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Efficacy of Adjuvant Chemotherapy for T1-2 Stage III Colorectal Cancer
by
, ,
Hiromichi Maeda
1,*, 
Koji Oba
2,
Kosuke Kashiwabara
3,
Toru Aoyama
4,
Shuhei Mayanagi
5,
Mitsuro Kanda
6,
Michitaka Honda
7,
Masaru Muto
8,
Junichi Sakamoto
8,9,
Hisakazu Yamagishi
8 and
Takaki Yoshikawa
10 1
Department of Surgery, Kochi Medical School, Nankoku 783-8505, Japan
2
Department of Biostatistics, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
3
Data Science Office, Clinical Research Promotion Center, The University of Tokyo Hospital, Tokyo 113-8655, Japan
4
Department of Surgery, Yokohama City University, Yokohama 236-0004, Japan
5
Division of Esophageal Surgery, Shizuoka Cancer Center Hospital, Shizuoka 411-8777, Japan
6
Department of Gastroenterological Surgery, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
7
Department of Minimally Invasive Surgical and Medical Oncology, Fukushima Medical University, Fukushima 960-1247, Japan
8
Japanese Foundation for Multidisciplinary Treatment of Cancer, Tokyo 136-0071, Japan
9
Tokai Central Hospital, Kakamigahara 504-8601, Japan
10
Department of Gastric Surgery, National Cancer Center Hospital, Tokyo 104-0045, Japan
*
Author to whom correspondence should be addressed.
Cancers 2025, 17(23), 3856; https://doi.org/10.3390/cancers17233856 (registering DOI)
Submission received: 3 November 2025
/
Revised: 24 November 2025
/
Accepted: 27 November 2025
/
Published: 30 November 2025
(This article belongs to the Special Issue Chemo-Radio-Immunotherapy for Colorectal Cancer)
Simple Summary
Stage III colorectal cancer is a heterogeneous group of cases. In this study, we retrospectively examined the effects of postoperative chemotherapy on T1-2 stage III colorectal cancer, which is considered to have a favorable prognosis. A total of 604 eligible cases were extracted from a database of previous clinical trials and analyzed. After adjusting for the patient factors, the hazard ratio of relapse-free survival (RFS) was 0.79 (95% confidence interval (CI): 0.13–4.65, p = 0.79) and 0.64 (95% CI: 0.06–6.40, p = 0.70) in the 5FU and L-OHP groups, respectively. Postoperative chemotherapy showed a better prognosis than surgery alone, but the margin of improvement was minute. The results of this study are useful for decision-making regarding postoperative chemotherapy for T1-2 stage III colorectal cancer.
Abstract
Background/Objectives: This study aimed to assess the efficacy of adjuvant chemotherapy for T1-2 stage III colorectal cancer, a disease with a low recurrence rate. Methods: The efficacies of fluorouracil-based adjuvant chemotherapy (5FU group) and oxaliplatin-based adjuvant chemotherapy (L-OHP group) were assessed and compared with that of surgery alone (surgery group) using data from seven clinical trials conducted by the Japanese Foundation for Multidisciplinary Treatment of Cancer. Propensity score matching was used to compare the three groups. Direct-adjusted survival curves were delineated with consideration of treatment periods. Results: A total of 604 patients with T1-2 stage III colorectal cancer were identified. After adjusting for the patient factors, the hazard ratio of relapse-free survival (RFS) was 0.79 (95% confidence interval (CI): 0.13–4.65, p = 0.79) and 0.64 (95% CI: 0.06–6.40, p = 0.70) in the 5FU and L-OHP groups, respectively. Adjusted 5-year RFS rate was 82.8% (95% CI: 67.2–100%), 86.2% (95% CI: 74.2–100%), and 88.6% (95% CI: 74.0–100%) in the surgery, 5-FU, and L-OHP groups, respectively. Overall and disease-specific survival showed similar trends without significant differences. Conclusions: No significant improvement in prognosis was observed after adjuvant chemotherapy. The potential improvement in the 5-year RFS after adjuvant chemotherapy for resected T1-2 stage III colorectal cancer should be balanced with patient factors and adverse events.
Keywords:
colorectal cancer; adjuvant chemotherapy; T1; T2
