Impact of Crohn's Disease on the Survival of Patients with Small-Bowel Adenocarcinoma in Korea: A Bicenter Cohort Study.

Background/Aims: Owing to the low prevalence of small-bowel adenocarcinoma (SBA), data on the impact of Crohn's disease (CD) on the survival of patients with SBA are lacking. Therefore, we investigated this issue in this study. Methods: In this bicenter cohort study, patients with histologically confirmed SBA were retrospectively enrolled and classified into two groups: sporadic SBA and CD-associated SBA. Patients with duodenal SBA were excluded. Overall survival, disease-free survival, and factors associated with survival were analyzed. Results: Of 128 patients with SBA, 115 had sporadic SBA and 13 had CD-associated SBA. Ileal involvement and poorly differentiated tumors were more common in the CD-associated SBA group than in the sporadic SBA group (ileal involvement, 53.8% vs 22.6%; poor differentiation, 46.2% vs 14.8%; both p<0.05). In survival analysis, overall survival showed no statistical difference between the sporadic SBA and CD-associated SBA groups (p=0.370). However, when stratified by stage, the adjusted overall survival of the CD-associated SBA group was lower in patients with an advanced disease stage (p=0.029). Disease-free survival showed the same tendency, albeit without clinical significance (p=0.097). CD (hazard ratio [HR], 2.308; p=0.047), older age (≥65 yr) at SBA diagnosis (HR, 2.766; p=0.001), and stage III/IV disease (HR, 3.151; p<0.001) were factors associated with mortality. Conclusions: The overall survival of patients with CD-associated SBA did not differ from that of patients with sporadic SBA. However, as CD is an independent risk factor for mortality, vigilant surveillance in high-risk patients may be crucial.

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.

Neuroendocrine Tumors of Meckel's Diverticula: Rare but Fare Well.

Neuroendocrine tumors (NETs) are the most common malignancy arising in Meckel's diverticula (MDs). To date, there are no large series characterizing these tumors. The National Cancer Database was queried for patients with MD NETs (n = 162) from 2004 to 2014. Patient and tumor characteristics as well as outcomes were analyzed. MD NETs were more common in men (72.8%) at a median age of 62 years; 95.1 per cent of patients were white. All patients underwent surgery. Clinical M0 disease was present in 97.4 per cent of patients, and 88.2 per cent of tumors were well differentiated. Lymphovascular invasion was present in 13.2 per cent. Most (60.4%) tumors were less than 10 mm. Lymphadenectomy was performed in 32.9 per cent of patients, with 52.1 per cent of these found to have metastatic lymph node disease. Although most MD NETs are well differentiated, smaller than 10 mm, and do not have lymphovascular invasion, lymph node metastases are commonly found, suggesting that mesenteric lymphadenectomy with adequate resection of the small bowel may be necessary for adequate staging and disease clearance.

Ileocolonic neuroendocrine tumours identified in the English bowel cancer screening programme.

AIM: Ileocolonic neuroendocrine tumours (NETs) are diagnosed as part of bowel cancer screening programmes (BCSPs). The aim of this study was to identify and characterize NETs diagnosed within the English BCSP, a double-screen programme that uses guaic faecal occult blood test (gFOBT) screening and colonoscopy, by interrogating the national colorectal screening database and validating the findings with individual BCSP centres. METHOD: The Exeter database was interrogated by running queries to identify participants with coded NETs (from the start of the programme in July 2006 - 1 December 2014). A written proforma was sent to the responsible BCSP clinician for validation and characterization. RESULTS: During this period, 13 061 716 participants were adequately screened using gFOBTs, and 259 765 participants had definitively abnormal results. There were 146 unique participants with NET-related codes from 216 707 BCSP colonoscopies. The diagnosis rates per 100 000 colonoscopies were 29 rectal, 18 colonic and 11 ileal NETs. The majority of rectal NETs had Grade 1 (80%) and Stage T1 (85.1%) disease. Over half of ileal NETs (53.6%) in this study had invasive disease, with 85.2% having nodal and 36.1% having metastastatic disease. CONCLUSION: The current study highlights the rate of colorectal NETs diagnosed in the English BCSP. These data highlight a higher-than-anticipated incidence, and the potential additional benefit of BCSPs in identifying occult NETs.

