Small bowel adenocarcinoma phenotyping, a clinicobiological prognostic study

Enhancing treatment strategies for small bowel cancer: a clinical review of targeted therapy and immunotherapy approaches

Small bowel cancer (SBC) is a rare and aggressive disease with a poor prognosis, necessitating the exploration of novel treatment approaches. This narrative review examines the current evidence on targeted therapy and immunotherapy for SBC, focusing on the two most common subtypes: adenocarcinoma and neuroendocrine tumor. A comprehensive search of PubMed, Scopus, and Google Scholar databases was conducted to identify relevant clinical trials and case reports published in English up to September 2023. The review includes 17 clinical trials and 10 case reports, indicating that targeted therapy and immunotherapy can have the potential to improve survival rates in patients with SBC. Notably, promising targeted medicines include bevacizumab, cetuximab, and trastuzumab, while pembrolizumab and nivolumab show potential as immunotherapies. However, it should be noted that the magnitude of the increase in survival rates with these interventions was small. Further research is needed to determine the optimal combination of targeted therapy and immunotherapy for individual patients with SBC.

Genomic profiling of small bowel adenocarcinoma: a pooled analysis from 3 databases

BACKGROUND

Small bowel adenocarcinoma is a rare disease. The genomic profiling tumours according to clinical characteristics and its impact on the prognosis remains unclear.

METHODS

A pooled analysis of clinical data, genomic profiling and MisMatch Repair (MMR) status from three databases was performed.

RESULTS

A total of 188 tumour samples were analysed. A predisposing disease was reported in 22.3%, mainly Lynch syndrome and Crohn's disease. The tumours were localized in 80.2% and metastatic in 18.8%. The most frequent mutations were KRAS (42.0%) among them 7/79 are G12C, TP53 (40.4%), APC (19.1%), PIK3CA (18.6%), SMAD4 (12.8%) and ERBB2 (9.6%). Mutation distribution differed according to predisposing disease for TP53, ERBB2, IDH1, FGFR3, FGFR1 and KDR. KRAS and SMAD4 mutations were more frequent in metastatic tumour, whereas ERBB2 mutations were absent in metastatic tumour. For localized tumour, APC mutation was independently associated with a poor overall survival (OS) (p = 0.0254). 31.8% of localized tumours and 11.3% of metastatic tumours were dMMR (29.8% of the entire cohort). A dMMR status was associated with a better OS (HR = 0.61 [0.39-0.96], p = 0.0316).

CONCLUSIONS

There is a different genomic profile according to the stage and predisposing disease. dMMR and APC mutation in localized tumour predict a better prognosis.

A multicenter study evaluating efficacy of immune checkpoint inhibitors in advanced non-colorectal digestive cancers with microsatellite instability

BACKGROUND

One randomized phase III trial comparing chemotherapy (CT) with immune checkpoint inhibitors (ICI) has demonstrated significant efficacy of ICI in deficient DNA mismatch repair system/microsatellite instability-high (dMMR/MSI-H) metastatic colorectal cancer. However, few studies have compared ICI with CT in other advanced dMMR/MSI-H digestive tumors.

METHODS

In this multicenter study, we included patients with advanced dMMR/MSI-H non-colorectal digestive tumors treated with chemotherapy and/or ICIs. Patients were divided retrospectively into two groups, a CT group and an immunotherapy (IO) group. The primary endpoint was progression-free survival (PFS). A propensity score approach using the inverse probability of treatment weighting (IPTW) method was applied to deal with potential differences between the two groups.

RESULTS

133 patients (45.1/27.1/27.8% with gastric/small bowel/other carcinomas) were included. The majority of patients received ICI in 1st (29.1%) or 2nd line (44.4%). The 24-month PFS rates were 7.9% in the CT group and 71.2% in the IO group. Using the IPTW method, IO treatment was associated with better PFS (HR=0.227; 95% CI 0.147-0.351; p < 0.0001). The overall response rate was 26.3% in the CT group versus 60.7% in the IO group (p < 0.001) with prolonged duration of disease control in the IO group (p < 0.001). In multivariable analysis, predictive factors of PFS for patients treated with IO were good performance status, absence of liver metastasis and prior primary tumor resection, whereas no association was found for the site of the primary tumor.

CONCLUSIONS

In the absence of randomized trials, our study highlights the superior efficacy of ICI compared with standard-of-care therapy in patients with unresectable or metastatic dMMR/MSI-H non-colorectal digestive cancer, regardless of tumor type, with acceptable toxicity.

Molecular characterization of Chinese patients with small bowel adenocarcinoma

PURPOSE

Small bowel adenocarcinoma (SBA) is a rare malignancy of the gastrointestinal tract, and its unique location within the small intestine presents difficulties in obtaining tissue samples from the lesions. This limitation hinders the research and development of effective clinical treatment methods. Circulating tumor DNA (ctDNA) analysis holds promise as an alternative approach for investigating SBA and guiding treatment decisions, thereby improving the prognosis of SBA.

METHODS

Between January 2017 and August 2021, a total of 336 tissue or plasma samples were obtained and the corresponding mutation status in tissue or blood was evaluated with NGS.

RESULTS AND CONCLUSIONS

The study found that in SBA tissues, the most commonly alternated genes were TP53, KRAS, and APC, and the most frequently affected pathways were RTK-RAS-MAPK, TP53, and WNT. Notably, the RTK-RAS-MAPK pathway was identified as a potential biomarker that could be targeted for treatment. Then, we validated the gene mutation profiling of ctDNA extracted from SBA patients exhibited the same characteristics as tissue samples for the first time. Subsequently, we applied ctDNA analysis on a terminal-stage patient who had shown no response to previous chemotherapy. After detecting alterations in the RTK-RAS-MAPK pathway in the ctDNA, the patient was treated with MEK + EGFR inhibitors and achieved a tumor shrinkage rate of 76.33%. Our study utilized the largest Chinese SBA cohort to uncover the molecular characteristics of this disease, which might facilitate clinical decision making for SBA patients.

Incidence, clinical management and prognosis of patients with small intestinal adenocarcinomas from 1999 through 2019: A nationwide Dutch cohort study

BACKGROUND

Small intestinal adenocarcinomas (SIAs) are rare. Hence, randomized controlled trials are lacking and understanding of the disease features is limited. This nationwide cohort investigates incidence, treatment and prognosis of SIA patients, to improve disease outcome.

PATIENTS AND METHODS

Data of 2697 SIA patients diagnosed from January 1999 through December 2019 were retrieved from the Netherlands Cancer Registry and Pathology Archive. Incidence was calculated using the revised European Standardized Rate. The influence of patient and tumor characteristics on overall survival (OS) was studied using survival analyses.

RESULTS

The age-standardized incidence rate almost doubled from 0.58 to 1.06 per 100,000 person-years, exclusively caused by an increase in duodenal adenocarcinomas. OS did not improve over time. Independent factors for a better OS were a younger age, jejunal tumors, Lynch syndrome and systemic therapy. Only 13.8% of resected patients was treated with adjuvant chemotherapy, which improved OS compared to surgery alone in stage III disease (HR 0.47 (0.35-0.61)), but not in the limited group of deficient mismatch repair (MMR) patients (n = 53, HR 0.93 (0.25-3.47)). In the first-line setting, CAPOX was associated with improved OS compared to FOLFOX (HR 0.51 (0.36-0.72)). For oligometastatic patients, a metastasectomy significantly improved OS (HR 0.54 (0.36-0.80)).

CONCLUSIONS

The incidence of SIAs almost doubled in the past 20 years, with no improvement in OS. This retrospective non-randomized study suggests the use of adjuvant chemotherapy for stage III disease and first-line CAPOX for metastatic patients. For selected oligometastatic patients, a metastasectomy may be considered. MMR-status testing could aid in clinical decision-making.

Adjuvant chemotherapy benefit according to T and N stage in small bowel adenocarcinoma: a large retrospective multicenter study

BACKGROUND

Small bowel adenocarcinoma is a rare cancer, and the role of adjuvant chemotherapy for localized disease is still debated.

METHODS

This retrospective multicenter study included all consecutive patients who underwent curative surgical resection for localized small bowel adenocarcinoma between 1996 and 2019 from 3 French cohort studies. Prognostic and predictive factors of adjuvant chemotherapy efficacy were analyzed for disease-free survival and overall survival. The inverse probability of treatment weighting method was applied in the Cox regression model using the propensity score derived from multivariable logistic regression.

