Lateral lymph-node dissection for rectal cancer: meta-analysis of all 944 cases undergoing surgery during 1975-2004.

BACKGROUND Colorectal cancer is the third most common cancer and leading cause of cancer-related death in Japan. One of the major problems in rectal cancer surgery is local recurrence. Pelvic sidewall dissection (PSD) has the potential to reduce local recurrence. PATIENTS AND METHODS This study included all 994 patients with rectal cancer who underwent curative surgery from January 1975 until December 2004, at the Kurume University Hospital in Fukuoka, Japan. The patients were analyzed to determine whether lateral lymph node (LLN) metastasis correlates with clinicopathological factors, and to determine a diagnostic tool based on magnetic resonance imaging (MRI) findings. RESULTS The rate of positive LLNs in patients who underwent PSD was 7.5% in the upper rectum, and 14.5% in the lower rectum. Logistic regression analysis disclosed that perirectal lymph nodes metastasis was associated with an increased incidence of positive LLNs and had a greater hazard ratio. Positive LLNs were frequently found to be located along the internal iliac artery (47 patients; 89%) or around the oburator vessels and nerve (17 patients; 32%). MRI has become a promising diagnostic tool in patients with rectal cancer including LLN estimation. CONCLUSION We speculate that PSD may be a good candidate as an effective strategy for lower rectal cancer. In further studies, it is important to investigate the validity of PSD for its potential clinical use in lower rectal cancer therapy and prognosis.