Study on sentinel lymph node biopsy by carbon nanoparticles and 99mTc sulfur colloid for rectal cancer TONG Han-xing, ZHAO Gang, LU Wei, et al. Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai200032,China Corresponding author: LU Wei-qi，E-mail: weiqi_lu@eastday.com Abstract Objective To evaluate the feasibility of sentinel lymph node （SLN）biopsy (SLNB) after carbon nanoparticles (CNP) and 99mTc sulfur colloid (TSC) injected in rectal cancer patients. Methods Twenty-eight patients underwent radical resection of a primary rectal cancer between October 2004 and September 2006 at Zhongshan Hospital of Fudan University were considered for inclusion. During resection, SLN mapping was performed with CNP and TSC. All lymph nodes were stained with HE. SLNs with negative routine HE staining were further analyzed with cytokratin 20 immunohistochemistical（CK20-IHC）staining. Results Fifty-two nodes ( 2 per patient) were identified as SLNs in 27 of 28 patients. In 18 of 27 patients, with SLNs and nonSLNs proven negative by HE staining, 5 patients showed positive SLNS by CK20-IHC. The accuracy rating and the false-negative rate of HE staining for SLN were 92.59% and 10% respectively. Conclusion SLNB by CNP and TSC for rectal cancer is feasible. Rectal cancer SLNB should apply different mapping method based on the lesion position.