RESULTS

A total of 354 patients were included: median age, 63.5 years; duodenum location, 53.5%; and tumor stage I, II, and III in 31 (8.7%), 144 (40.7%), and 179 (50.6%) patients, respectively. The adjuvant chemotherapy was administered in 0 (0%), 66 (48.5%), and 143 (80.3%) patients with stage I, II, and III, respectively (P < .0001). In the subgroup analysis by inverse probability of treatment weighting method, a statistically significant disease-free survival and overall survival benefit in favor of adjuvant chemotherapy was observed in high-risk stage II (T4 and/or <8 lymph nodes examined) and III (T4 and/or N2) but not for low-risk stage II (T3 and ≥8 lymph nodes examined) and III (T1-3/N1) tumors (Pinteraction < .05). Furthermore, tumor location in jejunum and ileum was also a statistically significant predictive factor of response to adjuvant chemotherapy in stage II and III tumors (Pinteraction < .05).

CONCLUSION

In localized small bowel adenocarcinoma, adjuvant chemotherapy seems to provide a statistically significant survival benefit for high-risk stage II and III tumors and for jejunum and ileum tumor locations.

Microsatellite instability in the high-grade dysplasia component of duodenal adenoma is associated with progression to adenocarcinoma

PURPOSE

We examined the microsatellite instability of duodenal tumors to evaluate their molecular features associated with the adenoma-carcinoma sequence.

METHODS

Fifty-two non-ampullary duodenal epithelial tumors collected by endoscopic mucosal resection or surgical resection were studied. When a tumor had two or more dysplasia grades, the highest grade was considered. Representative areas were macro-dissected and subjected to a microsatellite instability analysis and immunohistochemical staining.

RESULTS

The 52 tumors were classified as either adenoma with low-grade dysplasia (n = 18), adenoma with high-grade dysplasia (n = 20), or adenocarcinomas (n = 14). Among these, 3 adenocarcinoma cases showed microsatellite instability and the remaining 49 tumors showed microsatellite stability. Of the 14 adenocarcinoma cases, 3 contained both high-grade dysplasia and adenocarcinoma components, and 11 contained only the adenocarcinoma component. Interestingly, all three adenocarcinoma + high-grade dysplasia cases were microsatellite instability-high in both the adenocarcinoma and high-grade dysplasia components. Immunohistochemical staining of mismatch repair proteins showed mismatch repair deficiency in three microsatellite instability-high adenocarcinoma + high-grade dysplasia cases.

CONCLUSIONS

Only adenocarcinoma cases with high-grade dysplasia components were microsatellite instability-high (in both the adenocarcinoma and high-grade dysplasia components). This suggests that microsatellite instability in the high-grade dysplasia component of duodenal adenoma is associated with progression to adenocarcinoma.

Evaluation of Systemic Treatments of Small Intestinal Adenocarcinomas: A Systematic Review and Meta-analysis

IMPORTANCE

Although small intestinal adenocarcinomas (SIAs) are rare, they have a poor prognosis, and the optimal treatment strategies are largely unknown. Because of the lack of high-quality evidence, guidelines for colorectal cancer are often followed in the treatment of SIAs.

OBJECTIVE

To review the current evidence regarding survival benefit of systemic therapies, including chemotherapy, targeted agents, and immunotherapy, for patients with SIAs.

DATA SOURCES

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses, MEDLINE and Embase were searched for articles published from January 1, 2005, until June 1, 2022.

STUDY SELECTION

Retrospective cohort studies and prospective phase 2 or 3 trials describing survival after systemic therapies for patients with SIAs were eligible for inclusion. Assessment of study eligibility was blinded and performed by 3 reviewers.

DATA EXTRACTION AND SYNTHESIS

The reviewers independently extracted data. Random effects, inverse variance, pairwise meta-analyses were performed.

MAIN OUTCOMES AND MEASURES

Primary outcomes were overall survival (OS) and progression-free survival (PFS) of patients with SIAs after systemic therapies. Measures of interest included hazard ratios for survival and median survival times.

RESULTS

Overall, 57 retrospective cohort and phase 2 studies of 35 176 patients were included. Adjuvant chemotherapy, generally fluoropyrimidine-based, was associated with increased OS in stage I to III SIAs (hazard ratio [HR], 0.60; 95% CI, 0.53-0.68), especially in stage III tumors (HR, 0.55; 95% CI, 0.48-0.64), irrespective of tumor localization. Palliative chemotherapy was also associated with an OS benefit (HR, 0.48; 95% CI, 0.40-0.58). Fluoropyrimidine-oxaliplatin combinations were superior to other regimens (OS: HR, 0.54; 95% CI, 0.30-0.99; PFS: HR, 0.46; 95% CI, 0.30-0.71). Furthermore, bevacizumab added to chemotherapy compared with chemotherapy alone was associated with significantly prolonged PFS (HR, 0.62; 95% CI, 0.43-0.89). Immunotherapy showed a 50% overall response rate in previously treated defective mismatch repair tumors.

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, adjuvant and palliative chemotherapy were both associated with improved survival of patients with SIAs, especially fluoropyrimidine-based regimens and fluoropyrimidine-oxaliplatin combinations. Adding bevacizumab to chemotherapy appears to prolong PFS and deserves further investigation. Immunotherapy seems beneficial and should be considered for patients with defective mismatch repair tumors. International collaborations should be undertaken to confirm and improve efficacy of systemic therapies for patients with SIAs.

The Role of Tumor-Associated Antigen HER2/neu in Tumor Development and the Different Approaches for Using It in Treatment: Many Choices and Future Directions

The treatment of HER2-positive cancers has changed significantly over the past ten years thanks to a significant number of promising new approaches that have been added to our arsenal in the fight against cancer, including monoclonal antibodies, inhibitors of tyrosine kinase, antibody-drug conjugates, vaccination, and particularly, adoptive-T-cell therapy after its great success in hematological malignancies. Equally important is the new methodology for determining patients eligible for targeted HER2 therapy, which has doubled the number of patients who can benefit from these treatments. However, despite the initial enthusiasm, there are still several problems in this field represented by drug resistance and tumor recurrence that require the further development of new more efficient drugs. In this review, we discuss various approaches for targeting the HER2 molecule in cancer treatment, highlighting their benefits and drawbacks, along with the different mechanisms responsible for resistance to HER2-targeted therapies and how to overcome them.

Clinical practice guidelines for duodenal cancer 2021

Duodenal cancer is considered to be a small intestinal carcinoma in terms of clinicopathology. In Japan, there are no established treatment guidelines based on sufficient scientific evidence; therefore, in daily clinical practice, treatment is based on the experience of individual physicians. However, with advances in diagnostic modalities, it is anticipated that opportunities for its detection will increase in future. We developed guidelines for duodenal cancer because this disease is considered to have a high medical need from both healthcare providers and patients for appropriate management. These guidelines were developed for use in actual clinical practice for patients suspected of having non-ampullary duodenal epithelial malignancy and for patients diagnosed with non-ampullary duodenal epithelial malignancy. In this study, a practice algorithm was developed in accordance with the Minds Practice Guideline Development Manual 2017, and Clinical Questions were set for each area of epidemiology and diagnosis, endoscopic treatment, surgical treatment, and chemotherapy. A draft recommendation was developed through a literature search and systematic review, followed by a vote on the recommendations. We made decisions based on actual clinical practice such that the level of evidence would not be the sole determinant of the recommendation. This guideline is the most standard guideline as of the time of preparation. It is important to decide how to handle each case in consultation with patients and their family, the treating physician, and other medical personnel, considering the actual situation at the facility (and the characteristics of the patient).

Concurrent loss of MLH1, PMS2 and MSH6 immunoexpression in digestive system cancers indicating a widespread dysregulation in DNA repair processes

Immunohistochemical analysis of mismatch repair (MMR) protein expression is widely used to identify tumors with a deficient MMR (dMMR). MMR proteins (MLH1/PMS2 and MSH2/MSH6) work as functional heterodimers, which usually leads to the loss of expression in only one functional MMR heterodimer. Recently, there have been studies showing the simultaneous loss of immunoexpression in proteins of both heterodimers. Yet, this phenomenon has been rarely investigated. In this study, we retrospectively considered cases of different digestive system cancers (gastric cancer, ampullary cancer, small bowel cancer, colorectal cancer), which were immunohistochemically tested for dMMR within a 4-year period at our university hospital (n=352). Of the 103 cases showing dMMR, 5 cases (1.4% of all, 5.1% of dMMR cases) showed a concurrent loss of MLH1, PMS2 and MSH6 immunoexpression, whereas in the other 98 dMMR cases only one MMR heterodimer was affected. MLH1^-/PMS2^-/MSH6^- cancer cases almost arose throughout the entire digestive tract: from the gastric antrum to the left colic flexur. To provide a comprehensive molecular characterization of this MLH1^-/PMS2^-/MSH6^- immunophenotype, tumors were analyzed for microsatellite instability, MLH1 promotor hypermethylation and BRAF exon 15 status. Furthermore, we performed next-generation sequencing focusing on genes related to DNA repair. Here, we could detect pathogenic germline variants as well as multiple sporadic mutations in different genes involved in MMR and homologous recombination repair (HRR) respectively. The affected MMR/HRR-related genes were: ATM, BARD1, BRCA1, CDK12, CHEK1, CHEK2, FANCA, MLH1, MSH6, PALB2, TP53. Considering the biologic function of HRR/MMR proteins as potential drug targets and the low frequency of most of these mutations in digestive system cancers in general, their common occurrence in our MLH1^-/PMS2^-/MSH6^- cases seems to be even more noteworthy, highlighting the need for recognition, awareness and further investigation of this unusual IHC staining pattern.

