P-262 Response to perioperative chemotherapy in locally advanced gastric cancer

Abstract

Gastric cancer was the 6th most frequent tumor worldwide in 2020. The prognosis of patients with gastric and gastrooesophageal junction (GEJ) adenocarcinoma is poor. Many efforts had been made to improve these patients’ prognosis, as adjuvant chemotherapy, chemoradiation and perioperative chemotherapy. The benefit in overall survival (OS) and disease free survival (DFS) of perioperative chemotherapy was first demonstrated in MAGIC trial. FLOT trial established a superior regimen over ECF, despite that the prognosis is still poor with high recurrence rate. The authors’ aim was to characterize patients with locally advanced gastric cancer who underwent perioperative chemotherapy, their outcomes and the related factors with these outcomes, namely response to chemotherapy, resume post-operative regimen and pathological stage. Retrospective analysis of patients with locally advanced gastric cancer that underwent perioperative chemotherapy between January 1st 2016 and December 31st 2020 in a single hospital in Portugal. Clinic-pathological characteristics were accessed by reviewing medical records. A descriptive analysis was performed. Kaplan-Meier curves and Log-rank test were performed for survival analysis, SPSS®20. A total of 68 patients were included. The median age was 64-years-old (35-78), 69% (n=47) were male, 19% (n=13) had an ECOG-PS 0. As for clinical stage, 10% (n=7) were at stage Ib, 24% (n=16) stage II and 38% (n=26) stage III. 16% (n=11) were tumors of the GEJ. Regarding to histology 57% (n=39) presented intestinal type. 54% of the patients (n=37) received perioperative chemotherapy regimen with FLOT; 22% (n=15) EOX, 16% (n=11) FOLFOX and 7% (n=5) ECF. Surgery was performed in all patients, 59% (n=40) with total gastrectomy. 4% (n=3) had a complete response to preoperative chemotherapy, 22% (n=15) had a minimal response to chemotherapy, and in 43% it was not reported. 85% of the patients resume and 74% completed the initial chemotherapy regimen. With a median follow-up of 29 months (3-75), 35% (n=24) patients had an event (recurrence or death). The estimated 48 months DFS was 62%, and OS was 67%. In our study the resume of perioperative chemotherapy was associated with an improve DFS (56.5 months vs 10.4 months, p < 0.001) and OS (59 vs 13.5 months, p < .001). Patients who completed chemotherapy regimen presented a better OS (61.2 vs 40.8 months) however this increase was not statistical significant. Pathological response to chemotherapy was not associated with a better outcome. Despite that pathologic lymph node staging had impact in DFS (ypN0 51.8 months vs ypN3 14.9 months, p < .001) and OS (ypN0 53months vs ypN3 25 months, p=.001) Perioperative chemotherapy regimen was not associated with the outcome. 18% of the patients experienced adverse events grade ≥3, with neutropenia as the most common, without difference between regimens. No grade 5 adverse events occurred. Our results emphasize the importance of completing perioperative chemotherapy regimen. The retrospective nature of this study, the small sample size, and, most important, the low report in pathology, limits the assessment of the value of response to preoperative chemotherapy.