Incidence of, phenotypes of and survival from small bowel cancer in Denmark, 1994-2010: a population-based study

Risk factors, prognostic factors, and nomograms for distant metastasis in patients with diagnosed duodenal cancer: A population-based study

BACKGROUND

Duodenal cancer is one of the most common subtypes of small intestinal cancer, and distant metastasis (DM) in this type of cancer still leads to poor prognosis. Although nomograms have recently been used in tumor areas, no studies have focused on the diagnostic and prognostic evaluation of DM in patients with primary duodenal cancer.

AIM

To develop and evaluate nomograms for predicting the risk of DM and personalized prognosis in patients with duodenal cancer.

METHODS

Data on duodenal cancer patients diagnosed between 2010 and 2019 were extracted from the Surveillance, Epidemiology, and End Results database. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for DM in patients with duodenal cancer, and univariate and multivariate Cox proportional hazards regression analyses were used to determine independent prognostic factors in duodenal cancer patients with DM. Two novel nomograms were established, and the results were evaluated by receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

RESULTS

A total of 2603 patients with duodenal cancer were included, of whom 457 cases (17.56%) had DM at the time of diagnosis. Logistic analysis revealed independent risk factors for DM in duodenal cancer patients, including gender, grade, tumor size, T stage, and N stage (P < 0.05). Univariate and multivariate COX analyses further identified independent prognostic factors for duodenal cancer patients with DM, including age, histological type, T stage, tumor grade, tumor size, bone metastasis, chemotherapy, and surgery (P < 0.05). The accuracy of the nomograms was validated in the training set, validation set, and expanded testing set using ROC curves, calibration curves, and DCA curves. The results of Kaplan-Meier survival curves (P < 0.001) indicated that both nomograms accurately predicted the occurrence and prognosis of DM in patients with duodenal cancer.

CONCLUSION

The two nomograms are expected as effective tools for predicting DM risk in duodenal cancer patients and offering personalized prognosis predictions for those with DM, potentially enhancing clinical decision-making.

The Role of Capsule Endoscopy in the Diagnosis and Management of Small Bowel Tumors: A Narrative Review

Small bowel tumors (SBT) are relatively rare, but have had a steadily increasing incidence in the last few decades. Small bowel capsule endoscopy (SBCE) and device-assisted enteroscopy are the main endoscopic techniques for the study of the small bowel, the latter additionally providing sampling and therapeutic options, and hence acting complementary to SBCE in the diagnostic work-up. Although a single diagnostic modality is often insufficient in the setting of SBTs, SBCE is a fundamental tool to drive further management towards a definitive diagnosis. The aim of this paper is to provide a concise narrative review of the role of SBCE in the diagnosis and management of SBTs.

Non-Pure Intestinal Phenotype as an Indicator of Progression in Sporadic Nonampullary Duodenal Adenomas: A Multicenter Retrospective Cohort Study

INTRODUCTION

We aimed to evaluate the natural course of sporadic nonampullary duodenal adenomas (SNDAs) and determine the risk factors of progression.

METHODS

We retrospectively analyzed the follow-up outcomes of patients with biopsy-diagnosed SNDA between April 2010 and March 2016 at 13 institutions. All initial biopsy specimens were centrally evaluated. Only those diagnosed with adenomas were included. Mucinous phenotypes were classified into pure intestinal and non-pure intestinal phenotypes. Cumulative incidence rates of carcinoma and tumor enlargement were evaluated. Tumor enlargement was defined as a ≥25% or 5-mm increase in tumor size.

RESULTS

Overall, 121 lesions were analyzed. Within a median observation period of 32.7 months, 5 lesions were diagnosed as carcinomas; the cumulative 5-year incidence of carcinoma was 9.5%. Male sex ( P = 0.046), initial lesion size ≥10 mm ( P = 0.044), and non-pure intestinal phenotype ( P = 0.019) were significantly associated with progression to carcinoma. Tumor enlargement was observed in 22 lesions, with a cumulative 5-year incidence of 33.9%. Initial lesion size ≥10 mm ( P < 0.001), erythematous lesion ( P = 0.002), high-grade adenoma ( P = 0.002), Ki67 negative ( P = 0.007), and non-pure intestinal phenotype ( P = 0.001) were risk factors of tumor enlargement. In a multivariate analysis, an initial lesion size ≥10 mm ( P = 0.010) and non-pure intestinal phenotype ( P = 0.046) were independent and significant risk factors of tumor enlargement.

