Evaluation of the prognostic impact of pathologic tumor regression grade on patients with colorectal cancer after preoperative chemoradiotherapy

Eiichi Nakao; Michitaka Honda; Noriyuki Uesugi; Mitsumasa Osakabe; Ayaka Sato; Yukitoshi Todate; Mizunori Yaegashi; Yoshinao Takano; Akira Sasaki; Koji Kono; Tamotsu Sugai

doi:10.1002/jso.27662

Evaluation of the prognostic impact of pathologic tumor regression grade on patients with colorectal cancer after preoperative chemoradiotherapy

J Surg Oncol. 2024 May 1. doi: 10.1002/jso.27662. Online ahead of print.

Authors

Eiichi Nakao^{1

2

3}, Michitaka Honda^{2

3}, Noriyuki Uesugi^{1

4}, Mitsumasa Osakabe⁴, Ayaka Sato⁴, Yukitoshi Todate^{2

3}, Mizunori Yaegashi⁵, Yoshinao Takano³, Akira Sasaki⁵, Koji Kono⁶, Tamotsu Sugai^{1

4}

Affiliations

¹ Diagnostic Pathology Center, Southern Tohoku General Hospital, Koriyama, Fukushima, Japan.
² Department of Minimally Invasive Surgical and Medical Oncology, Fukushima Medical University, Fukushima, Japan.
³ Division of Surgery, Southern Tohoku General Hospital, Koriyama, Fukushima, Japan.
⁴ Department of Molecular Diagnostic Pathology, School of Medicine, Iwate Medical University, Yahaba, Japan.
⁵ Department of Surgery, School of Medicine, Iwate Medical University, Yahaba, Japan.
⁶ Department of Gastrointestinal Surgery, Fukushima Medical University, Fukushima, Japan.

PMID: 38691656
DOI: 10.1002/jso.27662

Abstract

Background: The prognostic value of the pathological response to preoperative chemoradiotherapy (CRT) in rectal cancer (RC) remains unknown.

Objectives: We aimed to assess the predictive value of the response to CRT that was derived from an evaluation of the histological findings (whole-section vs. representative-section sampling) and attempted to determine an objective cut-off value for the tumor regression grade (TRG).

Methods: We examined the association of the TRG with the outcomes (recurrence-free survival [RFS] and overall survival [OS]) of 78 patients with RC. Patients with RC treated with preoperative CRT were divided into development (30 cases) and validation (48 cases) cohorts. The TRG was classified as grades I (Ia, Ib), II, and III. The cut-off value was determined by receiver operating characteristic (ROC) curve analysis.

Results: The TRG determined from whole-section sampling versus representative-section sampling was more strongly correlated with patient survival. We found that in both cohorts, patients with a cut-off value of <73% had a poor prognosis. Finally, the cut-off value was found to be an independent predictive factor in both univariate and multivariate analysis.

Conclusions: The TRG that was used to evaluate patients with RC who underwent preoperative CRT was an independent prognostic factor for outcome.

Keywords: chemoradiotherapy; cut‐off value; prognosis; rectal cancer; tumor regression grade.