Intra-operative assessment of lymph node metastasis for colorectal carcinoma

We have evaluated the reliability of intra-operative diagnosis for lymph node metastases and assessed the clinical features affecting accuracy of the intra-operative diagnosis based on a review of operative and pathological records in 218 patients treated by curative surgery for colorectal carcinoma. The sensitivity and specificity for diagnosis of lymph node metastases was 74.2% and 54.5%, respectively. The clinically positive but pathologically negative [cN(+),pN(-)] lymph nodes group differed significantly from the cN(-),pN(-) group with respect to tumor size, gross appearance and depth of tumor invasion. In the cN(+),pN(+) group, the tumor was larger and depth of tumor invasion was more extensive than in the cN(-),pN(+) group. The postoperative survival curves showed a statistically significant difference between cN(-),pN(-) and cN(+),pN(-) groups (P<0.05). Our data suggest less than satisfactory results for the intra-operative diagnosis of lymph node metastases. Macroscopically, tumor size and gross appearance were important clinical characteristics affecting accuracy in the macroscopic diagnosis of lymph node metastases. Therefore, prophylactic lymph node dissection is recommended, regardless of intra-operative assessment of lymph node metastases.