Duodenal localization is a negative predictor of survival after small bowel adenocarcinoma resection: A population-based, propensity score-matched analysis.

BACKGROUND AND OBJECTIVES: This study assessed the influence of tumor localization of small bowel adenocarcinoma on survival after surgical resection. METHODS: Patients with resected small bowel adenocarcinoma, ACJJ stage I-III, were identified from the Surveillance, Epidemiology, and End Results database from 2004 to 2013. The impact of tumor localization on overall and cancer-specific survival was assessed using Cox proportional hazard regression models with and without risk-adjustment and propensity score methods. RESULTS: Adenocarcinoma was localized to the duodenum in 549 of 1025 patients (53.6%). There was no time trend for duodenal localization (P = 0.514). The 5-year cancer-specific survival rate was 48.2% (95%CI: 43.3-53.7%) for patients with duodenal carcinoma and 66.6% (95%CI: 61.6-72.1%) for patients with cancer located in the jejunum or ileum. Duodenal localization was associated with worse overall and cancer-specific survival in univariable (HR = 1.73; HR = 1.81, respectively; both P < 0.001), multivariable (HR = 1.52; HR = 1.65; both P < 0.001), and propensity score-adjusted analyses (HR = 1.33, P = 0.012; HR = 1.50, P = 0.002). Furthermore, young age, retrieval of more than 12 regional lymph nodes, less advanced stage, and married matrimonial status were positive, independent prognostic factors. CONCLUSIONS: Duodenal localization is an independent risk factor for poor survival after resection of adenocarcinoma.

Association between neuroendocrine tumor of the ileum and two colonic primary malignancies. A case report and review of literature.

BACKGROUND: A high rate of association between neuroendocrine tumors (NETs) and secondary primary malignancy (SPM) has been described in literature and this association can occur either in a synchronous or a metachronous presentation. A wide range of hypothesis has been postulated to explain the high rate of association between NETs and SPM, without definitive conclusions. CASE PRESENTATION: We report a case of an ileal neuroendocrine tumor found incidentally at the histologic examination of the surgical specimen in a 72 years old male underwent to right hemi colectomy for two colic adenomatous polips with high grade dysplasia. CONCLUSION: Large multicentric epidemiological studies should be considered to assess the association between NETs and SPM. KEY WORDS: Neuroendocrine tumors (NETs), Progression-Free Survival (PFS), Secondary primary malignancy (SPM).

Trends in incidence, treatment and survival of small bowel adenocarcinomas between 1999 and 2013: a population-based study in The Netherlands.

BACKGROUND: We conducted a population-based study to establish the incidence, treatment and overall survival over time of patients with small bowel adenocarcinoma. MATERIAL AND METHODS: All patients diagnosed with small bowel adenocarcinoma in the Netherlands between 1999 and 2013 were included (n = 1775). Age-standardized incidence rates were calculated per 100 000 person-years using the European standardized population rate. The influence of patient and tumor characteristics on the administration of chemotherapy was analyzed by means of a multivariable logistic regression analysis. The Cochran-Armitage trend test was conducted to evaluate trends in treatment and survival and the Cox proportional hazards model was used to identify prognostic factors of overall survival. RESULTS: The incidence of small bowel adenocarcinomas increased, mainly due to an almost twofold increase of duodenal adenocarcinomas. Patients with locoregional duodenal tumors were less likely to undergo surgery (58%), towards 95% of the locoregional jejunal and ileal tumors (p < 0.0001). The use of chemotherapy doubled for adjuvant (7-15%) and palliative chemotherapy (19-37%). Median overall survival of patients with locoregional disease increased from 19 to 34 months (p = 0.0006), whereas median overall survival of patients with metastatic disease remained 4-5 months. Favorable prognostic factors for prolonged survival in locoregional disease, identified by multivariable survival analysis, included age <60 years, tumor stage I or II, diagnosis in 2009-2013, surgical treatment and chemotherapy. Favorable prognostic factors for prolonged survival in metastatic disease were age <50 years, jejunal tumors, surgical treatment and chemotherapy. CONCLUSION: Small bowel adenocarcinomas are rare tumors with an increasing incidence. The administration of adjuvant and palliative chemotherapy doubled, but median overall survival only increased for patients with locoregional disease. Given the rarity and dismal prognosis, it is important to develop international studies to determine the optimal treatment for these patients.

