Lifestyle factors and small intestine adenocarcinoma risk: A systematic review and meta-analysis

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.

Gastrointestinal tract pathology of the owl monkey (Aotus spp.)

Owl monkeys are small nocturnal new world primates in the genus Aotus that are most used in biomedical research for malaria. Cardiomyopathy and nephropathy are well-described common diseases contributing to their morbidity and mortality; less is known about lesions affecting the gastrointestinal tract. Records from a 14-year period (2008-2022) at the Keeling Center for Comparative Medicine and Research were queried to identify instances of spontaneous gastrointestinal disease that directly contributed to the cause of death from the 235 adult owl monkeys submitted for necropsy. Of the 235, 10.6% (25/235) had gastrointestinal disease listed as a significant factor that contributed to morbidity and mortality. Diagnoses included candidiasis (3/25), gastric bloat (4/25), and intestinal incarceration and ischemia secondary (11/25), which included intussusception (4/25), mesenteric rent (3/25), strangulating lipoma (2/25), intestinal torsion (1/25), and an inguinal hernia (1/25). Intestinal adenocarcinomas affecting the jejunum (4/25) were the most common neoplasia diagnosis. Oral squamous cell carcinoma (1/25) and intestinal lymphoma (2/25) were also diagnosed. This report provides evidence of spontaneous lesions in the species that contribute to morbidity and mortality.

Immune signature of small bowel adenocarcinoma and the role of tumor microenvironment

In this editorial we comment on the article published "Clinical significance of programmed cell death-ligand expression in small bowel adenocarcinoma is determined by the tumor microenvironment". Small bowel adenocarcinoma (SBA) is a rare gastrointestinal neoplasm and despite the small intestine's significant surface area, SBA accounts for less than 3% of such tumors. Early detection is challenging and the reason arises from its asymptomatic nature, often leading to late-stage discovery and poor prognosis. Treatment involves platinum-based chemotherapy with a 5-fluorouracil combination, but the lack of effective chemotherapy contributes to a generally poor prognosis. SBAs are linked to genetic disorders and risk factors, including chronic inflammatory conditions. The unique characteristics of the small bowel, such as rapid cell renewal and an active immune system, contributes to the rarity of these tumors as well as the high intratumoral infiltration of immune cells is associated with a favorable prognosis. Programmed cell death-ligand 1 (PD-L1) expression varies across different cancers, with potential discrepancies in its prognostic value. Microsatellite instability (MSI) in SBA is associated with a high tumor mutational burden, affecting the prognosis and response to immunotherapy. The presence of PD-L1 and programmed cell death 1, along with tumor-infiltrating lymphocytes, plays a crucial role in the complex microenvironment of SBA and contributes to a more favorable prognosis, especially in the context of high MSI tumors. Stromal tumor-infiltrating lymphocytes are identified as independent prognostic indicators and the association between MSI status and a favorable prognosis, emphasizes the importance of evaluating the immune status of tumors for treatment decisions.

Diet and lifestyle in relation to small intestinal cancer risk: findings from the European Prospective Investigation into Cancer and Nutrition (EPIC)

PURPOSE

The incidence of small intestinal cancer (SIC) is increasing, however, its aetiology remains unclear due to a lack of data from large-scale prospective cohorts. We examined modifiable risk factors in relation to SIC overall and by histological subtype.

METHODS

We analysed 450,107 participants enrolled in the European Prospective Investigation into Cancer and Nutrition cohort. Cox proportional hazards models were used to estimate univariable and multivariable hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During an average of 14.1 years of follow-up, 160 incident SICs (62 carcinoids, 51 adenocarcinomas) were identified. Whilst univariable models revealed a positive association for current versus never smokers and SIC (HR, 95% CI: 1.77, 1.21-2.60), this association attenuated in multivariable models. In energy-adjusted models, there was an inverse association across vegetable intake tertiles for SIC overall (HRT3vsT1, 95% CI: 0.48, 0.32-0.71, p-trend: < 0.001) and for carcinoids (HRT3vsT1, 95% CI: 0.44, 0.24-0.82, p-trend: 0.01); however, these attenuated in multivariable models. Total fat was also inversely associated with total SIC and both subtypes but only in the second tertile (SIC univariable HRT2vsT1, 95% CI: 0.57, 0.38-0.84; SIC multivariable HRT2vsT1, 95% CI: 0.55, 0.37-0.81). Physical activity, intake of alcohol, red or processed meat, dairy products, or fibre were not associated with SIC.

