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

BACKGROUND: Small intestinal adenocarcinomas (SIAs) are rare. Hence, randomized controlled trials are lacking and understanding of the disease features is limited. This nationwide cohort investigates incidence, treatment and prognosis of SIA patients, to improve disease outcome. PATIENTS AND METHODS: Data of 2697 SIA patients diagnosed from January 1999 through December 2019 were retrieved from the Netherlands Cancer Registry and Pathology Archive. Incidence was calculated using the revised European Standardized Rate. The influence of patient and tumor characteristics on overall survival (OS) was studied using survival analyses. RESULTS: The age-standardized incidence rate almost doubled from 0.58 to 1.06 per 100,000 person-years, exclusively caused by an increase in duodenal adenocarcinomas. OS did not improve over time. Independent factors for a better OS were a younger age, jejunal tumors, Lynch syndrome and systemic therapy. Only 13.8% of resected patients was treated with adjuvant chemotherapy, which improved OS compared to surgery alone in stage III disease (HR 0.47 (0.35-0.61)), but not in the limited group of deficient mismatch repair (MMR) patients (n = 53, HR 0.93 (0.25-3.47)). In the first-line setting, CAPOX was associated with improved OS compared to FOLFOX (HR 0.51 (0.36-0.72)). For oligometastatic patients, a metastasectomy significantly improved OS (HR 0.54 (0.36-0.80)). CONCLUSIONS: The incidence of SIAs almost doubled in the past 20 years, with no improvement in OS. This retrospective non-randomized study suggests the use of adjuvant chemotherapy for stage III disease and first-line CAPOX for metastatic patients. For selected oligometastatic patients, a metastasectomy may be considered. MMR-status testing could aid in clinical decision-making.

Small intestinal angiosarcoma on clinical presentation, diagnosis, management and prognosis: A case report and review of the literature.

BACKGROUND: Angiosarcoma is a highly malignant soft-tissue sarcoma derived from vascular endothelial cells that mainly occurs in the skin and subcutaneous tissues. Small-intestinal angiosarcomas are rare, and the prognosis is poor. CASE SUMMARY: We reported a case of primary multifocal ileal angiosarcoma and analyze previously reported cases to improve our understanding of small intestinal angiosarcoma. Small intestinal angiosarcoma is more common in elderly and male patients. Gastrointestinal bleeding, anemia, abdominal pain, weakness, and weight loss were the common symptoms. CD31, CD34, factor VIII-related antigen, ETS-related gene, friend leukemia integration 1, and von Willebrand factor are valuable immunohistochemical markers for the diagnosis of small-intestinal angiosarcoma. Small-intestinal angiosarcoma most commonly occurs in the jejunum, followed by the ileum and duodenum. Radiation and toxicant exposure are risk factors for angiosarcoma. After a definite diagnosis, the mean and median survival time was 8 mo and 3 mo, respectively. Kaplan-Meier survival analysis showed that age, infiltration depth, chemotherapy, and the number of small intestinal segments invaded by tumor lesions were prognostic factors for small intestinal angiosarcoma. Multivariate Cox regression analysis showed that chemotherapy and surgery significantly improved patient prognosis. CONCLUSION: Angiosarcoma should be considered for unexplained melena and abdominal pain, especially in older men and patients with a history of radiation exposure. Prompt treatment, including surgery and adjuvant chemotherapy, is essential to prolonging patient survival.

Characteristics and outcome of patients with small bowel adenocarcinoma (SBA).

BACKGROUND: Small bowel adenocarcinoma (SBA) remains a rare malignancy accounting for less than 5% of all the gastrointestinal tract cancers. However, only limited data and expert guidelines are available for this entity. As a result, treatment concepts are predominantly derived from colorectal cancer. METHODS: To substantiate data on the course of disease, diagnosis and treatment of SBA, we performed a population-based analysis from a Bavarian population of 2.2 million people. RESULTS: We identified 223 patients with SBA. Mean age at diagnosis was 67.8 years and patients were diagnosed rather late (34.5% UICC stage IV). Largest proportion of these patients were diagnosed with adenocarcinoma of the duodenum (132 patients, 59.2%) and most patients were diagnosed with late stage cancer, stage IV (70 patients, 31.4%). With respect to treatment, most patients underwent primary surgery (187 patients, 84.6%). Systemic therapy seemed to have an impact in UICC stage IV patients but not in UICC stage IIB or III. The 5-year survival rate was 29.0%. This was significantly less compared to colon cancer in the same cohort, which was 50.0%. Furthermore, median survival of patients with small bowel cancer was only 2.0 years (95% CI 1.4-2.5) compared to 4.9 years (95% CI 4.8-5.1) of patients with colon cancer. CONCLUSION: SBA showed a distinct epidemiology compared to colon cancer. Thus, data acquisition particularly on systemic treatment are paramount, with the objective to complement the available guidelines.