DISCUSSION

Lesion size ≥10 mm and non-pure intestinal phenotype on initial biopsy are risk factors of cancer progression and tumor enlargement in cases with SNDA. Thus, management effectiveness may be improved by focusing on lesion size and the mucinous phenotype.

An autopsy case of alpha-fetoprotein-producing large duodenal adenocarcinoma

We report an autopsy case of a large duodenal adenocarcinoma that produced alpha-fetoprotein (AFP). The patient was a man in his 70s with diabetes mellitus. He presented with epigastralgia and was referred to our hospital. Upper gastrointestinal endoscopy and abdominal computed tomography revealed a large tumor of 11 cm in diameter in the descending limb of the duodenum. A tumor biopsy showed poorly differentiated adenocarcinoma. Although his carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) levels were within the normal range, his AFP levels were significantly elevated (42,078.4 ng/mL). Due to vascular invasion, curative resection was not feasible, and chemotherapy was chosen as the treatment option. After gastrojejunostomy was performed to enable oral intake, one cycle of modified leucovorin/5-fluorouracil/oxaliplatin (mFOLFOX6) therapy was administered. However, it proved ineffective, and the patient's anorexia gradually worsened. Ultimately, he succumbed to the progression of cancer cachexia. Autopsy findings revealed a 14-cm-long duodenal carcinoma primarily located in the duodenal bulb, with direct invasion into the stomach, pancreas, and liver. A pathological examination confirmed a diagnosis of poorly differentiated adenocarcinoma with AFP production. Duodenal cancer is rare, and AFP-producing duodenal cancer is even rarer, with only 21 reported cases, including our own. We present this autopsy case of AFP-producing duodenal adenocarcinoma and review the cases reported in the relevant literature.

Effective and Secure Closure after Duodenal Endoscopic Submucosal Dissection: Combination of Endoscopic Ligation with O-Ring Closure and Over-the-Scope Clip

Duodenal endoscopic submucosal dissection (ESD) is associated with high incidences of intraoperative complications and delayed adverse events (AEs). Delayed AEs can be reduced by closing the post-ESD defects. We developed a new method of closure after duodenal ESD, combining endoscopic ligation with O-ring closure (E-LOC) with an over-the-scope clip (OTSC) (Band OTSC; B-OTSC). Here, we conducted a single-center, retrospective, observational study to investigate the efficacy and safety of the B-OTSC method for preventing delayed AEs in patients undergoing duodenal ESD. The study included nine patients with superficial nonpapillary duodenal epithelial tumors who underwent ESD and were closed with B-OTSC from February 2021 to February 2023. There were no delayed AEs (0%), the mean (± standard deviation) closure time was 53 ± 21.6 min, the complete closure rate was 100%, and the mean hospital stay was 7.8 ± 1.8 days. The sustained closure rates at postoperative days 3 and 7 were 88.9% and 88.9%, respectively. The historical analysis indicated a significant difference in cost between B-OTSC and conventional OTSC (p < 0.01). In conclusion, B-OTSC was a safe, secure, and cost-effective method of closure after duodenal ESD, even in patients with post-ESD defects of more than half the circumference.

Mortality in small bowel cancers and adenomas - A nationwide, population-based matched cohort study

BACKGROUND

Small bowel adenocarcinoma (SBA), neuroendocrine tumors (NET) and gastrointestinal stromal tumors (GIST) are neoplastic lesions of the small bowel while small bowel adenomas are precursors of SBA.

AIM

To examine mortality in patients diagnosed with SBA, small bowel adenomas, NET and GIST.

METHODS

We performed a population-based matched cohort study encompassing all individuals with SBA (n = 2289), adenomas (n = 3700), NET (n = 1884) and GIST (n = 509) in the small bowel diagnosed at any of Sweden's 28 pathology departments between 2000 and 2016 (the "ESPRESSO study"). Each case was matched by sex, age, calendar year and county of residence to up to 5 comparators from the general population. Through Cox regression we estimated hazard ratios (HRs) and 95% confidence intervals (95%CIs) for death and cause-specific death adjusting for education.