Increased risk of colorectal neoplasia in adult patients with cystic fibrosis: a matched case-control study.

OBJECTIVE: As the lifespan of patients with cystic fibrosis (CF) increases, concerns regarding the occurrence of bowel cancer have arisen. However, previous cohort studies have yielded contradictory results as to the risk of colorectal cancer (CRC) in the CF population. The aim of this study was to determine whether CF is associated with an increased risk of colorectal neoplasia. METHODS: We performed a matched case-control study at a statewide CF center. Cases were adult CF patients undergoing colonoscopy in a 5-year period from 2007 to 2012. Controls were matched in a 2:1 ratio for age, gender, and colonoscopy indication. RESULTS: A total of 50 patients with CF who underwent colonoscopy were identified. Among CF patients, there were 5 (10%) cases with CRC, 1 (2%) with ileal adenocarcinoma, 13 (26%) with adenomas, and 16(32%) with advanced adenomas. In contrast, there was 1 (1%) case with CRC, 11 (11%) with adenomas, and 6 (6%) with advanced adenomas identified among controls. Compared to controls, CF was associated with a 10-fold increased risk of CRC (odds ratio [OR] = 10.0, 95% confidence interval [CI]: 1.2-85.6; p = 0.03), threefold increased risk of adenomas (OR = 3.34, 95%CI: 1.23-9.08; p = 0.018], and sevenfold increased risk of advanced adenomas (OR = 6.95, 95% CI: 2.30-21.01; p = 0.001). Moreover, the quality of bowel preparation was significantly worse in CF patients with a fourfold (p = 0.01) increased likelihood of a poor preparation. CONCLUSIONS: Our data suggest that CF patients are at significantly increased risk of CRC compared to age, sex, and colonoscopy-indication matched controls. Consideration should be given to the introduction of a CRC surveillance program in the CF population.

Neoplasia in the ileoanal pouch following colectomy in patients with ulcerative colitis and primary sclerosing cholangitis.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC) is typically associated with inflammatory bowel disease (IBD), particularly ulcerative colitis (UC). PSC-IBD patients are at an increased risk for colorectal neoplasia. The ileal pouch-anal anastomosis (IPAA) is a treatment option for patients with medically refractory UC or neoplasia. However, little is known about the development of pouch neoplasia in PSC-UC patients following an IPAA. We aim to describe the incidence of pouch neoplasia in PSC-UC patients after an IPAA. METHODS: We conducted a retrospective chart review of patients with a confirmed diagnosis of PSC and IBD who underwent colectomy with IPAA followed by pouch surveillance between 1995 and 2012. RESULTS: Sixty-five patients were included in the cohort and were followed up from the time of colectomy/IPAA for a median of 6years. The most common indications for surgery were low-grade dysplasia (LGD) and refractory colitis. Only 3 patients developed evidence of neoplasia (LGD n=1, high-grade dysplasia n=1, adenocarcinoma n=1). The cumulative 5-year incidence of pouch neoplasia was 5.6% (95% confidence intervals [CI], 1.8%-16.1%). CONCLUSION: Based on our short-term follow-up, surveying the pouch frequently appears to be an unnecessary practice in PSC-IBD patients. Longer follow-up will be needed to develop an optimal surveillance strategy for the development of dysplasia and cancer in such patients.

Non-colorectal intestinal tract carcinomas in inflammatory bowel disease: results of the 3rd ECCO Pathogenesis Scientific Workshop (II).

Patients with inflammatory bowel diseases (IBD) have an excess risk of certain gastrointestinal cancers. Much work has focused on colon cancer in IBD patients, but comparatively less is known about other more rare cancers. The European Crohn's and Colitis Organization established a pathogenesis workshop to review what is known about these cancers and formulate proposals for future studies to address the most important knowledge gaps. This article reviews the current state of knowledge about small bowel adenocarcinoma, ileo-anal pouch and rectal cuff cancer, and anal/perianal fistula cancers in IBD patients.

