Optimal Timing of Total Gastrectomy to Prevent Diffuse Gastric Cancer in Individuals With Pathogenic Variants in CDH1

Points to consider regarding prophylactic total gastrectomy in germline CDH1 variant carriers

Pathogenic germline CDH1 mutation confers high risk for developing diffuse gastric and lobular breast cancers in asymptomatic carriers. In these individuals, the estimated gastric cancer risk at 80 years of age is up to 70% for males and 56% for females. Due to this high-risk predisposition, prophylactic total gastrectomy is considered a unique life-saving approach in germline CDH1 carriers, as endoscopy often fails to detect early stage diffuse gastric carcinoma. However, surgical indication is controversial in some clinical contexts, with possible contraindications. This review discusses points against and in favor of a more aggressive surgical approach for consideration during the decision-making process.

Laparoscopic prophylactic total gastrectomy with limited lymphadenectomy for CDH1 gene carriers

BACKGROUND

CDH1 gene mutations are the leading etiology of hereditary diffuse gastric cancer with cumulative lifetime risk ranging up to 83%. Prophylactic total gastrectomy (PTG) is, therefore, recommended for CDH1 carriers. A laparoscopic approach may reduce operative risk versus an open operation, thus leading more patients with CDH1 mutations to pursue PTG prior to cancer development. However, more experience and oncologic outcome data are needed for a laparoscopic approach and indicated lymphadenectomy.

METHODS

A retrospective descriptive cohort study of adult patients with CDH1 mutations who underwent laparoscopic PTG with D1 lymphadenectomy between 2012 and 2022 was conducted at a single institution. All patients had preoperative EGD screening, and those with visible tumor lesions on surveillance EGD were excluded and not considered prophylactic. Demographics, family history, pathology, and operative course were obtained. Outcomes included complications, readmission, and postoperative weight change.

RESULTS

Among 23 patients, median age was 48 years (IQR 37, 53) and 15 (65%) were female. Family history for gastric and/or lobular breast cancer was present in 22 (96%) patients. The median [IQR] time from positive genetic testing to PTG was 347 days [140, 625]. Pathologic evaluation showed five (22%) patients with foci of gastric cancer on pre-operative EGD biopsies, 10 (44%) in resected stomach specimens. All lymph nodes were negative. To address early postoperative complications, EJ anastomotic technique changed from EEA to GIA over the course of the study and feeding jejunostomy was no longer placed during PTG with minimal change in postoperative weight loss.

CONCLUSIONS

This is the largest series, spanning 10 years at a single institution, dedicated solely to a laparoscopic approach for risk-reducing PTG. A laparoscopic approach with limited lymphadenectomy resulted in acceptable surgical and oncologic outcomes. Despite no visible cancer, over half of our patients had foci of early gastric cancer. Therefore, CDH1 carriers should consider laparoscopic PTG.

Factors associated with detection of hereditary diffuse gastric cancer on endoscopy in individuals with germline CDH1 mutations

BACKGROUND AND AIMS

Individuals with germline pathogenic CDH1 variants have a high risk of hereditary diffuse gastric cancer. The sensitivity of EGD in detecting signet ring cell carcinoma (SRCC) in this population is low. We aimed to identify endoscopic findings and biopsy practices associated with detection of SRCC.

METHODS

This retrospective cohort included individuals with a germline pathogenic/likely pathogenic CDH1 variant undergoing at least 1 EGD at Memorial Sloan Kettering Cancer Center between January 1, 2006, and March 25, 2022. The primary outcome was detection of SRCC on EGD. Findings on gastrectomy were also assessed. The study included periods before and after implementation of the Cambridge protocol for endoscopic surveillance, allowing for assessment of a spectrum of biopsy practices.

