Objective: To compare fat clearance and fat lucidification in the examination of rectal cancer specimen, and to study the distribution pattern of lymph nodes in rectal cancer specimen.
Method: Between January 2007 and December 2007, sixty-four cases undergone total mesorectal excision were divided into two groups. The fat clearance technique was used to examine the specimens in one group, while fat lucidification was used in the other. The total number and the number of metastatic lymph nodes between two groups were compared, as well as the time for processing specimens and that for dissecting the lymph nodes.
Results: An average of 37.4 lymph nodes were detected with fat clearance, in which 3.3 lymph nodes were metastatic; while an average of 36.2 nodes were detected with fat lucidification, in which 3.2 were metastatic. There were no significant differences in either the total number or the number of metastatic lymph nodes. The time for processing specimens in the fat lucidification group was 28 hours, while in the fat clearance group was 72 hours. The time for specimen processing was significantly shorter in the fat lucidification group (P<0.05). The mean time for dissecting lymph nodes in the fat clearance group was 2.1 hours, while in the fat lucidification group was 2.0 hours, the difference was not statistically significant.
Conclusion: When processing rectal cancer specimens with the fat lucidification technique can result in the similar number of lymph nodes compared to the fat clearance technique, with significantly shorter specimen processing time. The spatial position of the lymph nodes is better preserved using the fat lucidification technique, which may help study the distribution pattern of the normal and metastatic lymph nodes.