Significance of CT in the detection of regional lymph node metastases in colorectal carcinoma

PURPOSE: For preoperative staging of colorectal cancer a CT scan is frequently performed. This report examines the sensitivity of CT for regional lymph node metastasis of colorectal cancer using different criteria. MATERIALS AND METHODS: Preoperative CT scans of 153 patients with colorectal cancer were analyzed using different criteria for N1. The results were then compared to the postoperative histological findings. RESULTS: For N1 = lymph nodes (LN) > 1 cm the sensitivity was 47%. For N1 = LN > 1 cm or an increased number of LN < 1 cm the sensitivity was 71%. In patients with a primary tumor seen on CT, sensitivity rose to 87%. DISCUSSION: Evidence of regional nodal metastatic disease is only relevant for rectal cancer, colon polyps, and for locally excised tumors when considering present surgical concepts for the treatment of colorectal cancer. In these cases CT analysis using the broadened criteria for N1 proposes a valuable argument regarding possible preoperative radiotherapy or an operative revision.