RESULTS

Ninety-eight CDH1 patients underwent at least 1 EGD at our institution. SRCC was detected in 20 (20%) individuals on EGD overall and in 50 (86%) of the 58 patients undergoing gastrectomy. Most SRCC foci were detected in the gastric cardia/fundus (EGD, 50%; gastrectomy, 62%) and body/transition zone (EGD, 60%; gastrectomy, 62%). Biopsy results of gastric pale mucosal areas were associated with detection of SRCC (P < .01). The total number of biopsy samples taken on EGD was associated with increased detection of SRCC (P = .01), with 43% detected when ≥40 samples were taken.

CONCLUSIONS

Targeted biopsy sampling of gastric pale mucosal areas and increasing number of biopsy samples taken on EGD were associated with detection of SRCC. SRCC foci were mostly detected in the proximal stomach, supporting updated endoscopic surveillance guidelines. Further studies are needed to refine endoscopic protocols to improve SRCC detection in this high-risk population.

Transversal Perspectives of Integrative Oncology Care in Gastric and Lobular Breast Cancer

The occurrence of gastric cancer has been associated with an increased risk of lobular breast tumors in a subset of patients harboring selected germline mutations. Among all, the germline alteration of the gene coding for E-Cadherin (CDH1) was associated with an increased risk of gastric cancer diffuse-histotype and lobular breast cancer. However, the risk assessment of breast neoplasms and the role of multiple prophylactic procedures in these patients has never been systematically addressed. In addition, the performance of the common screening procedures for lobular breast cancer like mammography is suboptimal. Therefore, recalling the need for a better articulation of the patient-centered strategies of surveillance for individuals with germline CDH1 and other similar alterations, to offer comprehensive approaches for prevention, early diagnosis, and treatment. Accordingly, this chapter aims to discuss the value and the role of integrated oncological care in the era of oncology sub-specializations. Additionally, it sheds light on how the harmonization across the health providers can enhance patient care in this setting.

Hereditary diffuse gastric cancer (HDGC). An overview

It is estimated that up to 10% of gastric carcinomas show familial aggregation. In contrast, around 1-3 % (approximately 33,000 yearly) are genuinely hereditary. Hereditary diffuse gastric cancer (HDGC) is a rare malignancy characterized by autosomal dominant inheritance of pathological variants of the CDH1 and CTNNA1 genes encoding the adhesion molecules E-cadherin and α-catenin, respectively. The multifocal nature of the disease and the difficulty of visualizing precursor lesions by endoscopy underscore the need to be aware of this malignancy as surgical prevention can be fully protective. Here, we provide an overview of the main epidemiological, clinical, genetic, and pathological features of HDGC, as well as updated guidelines for its diagnosis, genetic testing, counseling, surveillance, and management. We conclude that HDGC is a rare, highly penetrant disease that is difficult to diagnose and manage, so it is necessary to correctly identify it to offer patients and their families' adequate management following the recommendations of the IGCL. A critical point is identifying a mutation in HDGC families to determine whether unaffected relatives are at risk for cancer.

Grossing of Gastrointestinal Specimens: Best Practices and Current Controversies

The proper handling of the gross specimen is imperative, as it is the most important first step in providing excellent patient care. Our diagnoses depend on the correct description and submission of tissue sections for histologic analysis. A logical and problem-solving approach to handling the gross specimen is presented.

CDH1 Gene Mutation Hereditary Diffuse Gastric Cancer Outcomes: Analysis of a Large Cohort, Systematic Review of Endoscopic Surveillance, and Secondary Cancer Risk Postulation

Simple Summary

Some patients carry a mutated copy of the CDH1 gene that can lead to a very rare form of hereditary gastric cancer called signet-ring cell adenocarcinoma (SRCC). SRCCs rarely form visible tumors prior to spreading. Hence, patients are recommended to have prophylactic gastrectomies at a young age. Many patients wish to avoid surgery and thus have regular checks with upper endoscopy with biopsies to rule out cancer. Further, these patients may also be at risk of other cancers beyond the already known breast cancer risks, but this is not known. In this study, we show that despite systematic biopsy protocols, many early cancers might be missed on endoscopy. Therefore, patients should not rely on endoscopy to delay surgery. These patients may also be at increased risk of colorectal SRCC, which has very poor survival outcomes. To confirm this, we need a central database that captures outcomes for this patient population.