RESULTS

During follow-up until December 31, 2017, 1836 (80%) deaths occurred in SBA patients, 1615 (44%) in adenoma, 866 (46%) in NET and 162 (32%) in GIST patients. This corresponded to incidence rates of 295, 74, 80 and 62/1000 person-years respectively and adjusted HRs of 7.60 (95%CI=6.95-8.31), 2.21 (2.07-2.36), 2.74 (2.50-3.01) and 2.33 (1.90-2.87). Adjustment for education had a substantial impact on the HR for death in SBA but not for other neoplasias. The predominant cause of excess death was cancer in all groups.

CONCLUSION

This study confirms earlier findings of increased death rates in patients with SBA and NET in a modern study population. We also demonstrate a more than 2-fold increased risk of death in both GIST and the SBA precursor adenoma.

Survival in Colon, Rectal and Small Intestinal Cancers in the Nordic Countries through a Half Century

Background: Survival studies in intestinal cancers have generally shown favorable development, but few studies have been able to pinpoint the timing of the changes in survival over an extended period. Here, we compared the relative survival rates for colon, rectal and small intestinal cancers from Denmark (DK), Finland (FI), Norway (NO) and Sweden (SE). Design: Relative 1-, 5- and 5/1-year conditional survival data were obtained from the NORDCAN database for the years 1971-2020. Results: The 50-year survival patterns were country-specific. For colon and rectal cancers, the slopes of survival curves bended upwards for DK, were almost linear for NO and bended downwards for FI and SE; 5-year survival was the highest in DK. Survival in small intestinal cancer was initially below colon and rectal cancers but in FI and NO it caught up toward the end of the follow-up. Conclusions: Relative survival in intestinal cancers has developed well in the Nordic countries, and DK is an example of a country which in 20 years was able to achieve excellent survival rates in colon and rectal cancers. In the other countries, the increase in survival curves for colon and rectal cancer has slowed down, which may be a challenge posed by metastatic cancers.

Exceptional response to alectinib for duodenal carcinoma with ALK fusion: A case report and literature review

Patients with advanced duodenal carcinoma usually have a poor prognosis due to limited effective chemotherapy options. The study for genotype-directed therapy in patients with duodenal carcinoma is progressing. However, no clinical data assessing the efficacy of molecularly targeted therapy are presently available. We report the case of a 64-year-old woman who was diagnosed with anaplastic lymphocyte kinase (ALK) fusion-positive advanced duodenal carcinoma. Echinoderm microtubule associated protein like-4 (EML4)-ALK rearrangement was detected by comprehensive genomic profiling after resistance to first-line chemotherapy. The patient received alectinib, an ALK inhibitor, with marked shrinkage in primary tumor and liver metastases. She is currently being treated with alectinib for 6 months or more. This is the first report of the efficacy of alectinib in a patient with duodenal carcinoma harboring ALK fusion. Additionally, this case report suggests that the practical use of next-generation sequencing may expand optimal treatment choices in rare solid tumors, including duodenal carcinoma.

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).

Usefulness of magnifying endoscopy with acetic acid and narrow-band imaging for the diagnosis of duodenal neoplasms: proposal of a diagnostic algorithm

BACKGROUND

This study aimed to clarify the features of superficial non-ampullary duodenal epithelial tumors (SNADETs) on magnifying endoscopy with narrow-band imaging (M-NBI) and magnifying endoscopy with acetic acid and narrow-band imaging (M-AANBI), and evaluate the efficacy of M-NBI/M-AANBI to distinguish high-grade adenomas or adenocarcinomas (HGA/AC) from low-grade adenomas (LGA).

METHODS

Clinicopathological data on 62 SNADETs in 58 patients who underwent preoperative M-NBI/M-AANBI and endoscopic resection were retrospectively reviewed. The pathological results were classified into two categories, LGA and HGA/AC. We evaluated microvascular patterns (MVPs) and microsurface patterns (MSPs) observed by M-NBI and MSPs observed by M-AANBI for characterizing LGA and HGA/AC. The kappa value was calculated to assess the interobserver and intraobserver agreements of evaluation of M-AANBI images.