Small bowel adenocarcinoma: epidemiology, risk factors, diagnosis and treatment.

Small bowel adenocarcinomas are rare tumours, but their incidence is increasing. Their most common primary location is the duodenum. The few studies that have collected data regarding small bowel adenocarcinoma are not homogeneous and are widely spread over time. Even though these tumours are most often sporadic, some predisposing diseases have been identified, among which Crohn's disease and genetic syndromes. Early diagnosis of small bowel adenocarcinoma remains difficult despite significant radiological and endoscopic progress. After surgical resection the main prognostic factor is node invasion; in this case, adjuvant chemotherapy can be expected to be beneficial, although this has not been established by randomised trials. For metastatic disease, platinum-based chemotherapy seems to be the most effective treatment. Targeted therapies have not yet been evaluated in this type of cancer.

Risk of ileal pouch neoplasms in patients with familial adenomatous polyposis.

Restorative proctocolectomy is the most common surgical option for patients with familial adenomatous polyposis (FAP). However, adenomas may develop in the ileal pouch mucosa over time, and even carcinoma in the pouch has been reported. We therefore reviewed the prevalence, nature, and treatment of adenomas and carcinoma that develop after proctocolectomy in the ileal pouch mucosa in patients with FAP. In 25 reports that were reviewed, the incidence of adenomas in the ileal pouch varied from 6.7% to 73.9%. Several potential factors that favor the development of pouch polyposis have been investigated, but many remain controversial. Nevertheless, it seems certain that the age of the pouch is important. The risk appears to be 7% to 16% after 5 years, 35% to 42% after 10 years, and 75% after 15 years. On the other hand, only 21 cases of ileal pouch carcinoma have been recorded in the literature to date. The diagnosis of pouch carcinoma was made between 3 to 20 years (median, 10 years) after pouch construction. Although the risk of malignant transformation in ileal pouches is probably low, it is not negligible, and the long-term risk cannot presently be well quantified. Regular endoscopic surveillance, especially using chromoendoscopy, is recommended.

Small intestinal cancers among adults in an Egyptian district: a clinicopathological study using a population-based cancer registry.

BACKGROUND: Small intestinal cancers (SICs) are very rare all over the world and little is known about them in Egypt. METHODS: This a retrospective study. Between 2000 and 2002, 30 cases with SICs were identified in the Gharbiah population based cancer registry (GPBCR); 17 cases of whom were treated at Tanta Cancer Center (TCC). RESULTS: The median age was 51 years with female predominance. The duodenum was the commonest site (43%) followed by the ileum then the jejunum. Adenocarcinoma (AC), carcinoids, gastrointestinal stromal tumors (GISTs), lymphoma and sarcoma represented 50%, 10%, 17%, 13% and 10% respectively. Abdominal pain was the commonest symptom and localized disease was the commonest presentation. Surgery, chemotherapy and radiotherapy were employed in 65%, 35% and 0% of patients, respectively. The median overall survival and progression free survival (OS, PFS) were 18 and 15 months (95% CI: 10.4-25.6 and 3.6-26.4), respectively. AC had inferior OS and PFS to other histologies (p = 0.08 and 0.12, respectively). Also, duodenum subsite was inferior in OS and PFS to other sites (p = 0.25 and 0.35, respectively). CONCLUSIONS: SICs in Gharbiah, Egypt are characterized by predominance of female gender and adenocarcinoma histology. One year survival is 64% with a poor outcome for adenocarcinoma and duodenal subsite.

Prevalence and risk factors for adenomas in the ileal pouch and the afferent loop after restorative proctocolectomy for patients with familial adenomatous polyposis.