CONCLUSION

These exploratory analyses found limited evidence for a role of modifiable risk factors in SIC aetiology. However, sample size was limited, particularly for histologic subtypes; therefore, larger studies are needed to delineate these associations and robustly identify risk factors for SIC.

Incidence, Risk Factors, and Temporal Trends of Small Intestinal Cancer: A Global Analysis of Cancer Registries

BACKGROUND & AIMS

Small intestinal cancer is a rare cancer, with limited studies exploring its epidemiology. To our knowledge, this study is the first effort to comprehensively analyze the incidence, risk factors, and trends for small intestinal cancer by sex, age, and country.

METHODS

Global Cancer Observatory, Cancer Incidence in Five Continents Plus, and Global Burden of Disease were accessed to estimate the age-standardized rates of small intestinal cancer incidence (International Classification of Diseases, 10th Revision, Clinical Modification: C17) and prevalence of lifestyle risk factors, metabolic risk factors, and inflammatory bowel disease (IBD). Risk factor associations were assessed by linear and logistic regressions. Average annual percent change was calculated using joinpoint regression.

RESULTS

A total of 64,477 small intestinal cancer cases (age-standardized rate, 0.60 per 100,000) were estimated globally in 2020, with a higher disease burden found in North America (1.4). Higher small intestinal cancer incidence was associated with higher human development index; gross domestic product; and prevalence of smoking, alcohol drinking, physical inactivity, obesity, diabetes, lipid disorder, and IBD (β = 0.008-0.198; odds ratios, 1.07-10.01). There was an overall increasing trend of small intestinal cancer incidence (average annual percent change, 2.20-21.67), and the increasing trend was comparable among the 2 sexes but more evident in the older population aged 50-74 years than in the younger population aged 15-49 years.

CONCLUSION

There was a substantial geographic disparity in the burden of small intestinal cancer, with higher incidence observed in countries with higher human development index; gross domestic product; and prevalence of unhealthy lifestyle habits, metabolic disorders, and IBD. There was an overall increasing trend in small intestinal cancer incidence, calling for the development of preventive strategies.

Ileal adenocarcinoma in a young pregnant woman: A rare case report

Primary intestinal malignancies account for only 1%-3% of all malignant gastrointestinal tumors. Adenocarcinomas are uncommonly located in the ileum. Ileal adenocarcinoma (IA) is rare and difficult to diagnose because of its location. IA is common in older men and rare in young pregnant women. A 23-year-old pregnant woman was hospitalized several times for repeated vomiting and abdominal pain. Her symptoms were relieved after symptomatic treatment. She exhibited no typical manifestations of intestinal obstruction, such as abdominal distension, difficulty passing gas and defecation. Unfortunately, she was misdiagnosed with acute gastroenteritis. On the second day after delivery, the patient stopped passing gas and computed tomography (CT) revealed an intestinal obstruction. She was treated as paralytic ileus. However, in view of failed conservative management, she was decided for an exploratory laparotomy. A malignant ileal tumor 5cm from the ileocecal valve was found incidentally and was surgically excised accompanied with End-to-side anastomosis of ileal and transverse colon. The operation lasted 195 minutes. Pathological examination revealed an IA. Pregnant woman who experience symptoms of intestinal obstruction should be alert to the possibility of malignancy in the small intestine. IA is an insidious tumor in pregnant women. An "IA triad" can be defined as refractory vomiting, vague abdominal pain, and weight loss (or inadequate weight gain in pregnant women). Pregnant women with an IA triad should undergo investigation with endoscopy or, if necessary, magnetic resonance imaging (MRI).