RESULTS

Pathologically, 38 lesions (61.3%) were LGA and 24 lesions (38.7%) were HGA/AC. HGA/AC tended to have irregular MVP and/or MSP on M-NBI. M-NBI diagnostic performance to distinguish HGA/AC from LGA showed 62.5% sensitivity, 68.4% specificity, and 66.1% accuracy. SNADETs had irregular MSP on M-AANBI. Three irregularity grades (iG) of MSP were observed by M-AANBI as follows: iG1, mild; iG2, moderate; iG3, significant. HGA/AC lesions had a significantly higher rate of iG3 than LGA lesions (p < 0.001). The iG2 was associated with HGA/AC in elevated lesions and LGA in depressed lesions. The diagnostic performance of M-AANBI was as follows: 95.8% sensitivity, 97.4% specificity, and 96.8% accuracy. The diagnostic accuracy of M-AANBI was significantly higher than that of M-NBI (p < 0.001). The kappa value for interobserver agreement on the diagnosis and irregularity grading of M-AANBI images was 0.742 and 0.719, respectively. These data indicate substantial interobserver agreement. Based on the above-mentioned results, we developed a M-AANBI diagnostic algorithm for SNADETs.

CONCLUSION

The diagnostic algorithm for SNADETs using M-AANBI may be useful for differentiating between LGA and HGA/AC.

Comparison of Endoscopic Ultrasonography and Conventional Endoscopy for Prediction of Tumor Depth in Superficial Nonampullary Duodenal Epithelial Tumors

BACKGROUND

The utility of endoscopic ultrasonography (EUS) in predicting tumor depth among superficial nonampullary duodenal epithelial tumors (SNADETs) is unclear. The aim was to compare EUS with conventional endoscopy (CE) for the evaluation of tumor invasion of SNADETs.

METHODS

A retrospective analysis was performed on consecutive 174 lesions/169 patients with duodenal dysplasia or adenocarcinoma with invasion up to submucosa who underwent both CE and EUS before endoscopic (n = 133) or surgical (n = 41) treatment. Endoscopic staging by CE was performed based on the characteristic endoscopic criteria of submucosal invasion (irregular surface, submucosal tumor [SMT]-like marginal elevation, and fusion of converging folds). The diagnostic performance of each test was compared with the final histology.

RESULTS

The sensitivity and accuracy of estimating the depth were higher for CE compared to that of EUS (99.4% vs. 89.4%, p < 0.01 and 97.7% vs. 87.9%, p < 0.01, respectively). Univariate analysis of endoscopic factors revealed that tumor diameter, red color, SMT-like appearance, and hypoechogenicity were factors related to advanced histology. Multivariate analysis revealed that the presence of SMT-like appearance based on CE was an independent factor to predict submucosal invasion (p = 0.025). Gross morphology of the combined type was associated to incorrect diagnosis of EUS (p = 0.007). Among 3 cases in which EUS overestimated the tumor depth, carcinoma extension in submucosal Brunner's gland or nontumorous submucosal cystic dilation was observed.

CONCLUSION

EUS may not be necessary, and CE may be sufficient for determining the optimal therapeutic strategy for SNADETs.

Systemic Therapy for Microsatellite Instability Small Bowel Adenocarcinoma With Mesenteric Vascular Embolism as Initial Symptom: A Case Report

Background: Small bowel adenocarcinoma are relatively rare tumors of the digestive system. Due to the lack of specific screening methods, patients are often diagnosed at an advanced stage. At present, there is no specific surgical guidance and chemotherapy regimen for small bowel adenocarcinoma. Here, we report a rare small bowel adenocarcinoma case with mesenteric vascular embolization and microsatellite instability, in which palliative surgery combined with chemotherapy and anti-Programmed cell death protein 1(PD-1) therapy resulted in complete remission.

Case Presentation: The patient was a 55-year-old man who was admitted for suspected small bowel adenocarcinoma combined with incomplete ileus, mesenteric vascular occlusion and distant metastasis. We performed palliative surgery to remove adenocarcinoma as well as relieve obstruction. Then according to the pathological and immunohistochemical results (Stage IV and microsatellite instability), we used XELOX regimen combined with anti-PD-1 therapy. In last 2 years follow up, this patient achieved complete remission.

Conclusions: The possibility of small intestinal tumor should be considered in patients with mesenteric vascular obstruction. PD-1 blockade is an effective therapy for small bowel adenocarcinoma with microsatellite instability.

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.

Risk Factors for Non-Ampullary Duodenal Adenocarcinoma: A Systematic Review

INTRODUCTION

An increase in the incidence of duodenal adenocarcinoma has been recently reported. However, little is known about the risk factors for duodenal adenocarcinoma, which are important for screening purposes. We, therefore, aimed to conduct a systematic review to identify risk factors for non-ampullary duodenal adenocarcinoma.