Genetic analysis of Japanese patients with small bowel adenocarcinoma using next-generation sequencing

BACKGROUND

Small bowel adenocarcinomas (SBAs) are rare and there is little comprehensive data on SBA genomic alterations for Asian patients. This study aimed to profile genomic alterations of SBA in Japanese patients using targeted next-generation sequencing (NGS).

METHODS

We examined 22 surgical resections from patients with primary SBA. SBA genomic alterations were analyzed by NGS. Mismatch repair (MMR) status was determined by immunohistochemical analysis. Mucin phenotypes were classified as gastric (G), intestinal (I), gastrointestinal (GI), and null (N) types on MUC2, MUC5AC, MUC6, and CD10 immunostaining.

RESULTS

The most common genomic alterations found in SBA tumors were TP53 (n = 16), followed by KRAS (n = 6), APC (n = 5), PIK3CA (n = 4), CTNNB1 (n = 3), KIT (n = 2), BRAF (n = 2), CDKN2A (n = 2), and PTEN (n = 2). Deficient MMR tumors were observed in 6 out of 22 patients. Tumor mucin phenotypes included 2 in G-type, 12 in I-type, 3 in GI-type, and 5 in N-type. APC and CTNNB1 mutations were not found in G-type and GI-type tumors. KRAS mutations were found in all tumor types except for G-type tumors. TP53 mutations were found in all tumor types. Although no single gene mutation was associated with overall survival (OS), we found that KRAS mutations were associated with significant worse OS in patients with proficient MMR tumors.

CONCLUSIONS

SBA genomic alterations in Japanese patients do not differ significantly from those reports in Western countries. Tumor localization, mucin phenotype, and MMR status all appear to impact SBA gene mutations.

Localized Small Bowel Adenocarcinoma Management: Evidence Summary

Small bowel cancers are rare diseases whose prognosis is poorer than that of colon cancers. Due to disease rarity, there is little data on small bowel adenocarcinoma (SBA) treatment, and most recommendations come from expert agreements or analogies to the management of colon cancer. Although relatively high rates of local recurrence are observed for duodenal malignancies, distant metastatic relapse remains common and requires adjuvant systemic therapy. Given the similarities between SBA and colorectal cancer, radiotherapy and chemotherapy strategies used for the latter disease are frequently pursued for the former disease, specifically for tumors located in the duodenum. However, no previous randomized study has evaluated the benefit of adjuvant chemotherapy on the overall survival of SBA patients. Most previous studies on treatment outcomes and prognostic factors in this context were based on large international databases, such as the Surveillance, Epidemiology, and End Results or the National Cancer Database. Studies are required to establish and validate prognostic and predictive markers relevant in this context to inform the use of (neo) adjuvant treatment. Among those, deficient mismatch repair tumors represent 20% of SBAs, but their impact on chemosensitivity remains unknown. Herein, we summarize the current evidence on the management of localized SBA, including future perspectives.

Epidemiology, Risk Factors and Diagnosis of Small Bowel Adenocarcinoma

Simple Summary

Small bowel adenocarcinoma is a rare tumor. Diagnosis is often obtained at an advanced stage and prognosis remains poor. The aim of this review is to report the recent epidemiological and risk factor data related to small bowel adenocarcinoma. New diagnostic tools are also described in this review.

Abstract

Adenocarcinomas of the small intestine are rare tumors but their incidence is increasing. There is a slight male predominance. The median age at diagnosis is the 6th decade. The most frequent primary location is the duodenum. There is no clearly identified environmental risk factor, but adenocarcinomas of the small intestine are associated in almost 20% of cases with predisposing diseases (Crohn’s disease, Lynch syndrome, familial adenomatous polyposis, Peutz–Jeghers syndrome and celiac disease).

Molecular Landscape of Small Bowel Adenocarcinoma

Small bowel adenocarcinoma (SBA) is a rare malignancy, with lower incidence, later stage at diagnosis, and poor overall prognosis compared to other cancers of the gastrointestinal tract. Owing to the rarity of the disease along with the paucity of high-quality tissue samples and preclinical models, little is known about the molecular alterations characteristic of SBA. This is reflected by the fact that the clinical management of SBA is primarily extrapolated from colorectal cancer (CRC). Recent advances in genomic profiling have highlighted key differences between these tumors, establishing SBA as a molecularly unique intestinal cancer. Moreover, comprehensive molecular analysis has identified a relatively high incidence of potentially targetable genomic alterations in SBA, predictive of response to targeted and immunotherapies. Further advances in our knowledge of the mutational and transcriptomic landscape of SBA, guided by an increased understanding of the molecular drivers of SBA, will provide opportunities to develop novel diagnostic tools and personalized therapeutic strategies.

Small bowel adenocarcinoma: An overview

Small bowel adenocarcinoma (SBA) is a rare malignancy of the gastrointestinal tract. However, these tumors are among those with worst prognosis. Vague clinical signs and symptoms and radiological diagnostic challenges often delay treatment, which negatively impacts the prognosis of the patients. However, recent advances in imaging technology, like multidetector computed tomography, magnetic resonance imaging, and capsule endoscopy, have made earlier and accurate diagnosis possible. Surgery is the treatment of choice followed by adjuvant therapy. However, there are no strict treatment guidelines available for the management of SBA. Most of the available evidence from colorectal and gastric carcinoma has been extrapolated to adequately manage SBA. Prognosis for SBA is better than gastric carcinoma but worse than colorectal carcinoma. Currently, there is not enough information on the molecular characteristics and tumor pathogenesis. Because the incidence of SBA is very low, there is a need for further studies to evaluate the possible application of newer investigative agents and strategies to obtain a better outcome within the framework of international collaborations.

TMC5 is Highly Expressed in Human Cancers and Corelates to Prognosis and Immune Cell Infiltration: A Comprehensive Bioinformatics Analysis

Background: The oncological role of TMC5 in human cancers has only been revealed partially. We performed integrated bioinformatics analysis to provide a thorough and detailed insight of associations between TMC5 and tumorigenesis, cancer progression, and prognosis.

Methods: With reference to the accessible online databases, the TMC5 expressions in tumor tissues and corresponding normal tissues, different pathological stages, and various cancer cells were analyzed, while the protein levels of TMC5 in different cancers were also inspected. Meanwhile, the prognostic value of TMC5 expression in multiple cancers as well as in advanced-stage patients was investigated. Furthermore, the mutational data of TMC5 and its correlation with cancer prognosis were assessed. Moreover, the association between the TMC5 level and immune cell infiltration was evaluated. Next, TMC5-related pathway alterations and drug responses were summarized. Finally, the TMC5 based protein network was generated, and relevant enrichment was performed.

Results: In our study, the expression level of TMC5 was significantly higher in the tumor tissue than that of the normal tissues in most cancer types. Fluctuations of TMC5 levels were also observed among different pathological stages. In the meantime, the protein level elevated in the tumor tissue in the cancers enrolled. Moreover, the expression of TMC5 was not only prognostic for overall survival (OS) or recurrence free survival (RFS) in various types of cancers but also correlated to OS in patients with more advanced cancers. Additionally, the mutational status of TMC5 is also associated with prognosis in cancer patients. It is worth noting that the TMC5 level was closely related to immune cell infiltrations, especially in ESCA, TGCT, and USC. The TMC5 expression was also identified as an activator for pathways including PI3K/AKT, RAS/MAPK, and TSC/mTOR, proved to be associated with multiple drug responses and assessed to be interactive with the TMEM family.

Conclusion: TMC5 might function as a potential marker for cancer survival and immune responses.

