Abstract Background The standard adjuvant chemotherapy regimen for stage III gastric cancer is docetaxel plus S‐1 (DS) based on the results of the START‐II trials. However, in clinical practice some patients could not continue this intensive doublet chemotherapy because of limited tolerability. This study aimed to assess the practical feasibility of DS and elucidate the predictive factors for the completion of adjuvant DS therapy. Methods Data from consecutive patients who underwent radical gastrectomy between 2018 and 2021 and were diagnosed with histopathologically confirmed stage III gastric cancer were retrospectively collected. First, the completion rate and adverse effects of DS were assessed. Second, the association between DS incompletion and patient backgrounds including body weight, skeletal muscle index (SMI), and intramuscular adipose content (IMAC) were examined. Results Of 87 patients, 59 patients (67.8%) completed DS and dose reduction was required in 18 patients (20.6%). Neutropenia of grade 3 or higher was the most common hematological toxicity observed (17.2%). The most frequent nonhematological toxicity of grade 3 or higher was fatigue (6.9%), followed by diarrhea (5.7%), nausea (4.5%), and anorexia (4.5%). In a multivariate analysis, low SMI ( p = 0.005) and high IMAC ( p = 0.004) were significant risk factors for DS incompletion. Conclusions DS adjuvant chemotherapy after radical gastrectomy for pathological stage III gastric cancer is acceptable, even in clinical practice, with respect to completion and toxicity. Additionally, the body composition factors such as SMI and IMAC might be useful in predicting incompletion of DS. These findings will help us to preoperatively select patients for DS.

Feasibility and predictive factors on the completion of docetaxel plus S‐1 adjuvant chemotherapy in pathological stage III gastric cancer