OGC P04 Total Gastrectomy is associated with greater Overall Survival than Subtotal Gastrectomy in Stage III Gastric Adenocarcinoma with Signet Rings

Abstract

Abstract Background Presence of signet rings is a poor prognostic factor in advanced gastric adenocarcinoma (GAc), and is associated with lower chemo(radio)sensitivity, higher locoregional and distant recurrence rates, and lower overall survival (O.S) rates than non-signet ring gastric Ac. Incidence of signet ring GAc is increasing in Europe, Asia and USA, accounting for 35-45% of new cases of GAc. D2 lymphadenectomy and perioperative chemo(immuno)therapy enable better locoregional and systemic disease control, and reduced rate of cancer-related death in GAc. We hypothesise that total gastrectomy is associated with greater O.S than subtotal gastrectomy in signet ring positive GAc. Methods All patients who underwent elective gastrectomy for signet ring positive GAc from October 2013 - February 2023 at a single, tertiary, specialist cancer centre in the UK were included in this study. Demographic details including age, BMI, tumour staging (TNM classification), Charlson co-morbidity score, and use of neo(adjuvant) chemo(immuno)therapy were collected. Post-operative histopathology including tumour differentiation, lymphovascular invasion, lymph node yield, recurrence and survival time since surgery were collected. Statistical analyses were performed on matched data subsets using the Datatab platform, including Chi-squared, Student’s T-test and Fisher’s exact tests. Log-rank tests were performed on survival data. Results A total of 51 patients (32 male, 19 female) underwent elective total or subtotal gastrectomy for GAc with signet rings (27 total, 24 subtotal gastrectomy). There was no significant difference in mean age, BMI, tumour differentiation, nodal (N) or metastasis (M) stage between these two cohorts. A total of 14/24 (58.3%) patients underwent neoadjuvant chemo(immuno)therapy before subtotal gastrectomy, compared to 21/27 (77.8%) of patients who underwent total gastrectomy (p=0.135). Overall survival was greater among patients that underwent subtotal gastrectomy for stage I cancer (p=0.08), whereas total gastrectomy led to better survival in stage III disease (p=0.131). Conclusions This study demonstrates a trend towards greater O.S with total gastrectomy for stage III signet ring positive gastric adenocarcinoma. We suggest total gastrectomy enables better locoregional disease control in advanced cases which have higher risk of lymph node spread. The potential oncological and survival benefits of this methodology need to be weighed up against the increased morbidity and quality of life implications of total gastrectomy.