METHODS

A medical literature search was performed using electronic databases, including PubMed, Cochrane Library, Japan Medical Abstracts Society, and Web of Science. Studies that assessed the association between dietary habits, lifestyle behaviors, comorbidities, and non-ampullary duodenal adenocarcinoma were extracted. The Newcastle-Ottawa Scale was used to assess the risk of bias in individual studies, and the Grading of Recommendations, Assessment, Development, and Evaluations approach was used to assess the quality of evidence across studies included in this review.

RESULTS

Out of 1,244 screened articles, 10 were finally selected for qualitative synthesis. In the general population, no consistent risk factors were identified except for Helicobacter pylori positivity, which was considered a risk factor in 2 studies, but the quality of evidence was considered very low because of the high risk of bias. In patients with familial adenomatous polyposis (FAP), Spigelman stage IV at initial endoscopy was considered a consistent risk factor in 3 studies.

CONCLUSIONS

There are currently limited data regarding risk factors for non-ampullary duodenal adenocarcinoma, and no conclusive risk factors were identified in the general population. However, in patients with FAP, Spigelman stage IV was identified as a consistent risk factor. Further studies are needed to improve diagnosis and support effective clinical management of this malignancy.

Time trends in incidence and survival of small intestinal cancer in Sweden

BACKGROUND

Small intestinal cancer is less common than some other gastrointestinal malignancies. Tumours of different histological types and anatomical sites of origin have therefore often been described together. The aim of this study was to investigate the epidemiology for each of the four main subtypes: duodenal adenocarcinoma (D-AC), duodenal neuroendocrine tumour (D-NET), jejunoileal adenocarcinoma (J/I-AC), and jejunoileal neuroendocrine tumour (J/I-NET).

METHODS

All patients with small intestinal cancer diagnosed between 1960 and 2015 were identified from the Swedish Cancer Register. The age-adjusted incidence rate with incidence rate ratios, as well as overall (OS) and net (NS) survival, were determined and temporal trends were analysed.

RESULTS

The incidence rate was highest for J/I-NET, with 9.98 clinical diagnoses per million in 2010-2015. Clinical diagnosis of D-AC increased more than 10-fold and surpassed J/I-AC as the second most common subtype. D-NET was by far the least common subtype. Diagnosis at autopsy became less common over time, whereas clinical diagnoses increased significantly for all four subtypes. All subtypes except J/I-AC affected men more often than women. The age distribution was similar between subtypes, although patients with adenocarcinomas were slightly older. Survival was generally much better for patients with NET than for those with adenocarcinoma. Both OS and NS showed a negative association with advancing age. Survival improved only for J/I-NET from a 5-year NS of 0.69 in the 1960s to 0.81 in 2010-2015.

CONCLUSION

The incidence of small intestinal cancer is increasing, particularly for D-AC and in the elderly. Survival of patients with small intestinal cancer has improved only for J/I-NET over the last decades.

Comparative Analysis of Outcomes and Clinicopathological Characteristics of Duodenal Adenocarcinoma: A SEER Analysis

Duodenal adenocarcinoma is an uncommon, malignant tumor usually accompanied by a poor prognosis. We identified 3150 duodenal adenocarcinoma cases from the SEER database (1988-2013) to analyze clinical characteristics and outcomes. The Kaplan-Meier method was used to evaluate cancer-specific survival (CSS). Cox regression analysis was used to explore the prognostic factors of CSS. Adverse prognostic factors include higher tumor grade, later stage, tumor size ≥ 2cm, positive regional lymph nodes, and not undergoing surgical resection. Our results suggest, surgery is the optimal treatment for duodenal cancer, and combined radiotherapy does not improve survival.

Small bowel tumours: update in diagnosis and management

PURPOSE OF REVIEW

The aim of this study was to summarize the role of recently developed diagnostic techniques in the diagnosis and management of patients with small bowel tumours (SBTs).