Identification of Lynch Syndrome Carriers among Patients with Small Bowel Adenocarcinoma

Simple Summary

Small bowel adenocarcinoma (SBA) is associated with Lynch syndrome (LS). This is the first study to evaluate the identification of LS patients based on mismatch repair deficiency (MMRd) tumor among SBA. The authors found a 21.3% prevalence of MMRd tumors and a 10.1% prevalence of LS. A germline mutation was identified in 60% of patients with a MMRd tumor. This data suggests that universal tumor MMR testing among SBA patients should be implemented for the identification of LS.

Abstract

Background: Small bowel adenocarcinoma (SBA) is a rare disease which can be associated with Lynch syndrome (LS). LS tumors are characterized by the presence of microsatellite instability (MSI) and/or the loss of mismatch repair (MMR) protein expression. In SBA, the frequency of MMR deficient (MMRd) tumors varies from 5% to 35%. This study aims to describe the prevalence of LS carriers among patients with MMRd small bowel adenocarcinomas. Methods: A multicenter retrospective study with identification and MMR testing of all consecutive SBA between 2004 and 2020 in a multicenter Spanish study. Demographical data, tumor characteristics, follow-up and survival information were collected. Germline testing was driven by identification of MMRd tumors. Results: A total of 94 individuals diagnosed with SBA were recruited. We observed 20 (21.3%) MMRd tumors. In 9/15 (60%) patients with MMRd tumors, a pathogenic variant was identified (three MLH1, four MSH2, one MSH6 and one PMS2). Accordingly, the prevalence of LS among all SBA cases was 10.1%. Conclusions: More than one-fifth of SBA display MMRd and in more than a half is due to LS. Our data supports the implementation of universal MMR tumor testing among SBA for the identification of LS families.

APC mutations are common in adenomas but infrequent in adenocarcinomas of the non-ampullary duodenum

BACKGROUND

Recent studies highlighted the clinicopathological heterogeneity of non-ampullary duodenal adenomas and adenocarcinomas, but the detailed process of the malignant transformation remains unclear.

METHODS

We analyzed 144 adenomas and 54 adenocarcinomas of the non-ampullary duodenum for immunohistochemical phenotypes, genetic alterations, and mismatch repair (MMR) status to probe their histogenetic relationship.

RESULTS

The median ages of patients with adenoma and adenocarcinoma were the same (66 years). Adenomas were histologically classified as intestinal-type adenoma (n = 124), pyloric gland adenoma (PGA, n = 10), gastric-type adenoma, not otherwise specified (n = 9), and foveolar-type adenoma (n = 1). Protein-truncating APC mutations were highly frequent in adenomas (85%), with the highest prevalence in intestinal-type adenomas (89%), but rare in adenocarcinomas (9%; P = 2.1 × 10^-23). Close associations between phenotypic marker expression and genetic alterations were observed in adenomas, but not in adenocarcinomas, excluding the common association between GNAS mutations and MUC5AC expression. MMR deficiency was more frequent in adenocarcinomas (20%) than in adenomas (1%; P = 2.6 × 10^-6). One MMR-deficient adenoma and three MMR-deficient adenocarcinomas occurred in patients with Lynch syndrome. Additionally, three other patients with an MMR-deficient adenocarcinoma fulfilled the revised Bethesda criteria.

CONCLUSION

The discrepant APC mutation frequency between adenomas and adenocarcinomas suggests that APC-mutated adenomas, which constitute the large majority of non-ampullary duodenal adenomas, are less prone to malignant transformation. Non-ampullary duodenal adenocarcinomas frequently exhibit MMR deficiency and should be subject to MMR testing to determine appropriate clinical management, including the identification of patients with Lynch syndrome.

Immunohistochemistry as predictive and prognostic markers for gastrointestinal malignancies

Biomarkers play a key role in the comprehensive pathologic evaluation of gastrointestinal malignancies. These biomarkers can be predictive, indicating whether a tumor is likely to respond to a particular therapy, or prognostic, providing information about the likely course and outcome of a disease. This review article will discuss available immunohistochemical stains for assessing these markers, including staining rationale, scoring criteria, associated systemic therapies, and pictorial examples. PD-L1, HER2, and mismatch repair status can be evaluated via immunohistochemistry for esophageal, gastric, and colorectal carcinomas. Biomarkers currently play a more limited role in evaluation of pancreatic and small bowel malignancies. Immunohistochemistry can also be used to evaluate biomarker status in gastrointestinal stromal tumors, gastrointestinal malignancies with NTRK gene fusions, and undifferentiated carcinomas with switch-sucrose non-fermentable complex abnormalities.

The Risk of Malignancies in Celiac Disease-A Literature Review

Celiac disease (CeD) is an immune-mediated enteropathy precipitated by ingestion of gluten in genetically predisposed individuals. Considering that CeD affects approximately 1% of the Western population, it may be considered a global health problem. In the large majority of cases, CeD has a benign course, characterized by the complete resolution of symptoms and a normal life expectancy after the beginning of a gluten-free-diet (GFD); however, an increased risk of developing malignancies, such as lymphomas and small bowel carcinoma (SBC), has been reported. In particular, enteropathy-associated T-cell lymphoma (EATL), a peculiar type of T-cell lymphoma, is characteristically associated with CeD. Moreover, the possible association between CeD and several other malignancies has been also investigated in a considerable number of studies. In this paper, we aim to provide a comprehensive review of the current knowledge about the associations between CeD and cancer, focusing in particular on EATL and SBC, two rare but aggressive malignancies.

Vascular endothelial growth factor-A is an Immunohistochemical biomarker for the efficacy of bevacizumab-containing chemotherapy for duodenal and jejunal adenocarcinoma

BACKGROUND

The efficacy and safety of bevacizumab-containing chemotherapy for patients with metastatic duodenal and jejunal adenocarcinoma (mDJA) are unclear. The present study aimed to evaluate the efficacy of bevacizumab and to explore immunohistochemical markers that can predict the efficacy of bevacizumab for patients with mDJA.

METHODS

This multicentre study included patients with histologically confirmed small bowel adenocarcinoma who received palliative chemotherapy from 2008 to 2017 at 15 hospitals. Immunostaining was performed for vascular endothelial growth factor-A (VEGF-A), TP53, Ki67, β-catenin, CD10, MUC2, MUC5AC, MUC6, and mismatch repair proteins.

RESULTS

A total of 74 patients were enrolled, including 65 patients with mDJA and 9 with metastatic ileal adenocarcinoma. Patients with mDJA who received platinum-based chemotherapy with bevacizumab as first-line treatment tended to have a longer progression-free survival and overall survival than those treated without bevacizumab (P = 0.075 and 0.077, respectively). Multivariate analysis extracted high VEGF-A expression as a factor prolonging progression-free survival (hazard ratio: 0.52, 95% confidence interval: 0.30-0.91). In mDJA patients with high VEGF-A expression, those who received platinum-based chemotherapy with bevacizumab as a first-line treatment had significantly longer progression-free survival and tended to have longer overall survival than those treated without bevacizumab (P = 0.025 and P = 0.056, respectively), whereas no differences were observed in mDJA patients with low VEGF-A expression.

CONCLUSION

Immunohistochemical expression of VEGF-A is a potentially useful biomarker for predicting the efficacy of bevacizumab-containing chemotherapy for patients with mDJA.

Molecular profiling and identification of prognostic factors in Chinese patients with small bowel adenocarcinoma

Small bowel adenocarcinoma (SBA) is a rare malignancy with a poor prognosis and limited treatment options. Despite prior studies, molecular characterization of this disease is not well defined, and little is known regarding Chinese SBA patients. In this study, we conducted multigene next-generation sequencing and 16S ribosomal RNA gene sequencing on samples from 76 Chinese patients with surgically resected primary SBA. Compared with colorectal cancer and Western SBA cohorts, a distinctive genomic profile was revealed in Chinese SBA cohorts. According to the levels of clinical actionability to targetable alterations stratified by OncoKB system, 75% of patients harbored targetable alterations, of which ERBB2, BRCA1/2, and C-KIT mutations were the most common targets of highest-level actionable alterations. In DNA mismatch repair-proficient (pMMR) patients, significant associations between high tumor mutational burden and specific genetic alterations were identified. Moreover, KRAS mutations/TP53 wild-type/nondisruptive mutations (KRAS^mut /TP53^wt/non-dis ) were independently associated with an inferior recurrence-free survival (hazard ratio [HR] = 4.21, 95% confidence interval [CI] = 1.94-9.14, P < .001). The bacterial profile revealed Proteobacteia, Actinobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Cyanobacteria were the most common phyla in SBA. Furthermore, patients were clustered into three subgroups based on the relative abundance of bacterial phyla, and the distributions of the subgroups were significantly associated with the risk of recurrence stratified by TP53 and KRAS mutations. In conclusion, these findings provided a comprehensive molecular basis for understanding SBA, which will be of great significance in improving the treatment strategies and clinical management of this population.