Subsequent primary cancer risk among five-year survivors of adolescent and young adult cancers

BACKGROUND

A comprehensive examination of the incidence and mortality of subsequent primary cancers (SPCs) among adolescent and young adult (AYA) cancer survivors in the US is lacking.

METHODS

Cancer incidence and mortality among 170,404 ≥ 5-year cancer survivors aged 15-39 years at first primary cancer diagnosis during 1975-2013 in 9 Surveillance, Epidemiology, and End Results registries were compared to those in the general population using standardized incidence ratio (SIR), absolute excess incidence (AEI), standardized mortality ratio (SMR), and absolute excess mortality (AEM).

RESULTS

During a mean follow-up of 14.6 years, 13,420 SPC cases and 5,008 SPC deaths occurred among survivors (excluding the same-site as index cancer), corresponding to 25% higher incidence (95%CI = 1.23-1.27; AEI = 10.8 per 10,000) and 84% higher mortality (95%CI = 1.79-1.89; AEM = 9.2 per 10,000) than that in the general population. Overall SPC risk was statistically significantly higher for 20 of 29 index cancers for incidence and 26 for mortality, with the highest SIR among female Hodgkin lymphoma survivors (SIR = 3.05, 95%CI = 2.88-3.24; AEI = 73.0 per 10,000) and the highest SMR among small intestine cancer survivors (SMR = 6.97, 95%CI = 4.80-9.79; AEM = 64.1 per 10,000). Type-specific SPC risks varied substantially by index cancers; however, SPCs of the female breast, lung, and colorectum combined constituted 36% of all SPC cases and 39% of all SPC deaths, with lung cancer alone representing 11% and 24% of all cases and deaths, respectively.

CONCLUSION

AYA cancer survivors are almost twice as likely to die from a new primary cancer as the general population, highlighting the need for primary care clinicians to prioritize cancer prevention and targeted surveillance strategies in these individuals.

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).

Small Bowel Adenocarcinoma: a Nationwide Population-Based Study

PURPOSE

Small intestinal cancers have a non-specific clinical presentation and hence a delayed diagnosis. The prevalence of small intestinal cancers is low, and there are no cost-effective methods of screening. This study aimed to identify clinical characteristics of duodenal and jejunal adenocarcinomas that can assist in the early detection and diagnosis of disease.

METHODS

Duodenal adenocarcinoma and jejunal adenocarcinoma in Explorys database (1999-2019) were compared using odds ratio (OR) with 95% confidence intervals. Data on demographic characteristics, risk factors, clinical features, and treatment were collected.

RESULTS

Out of a total of 8100 patients with a diagnosis of primary adenocarcinoma of the small intestine, 5110 are primary adenocarcinoma of duodenum (63%), and 600 are primary adenocarcinoma of jejunum (7.4%). Patients with jejunal adenocarcinoma when compared with patients with duodenal adenocarcinoma are more obese (OR, 1.36) and have a significantly higher prevalence of malignant neoplasm of colon (OR, 3.07), Crohn's disease (OR, 4.42), and celiac disease (OR, 2.48). Jejunal adenocarcinoma patients presented more frequently with intestinal obstruction (OR, 1.99), whereas duodenal adenocarcinoma patients more commonly presented with iron deficiency anemia (OR, 0.16). Patients with jejunal adenocarcinoma are less likely to undergo therapy with anti-neoplastic agents when compared with duodenal adenocarcinoma (OR, 0.81). There are no differences in patients undergoing surgical intervention or a combination of surgical intervention and antineoplastic therapy.

CONCLUSIONS

Jejunal adenocarcinoma is more commonly associated with colorectal cancer, celiac disease, and Crohn's disease. They also had lower odds of requiring chemotherapeutic agents.

