Screening and validation of a novel T stage-lymph node ratio classification for operable colon cancer

Jun-Peng Pei; Rui Zhang; Nan-Nan Zhang; Yong-Ji Zeng; Zhe Sun; Si-Ping Ma; Jian-Guo Zhou; Xin-Xiang Li; Jin Fan; Ji Zhu; Masanobu Abe; Zu-Bing Mei; Gang Shi; Chun-Dong Zhang

doi:10.21037/atm-21-3170

Screening and validation of a novel T stage-lymph node ratio classification for operable colon cancer

Ann Transl Med. 2021 Oct;9(20):1513. doi: 10.21037/atm-21-3170.

Authors

Jun-Peng Pei^#¹, Rui Zhang^#², Nan-Nan Zhang^#³, Yong-Ji Zeng⁴, Zhe Sun², Si-Ping Ma², Jian-Guo Zhou⁵, Xin-Xiang Li^{6

7}, Jin Fan^{8

9}, Ji Zhu^{8

9}, Masanobu Abe¹⁰, Zu-Bing Mei^{11

12}, Gang Shi², Chun-Dong Zhang^{1

13}

Affiliations

¹ Department of Gastrointestinal Surgery, The Fourth Affiliated Hospital of China Medical University, Shenyang, China.
² Department of Colorectal Surgery, Cancer Hospital of China Medical University, Liaoning Cancer Hospital and Institute, Shenyang, China.
³ State key Laboratory of Cancer Biology and National Clinical Research Center for Digestive Diseases, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
⁴ Eppley Institute for Research in Cancer, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, USA.
⁵ Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China.
⁶ Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China.
⁷ Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
⁸ Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.
⁹ Department of Oncology, Shanghai Medical College of Fudan University, Shanghai, China.
¹⁰ Division for Health Service Promotion, The University of Tokyo, Tokyo, Japan.
¹¹ Department of Anorectal Surgery, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China.
¹² Anorectal Disease Institute of Shuguang Hospital, Shanghai, China.
¹³ Department of Gastrointestinal Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.

^# Contributed equally.

Abstract

Background: Lymph node ratio (LNR) has advantages in predicting prognosis compared with American Joint Committee on Cancer (AJCC) pathological N stage. However, the prognostic value of a novel T stage-lymph node ratio (TLNR) classification for colon cancer combining LNR and pathological primary tumor stage (T stage) is currently unknown.

Methods: We included 62,294 patients with stage I-III colon cancer from the Surveillance, Epidemiology, and End Results Program as a training cohort. External validation was performed in 3,327 additional patients. A novel LNR stage was established and combined with T stage in a novel TLNR classification. Patients with similar survival were grouped according to T and LNR stages, with T1LNR1 as a reference.

Results: We developed a novel TLNR classification as follows: stages I (T1LNR1-2, T1LNR4), IIA (T1LNR3, T2LNR1-2, T3LNR1), IIB (T1LNR5, T2LNR3-4, T3LNR2, T4aLNR1), IIC (T2LNR5, T3LNR3-4, T4aLNR2, T4bLNR1), IIIA (T3LNR5, T4aLNR3-4, T4bLNR2), IIIB (T4aLNR5, T4bLNR3-4), and IIIC (T4bLNR5). In the training cohort, the novel TLNR classification had better prognostic discrimination (area under receiver operating characteristic curve, 0.621 vs. 0.608, two-sided P<0.001), superior model-fitting ability for predicting overall survival (Akaike information criteria, 561,129 vs. 562,052), and better net benefits compared with the AJCC 8^th tumor/node/metastasis classification. Similar results were found in the validation cohort for predicting both overall and disease-free survival.

Conclusions: This novel TLNR classification may provide better prognostic discrimination, model-fitting ability, and net benefits than the AJCC 8^th TNM classification, for potentially better stratification of patients with operable stage I-III colon cancer; however, further studies are required to validate the novel TLNR classification.

Keywords: Colon cancer; lymph node ratio (LNR); survival outcome; tumor/node/metastasis (TNM).