Does Dose Reduction Compromise Pathological Response in Perioperative Gastric Cancer Chemotherapy? A Real-World Observational Analysis of FLOT and EOX

Abstract

Introduction: Standard of care of locally advanced gastric and Type III GE junction tumors is perioperative chemotherapy followed by radical surgery. There is clear evidence of FLOT outperforming other regimens in current literature. However, there is scarce data on dose modifications of various regimens and its effect on pathological tumor regression grade. Material and Methods: This is retrospective study from a single institution between 2022 and 2024. Patients diagnosed with locally advanced gastric and Type III GE junction tumors, who underwent perioperative chemotherapy followed by radical surgery were included. Data including histopathological report, tumor regression grade following perioperative chemotherapy, chemotherapy regimen, chemotherapy dose intensity, and completion of chemotherapy, were collected from the medical records. Results: Forty-one patients diagnosed as locally advanced gastric or GE junction cancers. Twenty patients (61%) received 3 cycles of perioperative EOX and 16 patients (39%) received 4 cycles of FLOT. Pathological complete response was higher in the EOX group than FLOT (75% vs 25%). Among patients receiving <80% of planned chemotherapy dose, none of the FLOT patients achieved TRG 0, whereas 36.4% of EOX patients did. Among patients receiving ≥80% of planned dose, the rate of TRG 0 was similar between regimens: EOX: 35.7%, FLOT: 30%. On logistic regression analysis, dose intensity ≥80% demonstrated higher odds of achieving major tumor regression. Distal tumors and dose intensity >80% increased the odds of improved tumor regression. Conclusion: EOX regimen numerically showed more pCR rates than FLOT regimen. Dose density of >80% and distal tumors were predictors of better TRG scores.