Efficacy and safety of conversion therapy with Fluorouracil, Leucovorin, Oxaliplatin and Docetaxel (FLOT) in unresectable advanced gastric cancer

Objectives: FLOT protocol has recently been applied in the neoadjuvant treatment for locally advanced, resectable gastric or gastroesophageal junction adenocarcinoma, while the application of FLOT regimen in conversion therapy of unresectable gastric cancer, especially in comparing the efficacy of FLOT regimen with traditional S-1 and oxaliplatin (SOX) regimen, remains to be explored. We performed a retrospective analysis to investigate the efficacy and safety of FLOT regimen in conversion therapy of unresectable advanced gastric cancer. Methods: : A total of 49 patients with unresectable advanced gastric cancer who received conversion therapy of SOX and FLOT was retrospectively analyzed from January 2019 to June 2020. The patients were divided into two groups: SOX (n=23) and FLOT (n=26). Clinical efficacy, adverse reactions, surgical safety and short-time survival of patients was compared between the two groups. Results: : The follow-up time was 24-42 months up to June 2022. No significant difference was found between the baseline data of SOX group and FLOT group. After conversion chemotherapy, ORR in the FLOT group was significantly higher than that in SOX group (80.8% vs. 47.8%, p=0.016). There were significant differences in surgical conversion rate (52.2% vs. 80.8%, P=0.033) and TRG (P=0.041) between SOX group and FLOT group. The incidence of adverse events (AEs) was 100%. The majority of the patients had grade 1 to 2, and there was no significant difference between the two groups in the incidence of serious adverse reactions of grade 3 to 4. The operative time (213.75±26.41 min vs. 214.91±30.68 min, P=0.914), intraoperative blood loss (263.33±43.24 ml vs. 276.90±81.02 ml, P=0.535), R0 resection rate (83.3% vs. 90.5%, p=0.960) and overall postoperative complication rate (41.7% vs. 38.1%, p=1.000) was not statistically different between the two groups. There were significant differences in 2-year overall survival (OS) rate and overall median survival time between SOX and FLOT group. (2-year OS: 29.8% vs. 61.1%, overall median survival time: 16 months vs. 30 months; P=0.045) Conclusion: FLOT regimen is safe and effective in the treatment of locally unresectable gastric cancer. Compared with SOX regimen, FLOT regimen in conversion therapy can improve the surgical conversion rate, R0 resection rate and overall survival time of patients.