BACKGROUND: Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) has become the treatment of choice in familial adenomatous polyposis (FAP) to prevent the risk of colorectal cancer. However, it currently is recognized that adenomas may develop in the ileal pouch. The risk of adenoma occurring in the afferent ileal loop above the pouch is less clearly identified. This study aimed to evaluate the difference in prevalence of adenomas between the ileal pouch and the afferent ileum after IPAA in FAP. METHODS: The study analyzed 442 endoscopies performed between 2003 and 2008 for 139 FAP patients. The patients had undergone an IPAA in 118 cases, an ileorectal anastomosis in 13 cases, or an ileostomy in 8 cases. RESULTS: Among the 118 IPAA patients, 57 (48.3 %) had pouch adenomas a median of 15 years after surgery. The risk factors for pouch adenomas were delay since pouch construction [odds ratio (OR), 1.11; p = 0.016] and presence of advanced duodenal adenomas (OR, 4.35; p = 0.011). Seven patients had pouch adenomas with high-grade dysplasia. Only nine patients had afferent ileal loop adenomas (6.5 %). The only significant risk factor for ileal adenomas was the presence of pouch adenomas (OR, 2.16; p = 0.007). CONCLUSION: After restorative proctocolectomy in FAP, adenoma recurrence is frequent in the pouch, with a higher risk for patients with advanced duodenal adenomas and an increasing risk over time, whereas adenomas are rarely found in the afferent ileal loop. This finding may help to propose redo ileal pouch anal anastomosis if required.

Incidence, presentation, and prognosis of small bowel adenocarcinoma in patients with small bowel Crohn's disease: a prospective observational study.

BACKGROUND: Patients with Crohn's disease (CD) of the colon are at risk for colorectal cancer and should be screened for dysplasia and cancer of the colon. Small bowel adenocarcinoma (SBA) is a complication of small bowel CD and carries a poor prognosis. However, there is no screening test for SBA in patients with small bowel CD. The aim of this study was to assess the risk and incidence of SBA in a large prospective cohort of patients with small bowel CD and to compare it with the risk of colorectal cancer in patients with CD involving the colon, recruited in the same cohort. METHODS: In a nationwide French cohort, 11,759 patients with CD were enrolled by 680 gastroenterologists. The SBA risk was obtained by dividing the observed cases in our cohort to the expected cases in the general population. RESULTS: At baseline, 8222 (69.9%) patients had small bowel CD (either alone or associated with colonic CD); their median follow-up was 35 months (interquartile range, 29-40). Five new cases of SBA were diagnosed, all in patients with small bowel CD, within inflamed areas. Among the 5 patients with incident SBA, 4 died of SBA and 1 is in remission 7 years after the diagnosis of SBA. The incidence rates of SBA were 0.235 per 1000 patient-years (95% confidence interval [CI], 0.076-0.547) among patients with small bowel CD and 0.464 per 1000 patient-years (95% CI, 0.127-1.190) among those with small bowel CD for >8 years. This accounted for approximately 30% of the risk of colorectal cancer in patients with CD of the colon. Patients with small bowel CD and small bowel CD for >8 years had an SBA standardized incidence ratio of 34.9 (95% CI, 11.3-81.5) and 46.0 (95% CI, 12.5-117.8), respectively. CONCLUSIONS: SBA in patients with small bowel CD carries a poor prognosis, and its risk is approximately 30% of colorectal cancer risk in patients with CD of the colon. Further studies should determine if small bowel endoscopic screening in high-risk patients is feasible and effective.

Laparoscopic sleeve gastrectomy as a step approach for morbidly obese patients with early stage malignancies requiring rapid weight loss for a final curative procedure.