Adenocarcinoma of the fourth portion of duodenum presenting as intussusception: an unusual manifestation of rare pathology

Primary adenocarcinoma of the fourth portion of the duodenum (D-IV) is reported infrequently than other parts of the duodenum. Its diagnosis is often late because of non-specific symptoms and signs. We encountered a 48-year-old male patient who was diagnosed as duodeno-duodenal intussusception, underwent segmental duodenal resection with duodenojejunal anastomosis and confirmed as adenocarcinoma of D-IV. He received adjuvant chemotherapy and is doing well at 1 year of follow-up. This report describes about the rare case of isolated adenocarcinoma of the D-IV presented as intussusception which is never reported before and successfully treated by segmental resection of the duodenum and jejunum.

Metabolic factors and the risk of small intestine cancers: Pooled study of 800 000 individuals in the metabolic syndrome and cancer project

To explore the largely unknown etiology of small intestine cancer, we examined metabolic factors and risk of small intestine cancer overall and by subtypes. Among 404 220 women and 403 265 men in six European cohorts, we applied Cox regression with adjustment for smoking and body mass index (BMI), to calculate sex-specific hazard ratios (HRs) of small intestine cancer by levels of BMI, mean arterial pressure (MAP) and plasma total cholesterol, triglycerides and glucose. We also calculated HRs for these factors combined (metabolic score; MetS) and used Wald test statistics to investigate pairwise interactions between metabolic factors on risk. We also performed analyses separately per subtype (neuroendocrine tumors [NETs] and adenocarcinomas). During a median follow-up of 16.9 years, 144 women and 195 men were diagnosed with small intestine cancer, including 184 NETs and 99 adenocarcinomas. Among men, no main associations or interactions between metabolic factors were observed in relation to the risk of small intestine cancer. Among women, triglycerides were positively and linearly associated with risk (HR per standard deviation [SD]: 1.23, 95% confidence interval [CI]: 1.04-1.46), and a positive association was also observed for the MetS (HR per SD: 1.25, 95% CI: 1.02-1.52). Positive interactions were observed among women between triglycerides and cholesterol (P = .0005), and between MAP and glucose (P = .009), on risk. Glucose was positively associated with adenocarcinomas among women. This large, prospective study suggests that elevated triglycerides, and metabolic factors in interaction, confer an increased risk of small intestine cancer among women, but not among men.

Prognostic Value of Immune Environment Analysis in Small Bowel Adenocarcinomas with Verified Mutational Landscape and Predisposing Conditions

Background: Small bowel adenocarcinoma (SBA) is a rare yet insidious cancer with poor survival. The abundance of tumour-infiltrating lymphocytes is associated with improved survival, but the role of the programmed death-1/programmed death ligand-1 (PD-1/PD-L1) pathway in tumour escape is controversial. We evaluated immune cell infiltration, PD1/PD-L1 expression and their prognostic value in a series of SBAs with previously verified predisposing conditions and exome-wide somatic mutation characterization. Methods: Formalin-fixed paraffin-embedded tissue sections stained for CD3, CD8, PD-L1 and PD-1 were analysed from 94 SBAs. An immune cell score (ICS) was formed from the amount of the CD3 and CD8 positive lymphocytes from the tumour centre and invasive margin. The PD-L1 and PD-1 positive immune cells (ICs) and ICS were combined into a variable called Immunoprofile. Results: High ICS, PD-L1^IC and PD-1, individually and combined as Immunoprofile, were prognostic for better patient outcome. Sixty-five (69%) SBAs expressed ≥1% positive PD-L1^IC. A high tumour mutation burden was common (19%) and associated with immune markers. Immunoprofile, adjusted for TNM stage, mismatch repair status, tumour location, sex and age were independent prognostic markers for disease-specific and overall survival. Conclusions: Analysing tumoral immune contexture provides prognostic information in SBA. Combining ICS, PD-1 and PD-L1^IC as Immunoprofile enhanced the prognostic performance.

