OGBN P16 Endoscopic surveillance allows prediction of burden of early signet ring cell carcinoma in Hereditary Diffuse Gastric Cancer syndrome

Abstract

Abstract Background Hereditary diffuse gastric cancer (HDGC) syndrome is commonly linked to CDH1 germline pathogenic variants (PV) and carries a high lifetime risk of diffuse gastric cancer (DGC). Definitive treatment remains prophylactic total gastrectomy (PTG). However, endoscopic surveillance can be offered to inform decision-making around surgery, although the optimal time for treatment escalation remains unclear. This study aims to establish whether histopathological assessment of endoscopic biopsies can predict burden of early signet ring cell (SRC) carcinoma on PTG specimens. Methods We performed a retrospective review of prospectively collected data on endoscopic and surgical histopathologic results from CDH1 PV carriers who underwent PTG at Addenbrooke’s Hospital between January 2006 and May 2023. Targeted and systematic Cambridge protocol biopsies were performed. Patients with confirmed DGC (stage 2 or higher) at baseline endoscopy were excluded. Pearson correlation was performed to assess the relationship between number of SRC foci on endoscopy and surgical specimens. Results 46 patients underwent PTG with median of 3 pre-operative surveillance endoscopies over 22 months. Final stage was pT1aN0M0 in 41 patients and pT0N0M0 in 5 patients. The number of SRC foci on PTG specimens ranged from 0 to 273. There was a strong correlation between number of SRC foci on gastrectomy specimens and from targeted and random biopsies when evaluated separately and together for last 2 and all endoscopies. The strongest correlation was seen with total number of SRC foci on random biopsies for last 2 endoscopies (r=0.738, p-value<0.001). Random biopsies outperformed targeted biopsies in prediction of early SRC burden. Conclusions Endoscopic surveillance with systematic targeted and random biopsies by expert endoscopists within a dedicated specialist service provides useful information to estimate the burden of early SRCC. Low number of SRC foci at last two endoscopies indicate scarce gastric neoplastic involvement.