The incidence of non-ampullary duodenal cancer in Japan: The first analysis of a national cancer registry

BACKGROUND AND AIM

Although duodenal cancer is rare, no epidemiological research on this disease has been conducted in Asian countries. We aimed to elucidate the incidence and clinical features of duodenal cancer in Japan using a large-scale national database.

METHODS

Data of patients with primary duodenal cancer diagnosed from January 1, 2016, to December 31, 2016, were extracted from the Japanese national cancer registry. Excluding malignant neoplasm of the Vater's ampulla, we calculated the incidence among the population as a crude number of patients with duodenal cancer divided by the total Japanese population in 2016. We performed multivariate analyses using logistic regression models to identify risk factors for advanced cancer, defined as metastatic cancer or local invasion to adjacent organs.

RESULTS

Data on 3005 patients were included. The incidence of duodenal cancer was 23.7 per 1 000 000 person-years. In total, 56.4% of cases were detected at the localized stage. In the localized cancer group, endoscopic resection was more frequently performed (48.0%), whereas in the advanced cancer group, surgery and chemotherapy were the major treatment options (39.3% and 41.5%, respectively). Multivariate analyses identified age ≥80 years (odds ratio [OR], 1.489; 95% confidence interval [CI], 1.113-1.992; P = 0.007), incidental detection (OR, 2.325; CI, 1.623-3.331; P < 0.0001), and precise examination for symptomatic patients (OR, 10.561; CI, 7.416-15.042; P < 0.0001) as independent risk factors for advanced cancer.

CONCLUSIONS

Our study revealed the incidence of duodenal cancer in Japan. However, localized cancer was the major tumor stage at detection, resulting in a high rate of endoscopic resection.

Case Report: Molecular Features and Treatment Options for Small Bowel Adenocarcinoma

Small bowel adenocarcinoma (SBA) is a rare malignancy characterized by poor prognosis. Recent efforts have sought to elucidate the genetic landscape and the molecular drivers behind this disease. Herein, we report the main molecular alterations in two metastatic (stage IV) SBA patients. Interestingly, one of them had gene alterations that affected signaling pathways previously described for SBA. However, a second patient displayed previously unreported alterations in this particular tumor type. Based on these findings we discuss potential treatment options for patients affected by this rare, aggressive disease.

Diagnosis of Lynch Syndrome and Strategies to Distinguish Lynch-Related Tumors from Sporadic MSI/dMMR Tumors

Simple Summary

Microsatellite instability (MSI) is a hallmark of Lynch syndrome (LS)-related tumors but is not specific, as most of MSI/mismatch repair-deficient (dMMR) tumors are sporadic. Therefore, the identification of MSI/dMMR requires additional diagnostic tools to identify LS. In this review, we address the hallmarks of LS and present recent advances in diagnostic and screening strategies to identify LS patients. We also discuss the pitfalls associated with current strategies, which should be taken into account in order to improve the diagnosis of LS.

Abstract

Microsatellite instability (MSI) is a hallmark of Lynch syndrome (LS)-related tumors but is not specific to it, as approximately 80% of MSI/mismatch repair-deficient (dMMR) tumors are sporadic. Methods leading to the diagnosis of LS have considerably evolved in recent years and so have tumoral tests for LS screening and for the discrimination of LS-related to MSI-sporadic tumors. In this review, we address the hallmarks of LS, including the clinical, histopathological, and molecular features. We present recent advances in diagnostic and screening strategies to identify LS patients. We also discuss the pitfalls associated with the current strategies, which should be taken into account to improve the diagnosis of LS and avoid inappropriate clinical management.

How Should We Test for Lynch Syndrome? A Review of Current Guidelines and Future Strategies

International guidelines for the diagnosis of Lynch syndrome (LS) recommend molecular screening of colorectal cancers (CRCs) to identify patients for germline mismatch repair (MMR) gene testing. As our understanding of the LS phenotype and diagnostic technologies have advanced, there is a need to review these guidelines and new screening opportunities. We discuss the barriers to implementation of current guidelines, as well as guideline limitations, and highlight new technologies and knowledge that may address these. We also discuss alternative screening strategies to increase the rate of LS diagnoses. In particular, the focus of current guidance on CRCs means that approximately half of Lynch-spectrum tumours occurring in unknown male LS carriers, and only one-third in female LS carriers, will trigger testing for LS. There is increasing pressure to expand guidelines to include molecular screening of endometrial cancers, the most frequent cancer in female LS carriers. Furthermore, we collate the evidence to support MMR deficiency testing of other Lynch-spectrum tumours to screen for LS. However, a reliance on tumour tissue limits preoperative testing and, therefore, diagnosis prior to malignancy. The recent successes of functional assays to detect microsatellite instability or MMR deficiency in non-neoplastic tissues suggest that future diagnostic pipelines could become independent of tumour tissue.

Panel gene profiling of small bowel adenocarcinoma: Results from the NADEGE prospective cohort

Small bowel adenocarcinoma (SBA) is a rare tumour. Large genomic analyses with prognostic assessments are lacking. The NADEGE cohort has enrolled 347 patients with all stage SBA from 2009 to 2012. Next-generation sequencing investigates the presence of 740 hotspot somatic mutations in a panel of 46 genes involved in carcinogenesis. The mismatch repair (MMR) status was assessed by immunochemistry. We have collected 196 tumour samples and 125 had conclusive results for mutation analysis. The number of mutations was 0 in 9.6% of tumours, only 1 in 32.0%, 2 in 26.4% and ≥3 in 32.0%. Overall, at least one genomic alteration was observed in 90.4% of tumour. The most frequent genomic alteration was in KRAS (44.0%), TP53 (38.4%), PIK3CA (20.0%), APC (18.4%), SMAD4 (14.4%) and ERBB2 (7.2%) genes. KRAS mutations were more frequent in synchronous metastatic tumours than in localised tumours (72.7% vs 38.2%, P = .003). There was no significant difference in the mutation rates according to primary location for the most frequently altered gene. ATM, FGFR3 and FGFR1 gene alterations were associated with Lynch syndrome and IDH1 mutations with Crohn disease. dMMR tumours were associated with younger age, localised tumours, less KRAS but more SMARCB1 mutations. No genomic alteration was associated with overall survival. There is a trend for better survival in patient with dMMR tumours. In conclusion, there is a different genomic alteration profile in SBA according to predisposing diseases. No association between genomic alterations and prognoses was observed except for a trend of better prognoses associated with dMMR.

Characterization and Clinical Outcomes of DNA Mismatch Repair-deficient Small Bowel Adenocarcinoma

PURPOSE

The prevalence and clinical characteristics of small bowel adenocarcinomas (SBA) in the setting of Lynch syndrome have not been well studied. We characterized SBA according to DNA mismatch repair and/or microsatellite instability (MMR/MSI) and germline mutation status and compared clinical outcomes.

EXPERIMENTAL DESIGN

A single-institution review identified 100 SBAs. Tumors were evaluated for MSI via MSIsensor and/or corresponding MMR protein expression via IHC staining. Germline DNA was analyzed for mutations in known cancer predisposition genes, including MMR (MLH1, MSH2, MSH6, PMS2, and EPCAM). Clinical variables were correlated with MMR/MSI status.

RESULTS

Twenty-six percent (26/100; 95% confidence interval, 18.4-35.4) of SBAs exhibited MMR deficiency (MMR-D). Lynch syndrome prevalence was 10% overall and 38.5% among MMR-D SBAs. Median age at SBA diagnosis was similar in non-Lynch syndrome MMR-D versus MMR-proficient (MMR-P) SBAs (65 vs. 61; P = 0.75), but significantly younger in Lynch syndrome (47.5 vs. 61; P = 0.03). The prevalence of synchronous/metachronous cancers was 9% (6/67) in MMR-P versus 34.6% (9/26) in MMR-D SBA, with 66.7% (6/9) of these in Lynch syndrome (P = 0.0002). In the MMR-P group, 52.2% (35/67) of patients presented with metastatic disease, compared with 23.1% (6/26) in the MMR-D group (P = 0.008). In MMR-P stage I/II patients, 88.2% (15/17) recurred, compared with 18.2% (2/11) in the MMR-D group (P = 0.0002).

CONCLUSIONS

When compared with MMR-P SBA, MMR-D SBA was associated with earlier stage disease and lower recurrence rates, similar to observations in colorectal cancer. With a 38.5% prevalence in MMR-D SBA, germline Lynch syndrome testing in MMR-D SBA is warranted.

