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. 2023 Apr 30;7(6):922-931.
doi: 10.1002/ags3.12687. eCollection 2023 Nov.

Exploratory randomized phase II trial for optimizing treatment dosage and duration of adjuvant S-1 plus oxaliplatin in patients with stage III colon cancer: YCOG1402 (SOAP trial)

Yusuke Suwa  1 , Jun Watanabe  1 , Hirokazu Suwa  2 , Mayumi Ozawa  3 , Masashi Momiyama  4 , Atsushi Ishibe  3 , Kotaro Nagamine  5 , Shigeru Yamagishi  6 , Mitsuyoshi Ota  7 , Tadao Fukushima  8 , Hitoshi Sekido  9 , Yusuke Saigusa  10 , Itaru Endo  2
Affiliations

Exploratory randomized phase II trial for optimizing treatment dosage and duration of adjuvant S-1 plus oxaliplatin in patients with stage III colon cancer: YCOG1402 (SOAP trial)

Yusuke Suwa et al. Ann Gastroenterol Surg. .

Abstract

Introduction: Conventionally, the recommended duration of adjuvant chemotherapy of colon cancer had been 6 months. The IDEA Collaboration suggested that shortening capecitabin and oxaliplatin (CAPOX) adjuvant chemotherapy may be possible. S-1 and oxaliplatin (SOX) treatment is standard treatment in metastatic colorectal cancer in Japan. The aim of this study was to optimize treatment dosage and duration of adjuvant SOX in stage III colon cancer.

Methods: This trial was as open-label multi-center randomized phase II study. Patients with stage III colon cancer were randomly assigned to 3 months or 6 months of adjuvant SOX treatment in different doses: 130 mg/m2 (3 months) or 100 mg/m2 (6 months) of oxaliplatin. The primary endpoint was 3-year disease-free survival (DFS) and the null hypothesis for the primary endpoint was that the 3-year DFS was ≤72% in each arm and was tested with a one-sided significance level of 10%.

Results: Eighty-two patients were assigned to the 6 months arm and 81 to the 3 months arm. The 3-year DFS was 75.0% (80% CI 67.95-80.72, p = 0.282) in the 6 months arm and 76.9% (80% CI 70.1-82.38, p = 0.171) in the 3 months arm. Treatment completion rate and relative dose intensity (RDI) were higher in 3 months than 6 months arm. The adverse events (AE) were similar in both arms.

Conclusions: The 3-year DFS was not significantly superior to null hypothesis in both 3 months and 6 months arms for the stage III colon cancer. Primary endpoint was not achieved. The SOX regimen was not feasible in long-term outcomes.

Keywords: SOX; adjuvant treatment; and S‐1; colorectal cancer; oxaliplatin.

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Conflict of interest statement

The authors declare no conflicts of interest for this article. The authors, Jun Watanabe and Itaru Endo, are editorial members of Annals of Gastroenterological Surgery.

Figures

FIGURE 1
FIGURE 1
The Peri‐neuropathy Questionnaire (PNQ).
FIGURE 2
FIGURE 2
CONSORT Flow Diagram.
FIGURE 3
FIGURE 3
(A) The Kaplan–Meier curve of disease‐free survival in 6 months and 3 months arm. (B) The Kaplan–Meier curve of overall survival in 6 months and 3 months arm.
FIGURE 4
FIGURE 4
(A) The motor peri‐neuropathy had no difference between 6 months and 3 months arms during treatment and post treatment on PNQ. (B) The sensory peri‐neuropathy had no difference between 3 months and 6 months arms during treatment and post treatment on PNQ.
See this image and copyright information in PMC

References

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