Misdiagnosis of multiple synchronous small bowel adenocarcinomas as intestinal tuberculosis: a case report

BACKGROUND

Small bowel adenocarcinoma (SBA) is a rare malignancy that primarily occurs in the duodenum. Multiple synchronous SBA is unique rare and difficult to diagnose due to non-specific disease presentation. Protocols to identify multiple synchronous SBA during early disease stages are urgently required.

CASE PRESENTATION

An elderly man experienced left lower abdominal pain and melena for 3 months. Abdominal CT showed thickening of the multiple segmental small intestinal walls. As the patient had pulmonary tuberculosis simultaneously, he was misdiagnosis as intestinal tuberculosis and received anti-spasm therapy. The treatment delayed radical resection surgery and the patient underwent palliative segmental resection of the jejunum after 4 months due to intestinal obstruction. Resected specimens showed multiple synchronous SBA (five tumors). The patient accepted chemotherapy postoperatively. Six months postoperatively, the patient died of brain metastasis.

CONCLUSIONS

We highlight how multiple synchronous SBA is rare and easily misdiagnosed. We should rule out multiple synchronous SBA when diagnosing intestinal diseases (e.g. inflammatory bowel disease, IBS). Intestinal tuberculosis may also be one of the risk factors for multiple synchronous SBA. High-risk patients should be assessed for known tumor makers, and receive gastroscopy, enteroscopy or capsule endoscopy. Doctors should obtain the pathology under endoscopy to the greatest possible degree. For suspected patients, laparotomy should be performed.

Trends in incidence of small bowel cancer according to histology: a population-based study

BACKGROUND

Small bowel cancer is not a single entity. Population-based studies taking into account histological diversity are scarce. The aim of this study was to report on their trends in incidence by histology in France over the past 20 years.

METHODS

All patients with a small bowel cancer diagnosed in 15 French administrative areas covered by a registry from the network of French cancer registries (FRANCIM) were included. Age-standardized incidence rates were estimated using the world standard population. Incidence rates were calculated by gender, age group, histology, and 5-year period.

RESULTS

The overall age-standardized incidence rates were 1.46/100,000 inhabitants in men and 0.9/100,000 inhabitants in women. Adenocarcinoma was the most common histological type (38%), followed by neuroendocrine tumors (35%), lymphoma (15%) and sarcoma (12%). Age at diagnosis and tumor location differed between adenocarcinoma and neuroendocrine tumors. The incidence of all four tumor types increased significantly over the 20-year period, with the exception of lymphoma in men. The annual percentage change for neuroendocrine tumors was 3.89% in men and 3.61% in women; for sarcoma, it was 3.38% and 4.08%, respectively. The incidence of adenocarcinoma and lymphoma also increased in women with an annual percentage change of 3.05% and 3.32%, respectively.

CONCLUSION

Small bowel cancer incidence has increased over time. This increase occurred with different amplitudes and patterns in the four major histological types. The improvement in imaging techniques could partly explain this increase. It is necessary to determine whether predisposing conditions may contribute to this change.

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.

Surgical Management of Jejunal Tumors: Experience from Tertiary Care Centre

INTRODUCTION

Small bowel is an uncommon site for primary neoplasm in the gastrointestinal tract. Traditionally, duodenum has been combined with jejunum and ileum in analysing the presentation and management of these tumors. Given the different presentation pattern, diagnostic difficulties and anatomical considerations, jejunal tumors may differ from duodenal tumors.

METHODOLOGY

Retrospective analysis of a prospectively maintained database of patients with histology proven jejunal tumors was done. Clinico-radiological characters, histological findings, surgical procedures and the outcomes in these patients were studied.