Beyond bevacizumab: a review of targeted agents in metastatic small bowel adenocarcinoma

Small bowel cancers are rare tumors with an incidence 50-100-fold less than colorectal cancer. These tumors carry a poor prognosis. Owing to its rarity, treatment of this disease, particularly in its advanced stages, has not been optimized and is derived mainly from treatment regimens for colorectal cancer. Based on recent studies bevacizumab, an antibody directed against vascular endothelial growth factor and used in the management of metastatic CRC, has been added to treatment guidelines for metastatic small bowel adenocarcinoma. We investigate in this review the evidence behind other targeted treatments that may be beneficial in the treatment of metastatic small bowel adenocarcinoma. These are agents against EGFR, VEGFR-2, HER2, and NTRK as well as immune checkpoint inhibitors. The last class of drugs appears to hold the greatest promise based on the preponderance of evidence supporting its use. However, overall data remains sparse. Results of studies currently underway will be valuable in shedding more light on the management of this aggressive cancer.

Prevalence and Molecular Characterization of Defective DNA Mismatch Repair in Small-bowel Carcinoma in a Japanese Hospital-based Population

Objectives

To investigate the prevalence and molecular characteristics of defective DNA mismatch repair (dMMR) in small-bowel carcinoma (SBC) in a Japanese-hospital population.

Methods

Immunohistochemistry was performed to evaluate the expression of MMR proteins (MLH1, MSH2, MSH6, and PMS2) in formalin-fixed paraffin-embedded sections prepared from surgically resected primary SBCs from 30 patients during March 2002 to March 2017. Genetic testing for Lynch syndrome was performed in patients who demonstrated MMR protein loss.

Results

Two of 30 patients (6.7%) demonstrated concomitant loss of MSH2/MSH6 protein expression. Further genetic testing identified a pathogenic MSH2 variant in one of these patients.

Conclusions

The prevalence of dMMR SBCs in a Japanese hospital-based population seems lower than that reported in previous studies. To determine whether dMMR SBCs might be strongly linked to Lynch syndrome, there is a need for further investigation with a larger sample size.

Frequency and clinicopathologic associations of DNA mismatch repair protein deficiency in ampullary carcinoma: Routine testing is indicated

BACKGROUND

The significance of DNA mismatch repair (MMR) deficiency in ampullary cancers (ACs) has not been established.

METHODS

In total, 127 ACs with invasive carcinomas measuring ≥3 mmthat had adequate tissue were analyzed immunohistochemically.

RESULTS

MMR loss was detected in 18% of ACs (higher than in colorectal cancers). Twelve tumors with MLH1-PMS2 loss were negative for BRAF V600E mutation, suggesting a Lynch syndrome association. MMR-deficient tumors (n = 23), comparedwith MMR-intact tumors (n = 104), showed a striking male predominance (male:female ratio, 4.7). Although the deficient tumors had slightly larger invasion size (2.7 vs 2.1 cm), they also had more expansile growth and less invasiveness, including less perineural invasion, and they ultimately had lower tumor (T) classification and less lymph node metastasis (30% vs 53%; P = .04). More important, patients who had MMR-deficient tumors had better clinical outcomes, with a 5-year overall survival rate of 68% versus 45% (P = .03), which was even more pronounced in those who had higher Tclassification (5-year overall survival, 69% vs 34%; P = .04). MMR deficiencyhad a statistically significant association with medullary phenotype, pushing-border invasion, and tumor-infiltrating immune cells, and it occurred more frequently in ampullary-duodenal type tumors. Programed cell death-ligand 1 (PD-L1) levels analyzed in the 22 MMR-deficient ACs revealed that all medullary carcinomas were positive. Nonmedullary MMR-deficient carcinomas expressed PD-L1 in 33% of tumors cells according to the criteria for a combined positive score ≥1, but all were negative according to the tumor proportion score≥1 method.

CONCLUSIONS

In ACs, MMR deficiency is even more frequent (18%) than in colon cancer and often has a Lynch-suggestive profile, thus routine testing is warranted. Male gender, pushing-border infiltration, ampullary-duodenal origin, medullary histology, and tumor-related inflammation have a significantly higher association with MMR deficiency. MMR-deficient tumors have less aggressive behavior. PD-L1 expression is common in medullary-phenotype ACs, thus immunotherapy should be considered at least for this group.

Prognostic Role of Mismatch Repair Status, Histotype and High-Risk Pathologic Features in Stage II Small Bowel Adenocarcinomas

BACKGROUND

Small bowel adenocarcinoma is a relatively rare cancer, often diagnosed in an advanced stage. In localized and resectable disease, surgery alone or in combination with adjuvant chemotherapy is the mainstay of treatment. In the recently published National Comprehensive Cancer Network Clinical Practice guidelines, criteria for selecting patients with stage II small bowel adenocarcinoma to receive adjuvant chemotherapy are provided, and they are mainly extrapolated from studies on colorectal cancer.

PATIENTS AND METHODS

In the present study, we aimed to verify whether mismatch repair deficiency phenotype, high-risk pathologic features (including T4, positive resection margins and a low number of lymph nodes harvested), as well as tumor histologic subtype, were associated with cancer-specific survival in 66 stage II non-ampullary small bowel adenocarcinoma patients, collected through the Small Bowel Cancer Italian Consortium. A central histopathology review was performed. Mismatch repair deficiency was tested by immunohistochemistry for MLH1, MSH2, MSH6 and PMS2, and confirmed by polymerase chain reaction for microsatellite instability.

RESULTS

We identified mismatch repair deficiency, glandular/medullary histologic subtype, and celiac disease as significant predictors of favorable cancer-specific survival using univariable analysis with retained significance in bivariable models adjusted for pT stage. Among the high-risk features, only T4 showed a significant association with an increased risk of death; however, its prognostic value was not independent of mismatch repair status.

CONCLUSIONS

Mismatch repair protein expression, histologic subtype, association with celiac disease, and, in the mismatch repair proficient subset only, T stage, may help identify patients who may benefit from adjuvant chemotherapy.

Addition of Bevacizumab to First-Line Palliative Chemotherapy in Patients with Metastatic Small Bowel Adenocarcinoma: A Population-Based Study

BACKGROUND

Data about the use and effectiveness of targeted therapy in metastatic small bowel adenocarcinoma (SBA) are scarce.

OBJECTIVE

The aim of this population-based study was to obtain insights into the use and effectiveness of targeted therapy in patients with synchronous metastases of SBA.

PATIENTS AND METHODS

Data were retrieved from the Netherlands Cancer Registry. Patients treated with palliative chemotherapy and/or targeted therapy for synchronous metastatic SBA between 2007 and 2016 were included (n = 187). Differences in treatment and the subsequent effects on overall survival (OS) were evaluated.

RESULTS

In first-line treatment, 25 patients (13%) received additional targeted therapy, exclusively bevacizumab, and mostly in combination with CAPOX/FOLFOX (n = 24). A primary ileal tumour was predictive for receiving bevacizumab in first-line treatment (odds ratio 3.2, 95% confidence interval (CI) 1.06-9.93). Median OS for patients in whom bevacizumab was added to first-line chemotherapy was 9.3 months, compared to 9.1 months with chemotherapy only (p = 0.85). Median OS for patients receiving first-line treatment only was 8.5 months with and 6.4 months without the addition of bevacizumab, respectively (p = 0.54). In multivariable survival analyses, the addition of bevacizumab was no prognostic factor (hazard ratio 1.01, 95% CI 0.65-1.59).

CONCLUSIONS

Bevacizumab was the only prescribed targeted therapy in first-line treatment. Considering the limited number of patients receiving first-line bevacizumab and the unknown reasons to prescribe additional targeted therapy, the corresponding survival rates of patients treated with and without additional bevacizumab in first-line treatment might suggest a limited clinical effect of bevacizumab in addition to first-line palliative chemotherapy on OS. Future research should focus on identifying the subgroup of patients who might benefit from anti-VEGF therapy in metastatic SBA.

