Open Access

ARTICLE

Is ypTNM staging a comparable predictor as pTNM staging for survival in non-metastatic rectal cancer after preoperative chemoradiation therapy?

JEN-PIN CHUANG^1,2,3, HSIANG-LIN TSAI^4,5, WEI-CHIH SU^4,6,7, PO-JUNG CHEN^4,6, CHING-WEN HUANG^4,5, TSUNG-KUN CHANG^4,6,7, YEN-CHENG CHEN^4,6, CHING-CHUN LI^4,8, YUNG-SUNG YEH^4,9,10, TZU-CHIEH YIN^4,5,11, JAW-YUAN WANG^{4,5,6,12,13,*}
1 Ministry of Health and Welfare, Chiayi Hospital, Chiayi, 60096, Taiwan
2 Department of Surgery, Faculty of Medicine, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
3 Department of Surgery, National Cheng Kung University Hospital, Tainan, 70101, Taiwan
4 Division of Colorectal Surgery, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
5 Department of Surgery, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
6 Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
7 Department of Surgery, Faculty of Post-Baccalaureate Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
8 Division of Colorectal Surgery, Department of Surgery, Kaohsiung Municipal Hsiaokang Hospital, Kaohsiung, 80708, Taiwan
9 Division of Trauma and Surgical Critical Care, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
10 Department of Emergency Medicine, Faculty of Post-Baccalaureate Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
11 Department of Surgery, Kaohsiung Municipal Tatung Hospital, Kaohsiung, 80145, Taiwan
12 Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
13 Center for Cancer Research, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
* Corresponding Author: JAW-YUAN WANG. Email: ,

Oncology Research https://doi.org/10.32604/or.2024.052098

Received 22 March 2024; Accepted 27 May 2024; Published online 24 June 2024

Abstract

Background: The pTNM staging system is widely recognized as the most effective prognostic indicator for cancer. The latest update of this staging system introduced a new pathological staging system (ypTNM) for patients receiving neoadjuvant chemoradiotherapy (NACRT). However, whether the prognostic value of the ypTNM staging system for rectal cancer is similar to that of the pTNM staging system remains unclear. This study was conducted to compare the ypTNM and pTNM staging systems in terms of their prognostic value for patients with nonmetastatic rectal cancer undergoing proctectomy. Material and Methods: This study was conducted at a large teaching hospital. Between January 2014 and December 2022, 542 patients with rectal cancer were analyzed (median follow-up period, 60 months; range, 6–105 months). Of them, 258 and 284 were included in the pTNM and ypTNM groups, respectively. Inverse probability of treatment weighting (IPTW) was performed to account for the effects of confounders. Cox proportional-hazards regression was performed for the between-group comparison of overall survival (OS). Results: The crude model revealed that OS was similar between the two groups (p = 0.607). After performing IPTW, we found that patients with the same ypTNM- and pTNM-classified stages had similar overall survival (hazard ratio = 1.15; 95% CI = 0.76–1.73; p = 0.5074). Conclusions: For patients with rectal cancer who have received preoperative NACRT, the prognostic value of ypTNM staging appears to be similar to that of pTNM staging, mostly because of the downstaging effect of neoadjuvant chemoradiotherapy.

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Keywords

pTNM; ypTNM; Rectal cancer; Inverse probability treatment weighting; Survival

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