Abstract

Hereditary diffuse gastric cancer (HDGC) is a rare signet-ring cell adenocarcinoma (SRCC) linked to CDH1 (E-cadherin) inactivating germline mutations, and increasingly other gene mutations. Female CDH1 mutation carriers have additional risk of lobular breast cancer. Risk management includes prophylactic total gastrectomy (PTG). The utility of endoscopic surveillance is unclear, as early disease lacks macroscopic lesions. The current systematic biopsy protocols have unknown efficacy, and other secondary cancer risks are postulated. We conducted a retrospective study of consecutive asymptomatic HDGC patients undergoing PTG, detailing endoscopic, pathologic, and outcome results. A systematic review compared endoscopic biopsy foci detection via random sampling versus Cambridge Protocol against PTG findings. A population-level secondary-cancer-risk postulation among sporadic gastric SRCC patients was completed using the Surveillance, Epidemiology, and End Results database. Of 97 patients, 67 underwent PTG, with 25% having foci detection on random endoscopic biopsy despite 75% having foci on final pathology. There was no improvement in the endoscopic detection rate by Cambridge Protocol. The postulated hazard ratio among sporadic gastric SRCC patients for a secondary colorectal SRCC was three-fold higher, relative to conventional adenocarcinoma patients. Overall, HDGC patients should not rely on endoscopic surveillance to delay PTG, and may have secondary SRCC risks. A definitive determination of actual risk requires collaborative patient outcome data banking.

BRAZILIAN GASTRIC CANCER ASSOCIATION GUIDELINES (PART 2): UPDATE ON TREATMENT

BACKGROUND

: The II Brazilian Consensus on Gastric Cancer of the Brazilian Gastric Cancer Association BGCA (Part 1) was recently published. On this occasion, countless specialists working in the treatment of this disease expressed their opinion in the face of the statements presented.

AIM

: To present the BGCA Guidelines (Part 2) regarding indications for surgical treatment, operative techniques, extension of resection and multimodal treatment.

METHODS

To formulate these guidelines, the authors carried out an extensive and current review regarding each declaration present in the II Consensus, using the Medline/PubMed, Cochrane Library and SciELO databases initially with the following descriptors: gastric cancer, gastrectomy, lymphadenectomy, multimodal treatment. In addition, each statement was classified according to the level of evidence and degree of recommendation.

RESULTS

: Of the 43 statements present in this study, 11 (25,6%) were classified with level of evidence A, 20 (46,5%) B and 12 (27,9%) C. Regarding the degree of recommendation, 18 (41,9%) statements obtained grade of recommendation 1, 14 (32,6%) 2a, 10 (23,3%) 2b e one (2,3%) 3.

CONCLUSION

: The guidelines complement of the guidelines presented here allows surgeons and oncologists who work to combat gastric cancer to offer the best possible treatment, according to the local conditions available.

Genetic Gastric Cancer Risk Syndromes

Purpose of review

Gastric cancer is a leading cause of cancer death in the world. Between 1% and 3% of cases are associated with specific genetic cancer risk syndromes. The purpose of this article is to review the latest insights, as well as gaps in knowledge, regarding some of the most common hereditary gastric cancer syndromes: hereditary diffuse gastric cancer (HDGC), gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS), Lynch syndrome, the adenomatous polyposis syndromes, and the hamartomatous polyposis syndromes.

Recent findings

Patients carrying pathogenic variants in CDH1, but not meeting clinical criteria for HDGC, are increasingly being identified thanks to multigene panel testing; their absence from previous analyses overestimated gastric cancer penetrance. GAPPS is a recently described hereditary gastric cancer syndrome associated with specific point mutations in the promoter 1B region of the APC gene.

Summary

Risk of gastric cancer is highest among carriers of pathogenic variants in CDH1, with cumulative incidences approximately 40% and 30% for men and women, respectively. Mutations associated with Lynch syndrome and adenomatous polyposis syndromes confer greatest risk for gastric cancer in East Asian populations. Risk of gastric cancer in GAPPS and hamartomatous polyposis syndromes is difficult to estimate due to their rarity, but mutation status likely determines risk. Future research is needed to more precisely define risk of gastric cancer in these syndromes, so strategies for screening and prophylactic gastrectomy can be optimized.