Prognostic relevance of programmed death-ligand 1 expression and microsatellite status in small bowel adenocarcinoma

Background: Small bowel adenocarcinoma (SBA) is a dreadful disease. Patient prognosis is limited due to late presentation and ineffective chemotherapy. PD-1/PD-L1 checkpoint immunotherapy is regarded as a promising approach in several cancer entities. The association of PD-1/PD-L1 expression and its impact on patient prognosis with SBA is unclear. Material and methods: Seventy-five consecutive patients who underwent surgery for SBA were retrospectively analyzed and stained for PD-L1 expression in the tumour or the stroma. Analysis of mismatch repair genes was performed to determine microsatellite status. Kaplan-Meier estimate was used to analyze patient survival. Univariate and multivariable Cox regression-analyses were used to assess the impact of PD-L1 expression and microsatellite status on patient survival.Results: PD-L1 was weakly upregulated within the tumour or the stroma and associated with prolonged survival (p = .0071 and p = .0472, respectively). Fifty-one tumours (68%) revealed microsatellite stability (MSS) and 24 tumours (32%) were microsatellite instable (MSI) without correlating with patient survival (p = .611). Neither PD-L1 expression in the tumour nor in the stroma was identified as an independent risk factor influencing survival (p = .572 and p = .3055).Conclusion: Although PD-L1 expression is associated with prolonged survival, it was not identified as an independent prognostic marker. Microsatellite status did not influence long-term survival.

Small bowel adenocarcinoma: Results from a nationwide prospective ARCAD-NADEGE cohort study of 347 patients

Small bowel adenocarcinoma (SBA) is a rare tumour. We conducted a prospective cohort to describe the prevalence, survival and prognostic factors in unselected SBA patients. The study enrolled patients with all stages of newly diagnosed or recurrent SBA at 74 French centres between January 2009 and December 2012. In total, 347 patients were analysed; the median age was 63 years (range 23-90). The primary tumour was in the duodenum (60.6%), jejunum (20.7%) and ileum (18.7%). The prevalence of predisposing disease was 8.7%, 6.9%, 1.7%, 1.7% and 0.6% for Crohn disease, Lynch syndrome, familial adenomatous polyposis, celiac disease and Peutz-Jeghers syndrome, respectively. At diagnosis, 58.9%, 5.5% and 35.6% of patients had localised and resectable, locally advanced unresectable and metastatic disease, respectively. Crohn disease was significantly associated with younger age, poor differentiation and ileum location, whereas Lynch syndrome with younger age, poor differentiation, early stage and duodenum location. Adjuvant chemotherapy (oxaliplatin-based in 89.9%) was performed in 61.5% of patients with locally resected tumours. With a 54-months median follow-up, the 5-year overall survival (OS) was 87.9%, 78.2% and 55.5% in Stages I, II and III, respectively. The median OS of patients with Stage IV was 12.7 months. In patients with resected tumours, poor differentiation (p = 0.047) and T4 stage (p = 0.001) were associated with a higher risk of death. In conclusion, our study showed that the prognosis of advanced SBA remains poor. Tumour characteristics differed according to predisposing disease. In SBA-resected tumours, the prognostic factors for OS were grade and T stage.

Molecular alterations and PD-L1 expression in non-ampullary duodenal adenocarcinoma: Associations among clinicopathological, immunophenotypic and molecular features

Non-ampullary duodenal adenocarcinoma (NADC) is extremely rare. Little is known about its clinicopathological and molecular features or its management. Herein we retrospectively analyzed the cases of 32 NADC patients, focusing on microsatellite instability (MSI), genetic mutations, CpG island methylator phenotype (CIMP), and immunostaining including mucin phenotype and PD-L1 expression. The incidence of MSI, KRAS/BRAF/GNAS mutations and CIMP was 51.6%, 34.4%/3.1%/6.5% and 28.1%, respectively. PD-L1 expression was seen in 34.4% of patients. No significant associations between clinicopathological features and KRAS/BRAF/GNAS genetic mutations or CIMP were found. Histologically non-well-differentiated-type NADCs and those in the 1st portion of the duodenum were significantly associated with later stages (stages III–IV) (P = 0.006 and P = 0.003, respectively). Gastric-phenotype NADCs were frequently observed in the 1st portion and in late-stage patients; their cancer cells more frequently expressed PD-L1. Histologically, the non-well-differentiated type was an independent predictor of PD-L1 expression in cancer cells (OR 25.05, P = 0.04) and immune cells (OR 44.14, P = 0.02). Only late-stage disease (HR 12.23, P = 0.01) was a prognostic factor for worse overall survival in a Cox proportional hazards regression model. Our observation of high proportions of MSI and PD-L1 expression may prompt the consideration of immune checkpoint inhibitors as a new treatment option for NADCs.

Off-label use of common predictive biomarkers in gastrointestinal malignancies: a critical appraisal

The use of immunohistochemistry (IHC) as a companion diagnostic is an increasingly important part of the case workup by pathologists and is often central to clinical decision making. New predictive molecular markers are constantly sought for to improve treatment stratification parallel to drug development. Unfortunately, official biomarker guidelines lag behind, and pathologists are often left hesitating when medical oncologists request off-labelled biomarker testing. We performed a literature review of five commonly requested off-label IHC predictive biomarkers in gastrointestinal tract (GIT) malignancies: HER2, mismatch repair (MMR), PD-L1, BRAF V600E and ROS1. We found that HER2 amplification is rare and poorly associated to IHC overexpression in extracolonic and extragastric GIT cancers; however in KRAS wild type colorectal cancers, which fail conventional treatment, HER2 IHC may be useful and should be considered. For MMR testing, more evidence is needed to recommend reflex testing in GIT cancers for treatment purposes. MMR testing should not be discouraged in patients considered for second line checkpoint inhibitor therapy. With the exception of gastric tumors, PD-L1 IHC is a weak predictor of checkpoint inhibitor response in the GIT and should be replaced by MMR in this context. BRAF inhibitors showed activity in BRAF V600E mutated cholangiocarcinomas and pancreatic carcinomas in non-first line settings. ROS1 translocation is extremely rare and poorly correlated to ROS1 IHC expression in the GIT; currently there is no role for ROS1 IHC testing in GIT cancers. Overall, the predictive biomarker literature has grown exponentially, and official guidelines need to be updated more regularly to support pathologists’ testing decisions.

Bevacizumab in metastatic small-bowel adenocarcinoma: A systematic review and meta-analysis

Cancers of the small bowel could account for less than 5% of all gastrointestinal malignancies. Of these tumors, adenocarcinomas were the major histologic subtype and generally carried a poor prognosis. High expression of vascular epithelial growth factor (VEGF) could be seen in small bowel adenocarcinomas. A systematic review was conducted here to determine if bevacizumab, a recombinant humanized antibody against VEGF, could offer clinical benefit among patients with metastatic small bowel adenocarcinoma when combined with chemotherapy. A search for relevant published and unpublished studies was performed using PubMed, ScienceDirect, Google Scholar, the American Society of Clinical Oncology meetings library, ClinicalTrials.gov, and ISRCTN registry. Information on study design, methods, intervention, and outcomes were extracted from selected eligible studies. Methodological quality was then assessed using the Newcastle-Ottawa Scale. There was a significant improvement in mean overall survival with the addition of bevacizumab with chemotherapy versus chemotherapy alone. The use of bevacizumab with chemotherapy, likewise improved progression-free survival and objective response rate compared to chemotherapy alone. Continued use of bevacizumab beyond first progression also appeared to show benefit. The conduct of prospective controlled studies by consortia to offset the rarity of small bowel adenocarcinomas could further elucidate the efficacy of bevacizumab in the treatment of this disease.

DNA Mismatch Repair Deficiency and Immune Checkpoint Inhibitors in Gastrointestinal Cancers

In the recent few years, significant efforts have been undertaken for the development of different immunotherapeutic approaches against cancer. In this context, immune checkpoint inhibitors (ICIs), a novel class of immunotherapeutic drugs with the potential to unleash the immune system, have emerged as authentic game-changers for managing patients with various cancers, including gastrointestinal malignancies. Although the majority of gastrointestinal cancers are generally considered poorly immunogenic, basic research findings and data from clinical trials have proven that subset(s) of patients with various digestive tract cancers are highly responsive to ICI-based therapy. In this context, a better understanding on the role of various DNA repair pathway alterations, especially the evidence supporting the significant importance of DNA mismatch repair deficiencies and the efficacy of the anti-programmed cell death 1 drugs, have led to US Food and Drug Administration approval of 2 anti-programmed cell death 1 antibodies (pembrolizumab and nivolumab) for the treatment of patients with microsatellite instability. This review aims to provide a comprehensive and up-to-date summary for the role of DNA mismatch repair deficiency in cancer, and its importance in the development of ICI therapy. In addition, we provide insights into the spectrum of various genetic alterations underlying ICI resistance, together with the important influence that the tumor microenvironment plays in mediating the therapeutic response to this new class of drugs. Finally, we provide a comprehensive yet succinct glimpse into the most exciting preclinical discoveries and ongoing clinical trials in the field, highlighting bench-to-beside translational impact of this exciting area of research.