RECENT FINDINGS

Recent studies show that the overall SBT incidence is increasing. The introduction of small bowel dedicated diagnostic tools [i.e. capsule endoscopy, device-assisted enteroscopy (DAE), computed tomography (CT) and MRI-enterography] might partially explain this trend. In patients with SBT, DAE might represent an ideal tool by coupling careful mucosal inspection with sampling capability. Unfortunately, DAE is an invasive procedure and seldom allows complete small bowel evaluation in a single setting. Therefore, DAE is more often used in clinical practice as confirmatory tool, when other less invasive and readily available tests (i.e. capsule endoscopy or radiological tests) identify relevant findings. Nevertheless, in patients with SBT, capsule endoscopy is burdened by an increased risk of capsule retention and/or missing proximal small bowel lesions, whereas dedicated cross-sectional imaging techniques often identify nonspecific findings of limited clinical significance.

SUMMARY

Despite recent technical improvements, in patients with SBT, the result of a single diagnostic procedure is often insufficient to provide a definite diagnosis. A balanced combination of different tests allows reaching a final diagnosis and drive further management.

The Natural History of IBD: Lessons Learned

PURPOSE OF REVIEW

Inflammatory bowel diseases (IBD), which include Crohn's disease (CD) and ulcerative colitis (UC), are chronic, relapsing diseases with unknown etiologies. The purpose of this review is to present the natural disease course evidenced in the latest epidemiology data.

RECENT FINDINGS

The prevalence of IBD is rapidly increasing, affecting five million patients worldwide with the highest incidence observed in Northern Europe and Northern America. It has been shown that both CD and UC patients are at an increased risk for developing cancer of the gastrointestinal tract compared to the general population. Though the disease course of IBD is unpredictable, the rate of surgical treatment has declined potentially as a consequence of the introduction of immunomodulators and new biologic treatment options. Treatments with biological agents and/or immunosuppressive drugs as well as disease monitoring with eHealth devices seem to have a positive impact on the disease course. However, long-term follow-up studies are still lacking and therefore no reliable conclusions can be drawn as of yet. Medical compliance is paramount in the treatment of IBD, and continuous research focusing on approaches that increase compliance is also necessary.

Inflammatory Bowel Disease and Small Bowel Cancer Risk, Clinical Characteristics, and Histopathology: A Population-Based Study

BACKGROUND & AIMS

Inflammatory bowel disease (IBD) may increase risk of small bowel cancer (SBC). However, little is known of the characteristics and features of IBD-SBC, due to a low number of cases worldwide. We performed a population-based study of IBD and SBC to calculate risk and increase our understanding of clinical characteristics and histopathological and molecular features.

METHODS

The study population consisted of all individuals aged 16 years or older living in Denmark during 1978-2010. Through linkage between national registers and subsequent scrutiny of medical records and pathology descriptions, we identified 40 cases of IBD-SBC. Risk was calculated by standardized incidence ratio (SIR) (observed/expected); patient characteristics were derived from medical files, and surgery specimens were obtained from hospitals nationwide for histopathological and molecular analyses.

RESULTS

During 241,620 person-years of follow-up, 23 patients with Crohn's disease developed small bowel adenocarcinoma (SIR, 14.38; 95% confidence interval, 8.78-22.20) and 9 developed neuroendocrine tumors (SIR, 6.83; 95% confidence interval, 3.13-12.97). No significantly increased risk of SBC was found among patients with ulcerative colitis. Most patients with SBC had moderate-to-severe Crohn's disease with small bowel and upper gastrointestinal involvement. Assessment of surgical specimens of small bowel adenocarcinomas revealed a clear transition from inflammation to dysplasia and cancer, whereas no tumors had evidence of microsatellite instability.

CONCLUSIONS

In a population-based study of patients in Denmark with IBD and SBC, we found risk of adenocarcinomas and neuroendocrine tumors to be increased among persons with Crohn's disease. Most patients with IBD-SBC had extensive IBD of moderate-to-severe activity. Adenocarcinomas appeared to develop via an inflammation-dysplasia-carcinoma pathway, but differed from IBD-related colorectal adenocarcinomas in their molecular features.

Neoplastic Diseases of the Small Bowel

The incidence of small bowel tumors is increasing over time. Until recently, their diagnosis was delayed and it was often reached only at the time of surgery. New diagnostic tools, such as capsule endoscopy, device-assisted enteroscopy, and dedicated small bowel cross-sectional imaging techniques, have been introduced recently in clinical practice. The combination of these tools allows medical practitioners to detect small bowel tumors at an early stage and to reach a definite diagnosis before surgery, thus enabling minimally invasive treatments.