Barriers and facilitators to CDH1 carriers contemplating or undergoing prophylactic total gastrectomy

Hereditary diffuse gastric cancer (HDGC) is an inherited cancer syndrome associated with high lifetime risk of diffuse-type gastric cancer. Current guidelines recommend individuals with HDGC undergo prophylactic total gastrectomy (PTG) to eliminate this risk. However, PTG is associated with significant lifestyle changes, post-surgical recovery, and symptom burden. This study examined factors related to decision-making about PTG in three groups of individuals who: (1) underwent PTG immediately after receiving genetic testing results; (2) delayed PTG by ≥ 1 year or; (3) declined PTG. Participants were recruited from a familial gastric cancer registry at a tertiary care hospital. Patients with CDH1 pathogenic or likely pathogenic variants who contemplated and/or underwent PTG were eligible. 24 individuals contemplated PTG: 9 had immediate surgery (within a year), 8 delayed surgery, and 7 declined surgery. Data on PTG barriers and facilitators were obtained on all participants using quantitative surveys (n = 7), qualitative interviews (n = 8) or both methods (n = 9). PTG barriers included age, positive beliefs about screening, close relatives with negative PTG experiences, fertility-related concerns, and life stress. Facilitators included social support, trust in healthcare providers, understanding risk, negative beliefs about screening, family-related factors, positive or abnormal screening results, and positive attitude toward PTG. This study highlights factors related to the PTG decision-making process among individuals with HDGC from three distinct groups. Future research should explore educational interventions aimed at addressing surgery-related concerns and the limitations of screening, and might also consider incorporating close relatives as informational supports.

Hereditary Gastric and Breast Cancer Syndromes Related to CDH1 Germline Mutation: A Multidisciplinary Clinical Review

E-cadherin (CDH1 gene) germline mutations are associated with the development of diffuse gastric cancer in the context of the so-called hereditary diffuse gastric syndrome, and with an inherited predisposition of lobular breast carcinoma. In 2019, the international gastric cancer linkage consortium revised the clinical criteria and established guidelines for the genetic screening of CDH1 germline syndromes. Nevertheless, the introduction of multigene panel testing in clinical practice has led to an increased identification of E-cadherin mutations in individuals without a positive family history of gastric or breast cancers. This observation motivated us to review and present a novel multidisciplinary clinical approach (nutritional, surgical, and image screening) for single subjects who present germline CDH1 mutations but do not fulfil the classic clinical criteria, namely those identified as-(1) incidental finding and (2) individuals with lobular breast cancer without family history of gastric cancer (GC).

Prophylactic Surgery and Extended Oncologic Radicality in Gastric and Colorectal Hereditary Cancer Syndromes

Prophylactic surgery for high-penetrance hereditary gastric and colorectal cancer can be a primary prophylaxis of cancer and a secondary oncologic prevention. As early cancer is often detected in the resected organ, there has been no prophylaxis of cancer but cancer treatment. Extended oncological radicality with removal of the complete organ is a tertiary prevention as metachronous cancer is avoided. The indication for prophylactic surgery or extended oncological radicality is presented regarding hereditary and familial gastric and colorectal cancer. Hereditary diffuse type gastric cancer (E-cadherin mutation) and familial adenomatous polyposis coli (APC or MYH mutation) are well-accepted indications for prophylactic surgery with a variety of considerations regarding phenotype, genotype, associated diseases, age, timing, extent, and technique of surgery. Not so much prophylactic surgery as extended oncologic radicality can be considered in familial gastric and colorectal cancer as well as Lynch or hereditary nonpolyposis colorectal cancer syndrome (HNPCC). Clinical, molecular, and technical progress leads to less invasive and risk-adapted surgical and nonsurgical interventions, expanding the variety of individualized treatment options.