Molecular Diagnostics in the Neoplasms of Small Intestine and Appendix: 2018 Update

Neoplasms of the small intestine are rare in comparison with colorectal tumors. The most common tumor types arising in the small intestine are adenocarcinomas, well-differentiated neuroendocrine tumors, gastrointestinal stromal tumors, and lymphoma. Primary appendiceal neoplasms are rare and found in less than 2% of appendectomy specimens with an incidence of approximately 1.2 cases per 100,000 people per year in the United States. This article explores molecular diagnostics in the neoplasms of small intestine and appendix.

Alterations in ERBB2 and BRCA and microsatellite instability as new personalized treatment options in small bowel carcinoma

BACKGROUND

Carcinomas of the small bowel are rare tumors usually with dismal prognosis. Most recently, some potentially treatable molecular alterations were described. We emphasize the growing evidence of individualized treatment options in small bowel carcinoma.

METHODS

We performed a DNA- based multi-gene panel using ultra-deep sequencing analysis (including 14 genes with up to 452 amplicons in total; KRAS, NRAS, HRAS, BRAF, DDR2, ERBB2, KEAP1, NFE2L2, PIK3CA, PTEN, RHOA, BRCA1, BRCA2 and TP53) as well as an RNA-based gene fusion panel including ALK, BRAF, FGFR1, FGFR2, FGFR3, MET, NRG1, NTRK1, NTRK2, NTRK3, RET and ROS1 on eleven formalin fixed and paraffin embedded small bowel carcinomas. Additionally, mismatch-repair-deficiency was analyzed by checking the microsatellite status using the five different mononucleotide markers BAT25, BAT26, NR-21, NR-22 and NR-27 and loss of mismatch repair proteins using four different markers (MLH1, MSH6, MSH2, PMS2).

RESULTS

In five out of eleven small bowel carcinomas we found potentially treatable genetic alterations. Three patients demonstrated pathogenic (class 5) BRCA1 or BRCA2 mutations - one germline-related in a mixed neuroendocrine-non neuroendocrine neoplasm (MiNEN). Two additional patients revealed an activating ERBB2 mutation or PIK3CA mutation. Furthermore two tumors were highly microsatellite-instable (MSI-high), in one case associated to Lynch-syndrome. We did not find any gene fusions.

CONCLUSION

Our results underscore, in particular, the relevance of potentially treatable molecular alterations (like ERBB2, BRCA and MSI) in small bowel carcinomas. Further studies are needed to proof the efficacy of these targeted therapies in small bowel carcinomas.

Small Bowel Carcinomas Associated with Immune-Mediated Intestinal Disorders: The Current Knowledge

Small bowel carcinomas (SBC) are uncommon neoplasms, whose predisposing conditions include hereditary syndromes and immune-mediated intestinal disorders including coeliac disease (CD) and Crohn's disease (CrD). Although both CD-associated SBC (CD-SBC) and CrD-associated SBC (CrD-SBC) arise from an inflammatory background, they differ substantially in tumour cell phenotype, frequency of microsatellite instability and nuclear β-catenin expression, as well as in prognosis. For these patients, high tumour-infiltrating lymphocyte density and glandular/medullary histotype represent independent positive prognostic factors. Dysplasia adjacent to SBC is rare and characterized by intestinal phenotype and nuclear β-catenin in CD, while it is frequent and typified by gastro-pancreatobiliary marker expression and preserved membranous β-catenin in CrD. Recent evidence suggests that Epstein-Barr virus-positive dysplasia and SBC, albeit exceptional, do exist and are associated with CrD. In this review, we summarize the novel pathological and molecular insights of clinical and therapeutic interest to guide the care of CD-SBC and CrD-SBC.

ERBB3-Activating Mutations in Small Bowel Adenocarcinomas

Purpose

Functional studies have demonstrated that some mutations of ERBB3, which encodes for human epidermal growth factor receptor (HER) 3, are oncogenic via activation of the ErbB family signaling pathway. Significant clinical activity of anti-HER2 therapies (trastuzumab plus lapatinib combination or afatinib) has been reported in patients with ERBB3-mutated cancers. This study was designed to report the rate of activating ERBB3 mutations in small bowel adenocarcinoma (SBA), a rare tumor type in which we previously reported a high rate (12%) of ERBB2-activating mutations.

Materials and Methods

DNA from 74 SBAs, previously characterized for ERBB2 mutations and mismatch repair status, was submitted for sequencing of ERBB3 exons 3, 6, 7, 8, and 23. Orthogonal validation by targeted next-generation sequencing was performed.

Results

Four of 74 SBAs (5.4%) displayed ERBB3-activating mutations, including three p.V104M mutations (c.310 G>A) in exon 3 and one p.E928G mutation (c.2783 A>G) in exon 23. No mutations were detected in exons 6, 7, and 8. ERBB3-activating mutations were associated with microsatellite instability ( P = .002) and the presence of ERBB2-activating mutations ( P = .002). Two SBAs with co-occurrence of ERBB2 and ERBB3 mutations were further analyzed by targeted next-generation sequencing. Mutant allelic frequencies suggested that both mutations were shared by the same clone rather than being harbored by mutually exclusive tumor subclones.

Conclusion

SBAs display a high rate of ERBB3-activating mutations, which have been shown to be targetable by anti-HER2 therapies. Strikingly, ERBB3 was frequently comutated with ERBB2, suggesting a strong oncogenic addiction of these SBAs to the HER2 pathway.

DNA Sequencing of Small Bowel Adenocarcinomas Identifies Targetable Recurrent Mutations in the ERBB2 Signaling Pathway

PURPOSE

Little is known about the genetic alterations characteristic of small bowel adenocarcinoma (SBA). Our purpose was to identify targetable alterations and develop experimental models of this disease.Experimental Design: Whole-exome sequencing (WES) was completed on 17 SBA patient samples and targeted-exome sequencing (TES) on 27 samples to confirm relevant driver mutations. Two SBA models with ERBB2 kinase activating mutations were tested for sensitivity to anti-ERBB2 agents in vivo and in vitro. Biochemical changes were measured by reverse-phase protein arrays.

RESULTS

WES identified somatic mutations in 4 canonical pathways (WNT, ERBB2, STAT3, and chromatin remodeling), which were validated in the TES cohort. Although APC mutations were present in only 23% of samples, additional WNT-related alterations were seen in 12%. ERBB2 mutations and amplifications were present in 23% of samples. Patients with alterations in the ERBB2 signaling cascade (64%) demonstrated worse clinical outcomes (median survival 70.3 months vs. 109 months; log-rank HR = 2.4, P = 0.03). Two ERBB2-mutated (V842I and Y803H) cell lines were generated from SBA patient samples. Both demonstrated high sensitivity to ERBB2 inhibitor dacomitinib (IC₅₀ < 2.5 nmol/L). In xenografts derived from these samples, treatment with dacomitinib reduced tumor growth by 39% and 59%, respectively, whereas it had no effect in an SBA wild-type ERBB2 model.

CONCLUSIONS

The in vitro and in vivo models of SBA developed here provide a valuable resource for understanding targetable mutations in this disease. Our findings support clinical efforts to target activating ERBB2 mutations in patients with SBA that harbor these alterations.

Small Bowel Adenocarcinoma

Small bowel adenocarcinoma is a clinically and anatomically distinct gastrointestinal cancer that lacks prospective data to support its optimal management. Patients with inflammatory bowel disease and inherited conditions that cause gastrointestinal polyps are at especially high risk. Due to a lack of effective surveillance programs resulting in missed or delayed diagnoses only when symptoms develop, this disease is generally discovered at an advanced stage. Surgical resection is the only treatment modality with a chance of cure. Currently accepted treatment considerations are often generalized from large bowel and pancreatic-biliary cancers, due to some anatomic and clinical parallels. Additional research, however, is desperately needed to characterize the unique molecular differences of this disease to better prognosticate patients and establish rational clinical trials that would improve their outcomes.

Patient with Lynch syndrome with subsequent development of small bowel adenocarcinoma

Small bowel adenocarcinoma (SBA) is a rare cancer in the general population, but the incidence increases in patients with Lynch syndrome. The present case describes a 57-year-old white woman with a history of colon cancer status posthemicolectomy and diagnosis of Lynch syndrome. Twenty years after her operation, the patient presented with vague abdominal discomfort and constipation, and underwent an exploratory laparotomy which revealed a stage 3A SBA. Genetic testing of the specimen provided evidence of microsatellite instability and faulty DNA repair supporting aetiology of Lynch syndrome. This case is unique in that SBA, if present in patients with Lynch syndrome, is usually a presenting symptom and has not been widely described in literature as an occurrence so many years after. As a result, this case highlights the importance of a low threshold for a thorough evaluation in patients with Lynch syndrome who present with signs of small bowel obstruction.