BACKGROUND: Laparoscopic sleeve gastrectomy is a relatively new treatment modality implemented in the surgical management for morbid obesity. It has been well documented that obesity is not only associated with an increased risk of malignancies but is also consistent with a higher incidence of surgical complications related to its definitive management. In spite of the weight loss experienced by patients with malignancy due to a catabolic state, bariatric surgery might be considered as a step procedure allowing for a more efficient and suitable surgical approach to treat early stage malignancies, thereby decreasing the procedure-related morbidity and mortality. This study aims to examine the effectiveness of laparoscopic sleeve gastrectomy as a primary weight loss procedure in patients with untreated malignancy facilitating a definitive oncologic surgical approach. METHODS: After institutional review board approval and following Health Insurance Portability and Accountability Act guidelines, we conducted a retrospective review of a prospectively collected database. From September 2006 to March 2009, we analyzed all morbidly obese patients with early stage malignancy that underwent laparoscopic sleeve gastrectomy at the Bariatric and Metabolic Institute as a weight loss surgery prior to a second oncologic procedure. The variables examined were excess body weight, percent excess weight loss, comorbidities, malignancy type, preoperative body mass index (BMI), postoperative BMI, morbidity, and mortality. Mean follow-up time was 3 months until an oncologic procedure was performed. RESULTS: Our series included four morbidly obese patients. There were three males and one female, with a mean age of 53.75 years (range 27-67 years) and a mean BMI of 48.25 kg/m(2) (range 42-55 kg/m(2)). Mean excess weight in our patient population 176 lbs. Mean weight loss at 3 months after laparoscopic sleeve gastrectomy was 59.35 lbs (range 28-79 lbs). Comorbidities included diabetes mellitus, hypertension, obstructive sleep apnea, chronic obstructive pulmonary disease, Crohn's disease, coronary artery disease, and previous history of DVT. One patient was diagnosed with a small bowel carcinoid, two patients with renal hypernephroma, and one patient with prostate cancer. After an average time of 3 months, patients underwent a definitive procedure in accordance to their type of malignancy. There were neither postoperative complications nor mortality. CONCLUSIONS: Laparoscopic sleeve gastrectomy is a safe and reasonable approach to effectively reduce weight in order to allow morbidly obese patients with early stage malignancies to undergo a second oncologic procedure.

Adenoma formation and malignancy after restorative proctocolectomy with or without mucosectomy in patients with familial adenomatous polyposis.

BACKGROUND: There is controversy concerning whether or not to perform mucosectomy after IPAA in patients with familial adenomatous polyposis. Although more frequent adenoma formation at the anastomotic site in patients without a mucosectomy is documented, the interpretation of the theoretical reflections and empirical findings are ambiguous. OBJECTIVE: The aim of this study was to assess the differences in adenoma formation at the anastomotic site and in the ileal pouch among patients with familial adenomatous polyposis after IPAA with or without mucosectomy. DESIGN: Data were gathered from The Norwegian Polyposis Registry and The Cancer Registry of Norway. PATIENTS: Sixty-one patients with familial adenomatous polyposis who had IPAA were included in the Norwegian Polyposis Registry. MAIN OUTCOME MEASURES: The frequency of adenoma development in the pouch or at the anastomotic site was measured. RESULTS: Thirty-nine patients had a pelvic pouch performed with mucosectomy and 22 patients without. The observational time was 15.5 and 13.7 years. Adenoma formation at the anastomotic site was 4 in 39 and 14 in 22, and the estimated rate was 17% vs 75% (p = 0.0001). One patient without mucosectomy had a cancer (Dukes A) at the anastomotic site. There was no estimated long-term difference in adenoma formation in the ileal pouches between the 2 surgical procedures (38%) (p = 0.10). LIMITATIONS: The study is retrospective, in part, and relies on data from registries. There is a limited number of cases, and selection bias because of surgeon preference may exist. CONCLUSION: In patients with familial adenomatous polyposis who undergo IPAA, adenoma formation at the anastomotic site is significantly reduced after mucosectomy. Mucosectomy may be the preferable procedure to prevent adenomas at the anastomotic site.

Reproductive history and risk of small bowel cancer by histologic type: a population-based study.

PURPOSE: The male predominance of the two main histologic malignancies of the small bowel cancer may reflect a role of sex hormones which will be examined in this study. METHODS: This was a nationwide population-based nested case-control study, based on a cohort of subjects born between 1932 and 2008, as identified in the Swedish Multi-Generation Register. For each case of small bowel cancer, 10 age- and sex-matched controls were randomly selected. Number of children and age at having the first child were analyzed in relation to the risk of small bowel cancer using conditional logistic regression, providing odds ratios (ORs) and 95 % confidence intervals (CIs). RESULTS: A total of 632 female cases and 894 male cases of small bowel cancer were included. No overall increased risk of small bowel cancer was found in parous compared to non-parous women (OR = 1.02, 95 % CI 0.67-1.54). There was no association between age at first birth and small bowel cancer (>30 years of age vs <20 years; OR = 1.04, 95 % CI 0.72-1.50). No associations were detected in separate analyses of adenocarcinoma or carcinoid of the small bowel. No distinct risk patterns were discerned in men compared to women. CONCLUSIONS: Reproductive history does not seem to be associated with the risk of small bowel cancer, independent of histologic type.