Published in:
01-07-2011 | Original Article
Lymph node ratio is a powerful prognostic index in patients with stage III distal rectal cancer: a Japanese multicenter study
Authors:
Hirotoshi Kobayashi, Hidetaka Mochizuki, Tomoyuki Kato, Takeo Mori, Shingo Kameoka, Kazuo Shirouzu, Yukio Saito, Masahiko Watanabe, Takayuki Morita, Jin-ichi Hida, Masashi Ueno, Masato Ono, Masamichi Yasuno, Kenichi Sugihara, Study Group for Rectal Cancer Surgery of the Japanese Society for Cancer of the Colon and Rectum
Published in:
International Journal of Colorectal Disease
|
Issue 7/2011
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Abstract
Purpose
The present study aims to define the prognostic impact of the lymph node ratio (LNR) in patients with stage III distal rectal cancer.
Methods
We analyzed data from 501 patients who underwent curative resection (total mesorectal excision, TME) for stage III distal rectal cancer at 12 institutions between 1991 and 1998. Patients were divided into four groups according to quartiles based on LNR.
Results
Among the 501 patients, 381 underwent TME with pelvic sidewall dissection (PSD). The median numbers of lymph nodes retrieved with and without PSD were 45 and 17, respectively (P < 0.0001). Forty-nine patients with lymph node retrieved less than 12 were excluded from further analyses. Among various clinicopathological parameters, univariate analysis identified age (P = 0.0059), histological grade (P < 0.0001), depth of tumor invasion (P = 0.0003), and number of positive nodes (P < 0.0001) and LNR (P < 0.0001) as prognostic factors. The Cox proportional hazards model revealed that age (P = 0.014), histological grade (P < 0.0001), depth of tumor invasion (P = 0.0002), and LNR (group 3, P = 0.0012; group 4, P < 0.0001) were independent prognostic factors. When the American Joint Committee on Cancer (AJCC) seventh staging system was added as a covariate, both AJCC stage (P < 0.0001) and LNR (P < 0.0001) were independent prognostic factors.
Conclusions
Adding the LNR concept to the AJCC cancer staging system will improve accuracy in evaluating the nodal status of distal rectal cancer.