Survival Benefit of Japanese Extended Lymphadenectomy for Clinically Node-Negative and Node-Positive Colorectal Cancers

BACKGROUND: The impact of extended lymphadenectomy for colorectal cancer is still not sufficiently clear. OBJECTIVE: The aim of the present study was to evaluate the survival benefit of extended lymphadenectomy compared with nonextended lymphadenectomy for clinically node-negative and node-positive colorectal cancers. DESIGN: The present study was a retrospective cohort study that used prospectively collected data and a propensity score matching method. SETTINGS: The present study was conducted at a single specialized colorectal surgery department. PATIENTS: Of the 1314 patients who underwent radical resection with nonextended or extended lymphadenectomy between 1988 and 2007, we included 711 and 603 patients in the cN0 and cN1/2 series. Propensity score matching was applied, and 141 and 63 pairs were extracted from the cN0 and cN1/2 series. MAIN OUTCOME MEASURES: Disease-free survival, cancer-specific survival, and overall survival of the 2 groups were calculated and compared. RESULTS: In the cN0 series, no differences were observed in the long-term outcomes between the nonextended and extended groups. In the cN1/2 series, the disease-free survival tended to be higher, and the cancer-specific survival and overall survival were significantly higher (log rank, p = 0.04, p = 0.02, and p = 0.01, respectively), but the frequency of local recurrence was significantly lower (p = 0.04) in the extended group. LIMITATIONS: The present study was limited by its nonrandomized retrospective design. CONCLUSIONS: Extended lymphadenectomy demonstrated a good inhibitory effect on the local recurrence rate and led to improved disease-free survival, cancer-specific survival, and overall survival of patients in the cN1/2 series. See Video Abstract at http://ift.tt/2EOELdt.

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