RESULTS

Sixteen patients were included in the study. Median age at presentation was 42 years (26-76 years) and majority were males (n = 11, 68.8%). Seven (43.7%) patients presented with emergencies. Endoscopic tissue diagnosis could be obtained in 5 (31.3%) patients. Histology of tumors were adenocarcinoma, gastrointestinal stromal tumor and lymphoma in 6 (37.5%), 5 (31.3%) and 3 (18.8%) respectively. Sarcoma (myxofibroma) and metastasis (urothelial origin) were present in one patient each. Two patients with adenocarcinoma had neoadjuvant chemotherapy. Curative resection was feasible in 14 patients. Resection of tumor-bearing segment with anastomosis was performed in 9 patients. Among these, 5 had duodenojejunostomy. One patient had resection and double-barrel jejunostomy. One patient with jejunal GIST had sleeve resection. Multi-visceral resection was performed in 3 patients. There were no mortality and median postoperative hospital stay was 11 days (range 7-33 days).

CONCLUSION

Histology spectrum of jejunal tumors are distinct. Difficulty in obtaining preoperative tissue diagnosis of these lesions need to be addressed by improved endoscopic and image-directed biopsy techniques.

Management of Advanced Small Bowel Cancer

OPINION STATEMENT

Small bower cancer is a rare disease, despite its incidence is increasing in the last decade. Both benign and malignant tumors can arise from the small intestine. The main histological cancer types are adenocarcinomas, neuroendocrine tumors, sarcomas, gastrointestinal stromal tumors (GISTs), and lymphomas. Due to the rarity of these malignances, all the currently available data are based on small studies or retrospective series, although recent breakthroughs are redirecting our approach to these patients. Immunotherapy for small bowel adenocarcinomas, several multikinase inhibitors in resistant GIST patients, as well as everolimus and ¹⁷⁷Lu-DOTATATE in neuroendocrine tumors are only few of the novel therapeutic options that have changed, or may change in the future, the therapeutic landscape of these rare cancers. Larger and more powerful studies on the molecular profile of these tumors may lead to a better design of clinical trials, which eventually would provide our patients with more efficacious treatments to improve both overall survival and quality of life.

Exome-wide somatic mutation characterization of small bowel adenocarcinoma

Small bowel adenocarcinoma (SBA) is an aggressive disease with limited treatment options. Despite previous studies, its molecular genetic background has remained somewhat elusive. To comprehensively characterize the mutational landscape of this tumor type, and to identify possible targets of treatment, we conducted the first large exome sequencing study on a population-based set of SBA samples from all three small bowel segments. Archival tissue from 106 primary tumors with appropriate clinical information were available for exome sequencing from a patient series consisting of a majority of confirmed SBA cases diagnosed in Finland between the years 2003–2011. Paired-end exome sequencing was performed using Illumina HiSeq 4000, and OncodriveFML was used to identify driver genes from the exome data. We also defined frequently affected cancer signalling pathways and performed the first extensive allelic imbalance (AI) analysis in SBA. Exome data analysis revealed significantly mutated genes previously linked to SBA (TP53, KRAS, APC, SMAD4, and BRAF), recently reported potential driver genes (SOX9, ATM, and ARID2), as well as novel candidate driver genes, such as ACVR2A, ACVR1B, BRCA2, and SMARCA4. We also identified clear mutation hotspot patterns in ERBB2 and BRAF. No BRAF V600E mutations were observed. Additionally, we present a comprehensive mutation signature analysis of SBA, highlighting established signatures 1A, 6, and 17, as well as U2 which is a previously unvalidated signature. Finally, comparison of the three small bowel segments revealed differences in tumor characteristics. This comprehensive work unveils the mutational landscape and most frequently affected genes and pathways in SBA, providing potential therapeutic targets, and novel and more thorough insights into the genetic background of this tumor type.

Small bowel adenocarcinoma is a rare but aggressive disease with limited treatment options. Of gastrointestinal tumors, small bowel tumors account for 3%, of which around one third are adenocarcinomas. Due to the scarcity of evidence-based treatment recommendations there is a dire need for knowledge on the biology of these tumors. Here, we performed the first large exome sequencing effort of 106 small bowel adenocarcinomas from a Finnish population-based cohort to comprehensively characterize the genetic background of this tumor type. The set included tumors from all three small bowel segments allowing us to also compare the genetic differences between these subsets. We defined significantly mutated genes and frequently affected pathways, providing potential therapeutic targets, such as BRAF, ERBB2, ERBB3, ERBB4, PIK3CA, KRAS, ATM, ACVR2A, ACVR1B, BRCA2, and SMARCA4, for this disease.

