harvest with modified method of methyleneblue. The average lymph nodes detected by traditional method and modified method were 9.7 ± 0.7 and 19.8 ± 0.9, respectively. In themodified method group, 57.2 % lymph nodes were smaller than 5mm. The number of patients with positive lymph nodes was 4 and 8 intraditional method group and modified method group, respectively, with significant differences ( P = 0.0455 ). Conclusion: Modifiedmethod of methylene blue injection into the superior rectal artery is simple, safe and cheap. This method is helpful for improvement oflymph node harvest and accurate pathological staging.Keywords Methylene blue; Rectal neoplasm; Lymph node