Abstract 171P
Background
Patients diagnosed with pathological stage (pStage) II/III gastric cancer after curative gastrectomy are administered tegafur/gimeracil/oteracil potassium (S-1) therapy for 1 year based on the results of the ACTS-GC trial. However, the efficacy and safety of this regimen in patients aged ≥ 80 years remain unclear, because this trial excluded patients in this age group. Following gastrectomy, older patients often experience severe malnutrition, leading to systemic instability, potentially reducing treatment compliance, and causing treatment interruptions. All of these factors can compromise treatment efficacy. Here, we retrospectively surveyed the efficacy and safety of adjuvant S-1 chemotherapy in patients aged ≥ 80 years by comparing the outcomes of those who did and did not complete adjuvant S-1 chemotherapy.
Methods
We included 73 patients aged ≥ 80 years with pStage II/III gastric cancer who received adjuvant S-1 chemotherapy between November 2007 and December 2019. The completion group comprised 26 patients who completed oral administration for 1 year (eight cycles when administered in a 4-week on, 2-week off schedule), and the non-completion group comprised 47 patients who did not complete this treatment. We evaluated the efficacy using overall survival (OS) and relapse-free survival (RFS). The safety was assessed using CTCAE v5.0.
Results
The median OS was 8.0 years in the completion group and 6.2 years in the non-completion group. There was no significant difference between the two groups (p = 0.985, HR 1.007, 95% CI 0.458-2.214). The median RFS was not reached in either the completion or non-completion groups; there was also no significant difference between the groups (p = 0.847, HR 0.922, 95% CI 0.404-2.104). Hematological toxicities of any grade occurring with a frequency of 10% or higher included anemia (52.1%), leukopenia (23.3%), neutropenia (20.5%), and thrombocytopenia (19.2%). Among non-hematological toxicities, anorexia (39.7%), fatigue (27.4%), diarrhea (27.4%), and nausea (17.8%) were observed.
Conclusions
In this study, the effectiveness of completing 1 year of S-1 adjuvant chemotherapy for gastric cancer in patients aged ≥ 80 years could not be demonstrated.
Clinical trial identification
This study was reviewed and approved by Clinical Research and Ethical Review Board of the South Miyagi Medical Center. (approval #05-01, April 25th, 2023).
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.