Multiple synchronous adenocarcinomas of the small bowel in a young patient: A case report

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This case report represents one of the youngest patients ever presented with this condition without any risk factors, and her follow up for three years.

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Multiple adenocarcinomas of the small bowel is an extremely rare disease with no standardized treatment.

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Its clinical presentation can vary from abdominal pain, mass, obstruction and bleeding, requiring a high index of suspicion.

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Its treatment is predominantly surgical and adjuvant therapies are now being studied in randomized controlled studies.

Introduction

Adenocarcinoma of the small bowel is a rare neoplasm presented usually in elder patients as a single tumor. Its presentation as multiple tumors and in young patients is exceptional and there aren't any guidelines to orient its therapy.

Presentation of case

We present the rare case of a sixteen-year-old woman that presents to the emergency department with an intussusception due to a small bowel tumor. The resected specimen showed multiple adenocarcinomas. A complete endoscopic and PET-CT study showed other 5 lesions from the duodenum to the ileum that were resected. Genetic counseling showed no pathogenic changes. The final staging was T2N0M0 and only surveillance was indicated. The patient is now 3 years without any recurrence.

Discussion

Multiple adenocarcinomas of the small bowel are a very infrequent presentation of the disease. Most common risk factors include Crohn disease and adenomas. Its presentation is usually vague with a delay in its diagnosis. The treatment remains mainly surgical with limited use of adjuvant therapy. The most important prognostic factor is lymph node involvement with 5-year survival that can range from 3%-60% depending on the stage.

Conclusion

This case represents an exceptional presentation of a very rare pathology with few cases described in the literature. There isn’t one single best study to stage the patient and surgery is still the standard of treatment while adjuvant therapies studies are being conducted. The young age and lack of predisposing factors or mutations leaves an open field for investigation.

Small Bowel Adenocarcinoma

Small bowel adenocarcinomas (SBAs) are rare tumors, but their incidence is increasing. The most common primary location is the duodenum. Even though SBAs are more often sporadic, some diseases are risk factors. Early diagnosis of small bowel adenocarcinoma remains difficult, despite significant radiologic and endoscopic progress. After R0 surgical resection, the main prognostic factor is lymph node invasion. An international randomized trial (BALLAD [Benefit of Adjuvant Chemotherapy For Small Bowel Adenocarcinoma] study) will evaluate the benefit of adjuvant chemotherapy. For metastatic disease, retrospectives studies suggest that platinum-based chemotherapy is the most effective treatment. Phase II studies are ongoing to evaluate targeted therapy in metastatic SBA.

A potential association between exposure to hepatitis B virus and small bowel adenocarcinoma

Chronic infection with hepatitis B virus (HBV) has never been described as a risk factor for small bowel adenocarcinoma, although infection is a known risk factor for hepatocellular carcinoma. From May 2009 to December 2014, we implemented an institution-wide screening program for hepatitis B viral serologies prior to starting chemotherapy. Evidence of exposure [hepatitis B core antibody (anti-HBc) positivity in the absence of hepatitis B surface antigen (HBsAg) positivity] was highest in patients with hepatocellular carcinoma (21.1%), followed by small bowel cancer (12.5%). The small bowel adenocarcinoma cases with anti-HBc positivity were reviewed. Special attention was paid to known risk factors for small bowel cancers. One patient had a diagnosis of hereditary nonpolyposis colorectal cancer (HNPCC). However, the other patients had no genetic syndromes, history of inflammatory bowel disease or other chronic inflammation to explain their risk. We postulate exposure to bile acids, tumorigenesis of hepatocytes and cholangiocytes, and/or damage to the intestinal mucosa secondary to HBV exposure/infection as potential mechanisms for development of small bowel adenocarcinoma. More research is warranted to further elucidate this association.