Concurrent versus sandwich treatment in adjuvant treatment in high risk operated gastric cancer: A single center experience

Purpose: In this study we compared postoperative early vs sandwich chemoradiotherapy in operated stage IIA-IIIC gastric cancer patients in terms of effectiveness and outcome. Methods: The data of 201 gastric cancer patients treated in the same center between December 2006 and June 2017 were retrospectively evaluated. One hundred forty nine patients who were eligible for the study criteria were divided into two groups according to the postoperative treatment modality. The first group included 85 patients who were given chemoradiotherapy simultaneously (ETG) and the second group icluded 64 patients who received sandwich (chemotherapychemoradiotherapy-chemotherapy) (STG) treatment. Overall survival (OS) and disease-free survival (DFS) were evaluated as primary endpoints. Results: The median follow-up time for all patient groups was 26.7 months (1.3-136.5 months). Adjuvant chemotherapy and radiotherapy were initiated concurrently in patients receiving concomitant therapy. Half of the planned chemotherapy, then chemoradiotherapy and then the remaining chemotherapy treatments were given to the sandwich treatment group. A total of 50.4 Gy radiotherapy was given to the concurrent chemoradiotherapy group and a total of 45 Gy radiotherapy to the group receiving the sandwich treatment. OS was 30.6 months (23.7-37.5) in all groups, 30.4 months (23.7-35.0) in concurrent therapy (ETG) and 35.6 months (26.3-45) in sandwich therapy (STG) (p=0.73). DFS was 26.6 months (21.3-32.0) in all groups and 24.5 months (18.1-31.0) in the group receiving ETG, 32.5 months (22.242.8) in STG. (p=0.46). The most common grade 3 and above toxicities were; acute upper gastrointestinal toxicity (19.1% in ETG vs. 9.0% in STG, p=0.01) and hematological toxicity (31.8% in ETG vs. 13.9% in STG; p=0.002). Early cessation of treatment was similar in both groups. In multivariate analysis, female gender (p=0.01), stage III disease, grade III disease were seen as negative predictive factors for overall survival. In DFS multivariate analysis, there was no difference between the groups in terms of gender, T stage, N stage, and AJCC stage. Conclusion: In this study, superiority of sandwich treatment over concurrent treatment was observed in patients with operated stage IIB-IIIC gastric cancer, but the difference was not statistically significant. If this study is performed in larger patient series, the difference of sandwich treatment may become meaningful.