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.

How to Manage Small Intestine (Jejunal and Ileal) Neuroendocrine Neoplasms Presenting with Liver Metastases?

PURPOSE OF REVIEW: Small intestinal neuroendocrine neoplasms (siNENs) are slowly growing tumours with a low malignant potential. However, more than half of the patients present with distant metastases (stage IV) and nearly all with locoregional lymph node (LN) metastases at the time of surgery. The value of locoregional treatment is discussed controversially. RECENT FINDINGS: In stage I to III disease, locoregional surgery was currently shown to be curative prolonging survival. In stage IV disease, surgery may prolong survival in selected patients with the chance to cure locoregional disease besides radical/debulking liver surgery. It may improve the quality of life and may prevent severe local complications resulting in a state of chronic malnutrition and severe intestinal ischaemia or bowel obstruction. Locoregional tumour resection offers the opportunity to be curative or to focus therapeutically on liver metastasis, facilitating various other therapeutic modalities. Risks and benefits of the surgical intervention need to be balanced individually.

Clinical features, treatment, and prognosis of different histological types of primary small bowel adenocarcinoma: A propensity score matching analysis based on the SEER database.

PURPOSE: This aim of this study was to provide a comprehensive understanding of the clinical characteristics, treatment, and prognosis of patients with small bowel adenocarcinoma (SBA), mucinous small bowel adenocarcinoma (MSBA), and signet ring cell carcinoma of the small bowel (SRCSB). METHODS: Information on patients with SBA, MSBA, and SRCSB (2004-2015) was obtained from the Surveillance, Epidemiology and End Results (SEER) database. Cox proportional hazards models and Kaplan-Meier curves were used for the survival analyses. Propensity-score matching (PSM) was implemented to determine the differences among these tumors. RESULTS: In all, 3697 patients with SBA (n = 3196), MSBA (n = 325) and SRCSB (n = 176) were ultimately eligible for this study. Poor differentiation, local invasion, and lymph node metastasis were more likely to be observed in SRCSB than in SBA and MSBA. Surgery was the most common treatment modality in all groups. The prognosis of SBA was similar to that of MSBA, but better than that of SRCSB in both unmatched and matched cohorts. M stage, surgery, and chemotherapy were identified as independent predictors of survival in all patients. Surgery and chemotherapy could significantly improve outcomes in all groups before and after PSM. Radiotherapy was associated with a survival benefit in patients with SBA, but this trend was not maintained after PSM. Survival advantages of SBA and MSBA were remarkable in the stratified analysis of surgery after PSM. CONCLUSION: Patients with SRCSB had the worst prognosis among all histological types examined. However, surgery and chemotherapy could improve patients survival, regardless of histological type.

Frequency, prognosis and treatment modalities of newly diagnosed small bowel cancer with liver metastases.

BACKGROUND: Population-based analysis for the liver metastases of small bowel cancer is currently lacking. This study aimed to analyze the frequency, prognosis and treatment modalities for newly diagnosed small bowel cancer patients with liver metastases. METHODS: Patients with small bowel cancer diagnosed from 2010 to 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Binary logistic regression analysis was performed to determine predictors for the presence of liver metastases at diagnosis. Kaplan-Meier method and Cox regression analyses were performed for survival analyses. RESULTS: A total of 1461 small bowel cancer patients with liver metastases at initial diagnosis were identified, representing 16.5% of the entire set and 63.9% of the subset with metastatic disease to any distant site. Primary tumor with poorer histological type, larger tumor size, later N staging, more extrahepatic metastatic sites, and tumor on lower part of small intestine had increased propensity of developing liver metastases. The combined diagnostic model exhibited acceptable diagnostic efficiency with AUC value equal to 0.749. Patients with liver metastases had significant poorer survival (P < 0.001) than those without liver metastases. In addition, combination of surgery and chemotherapy (HR = 0.27, P < 0.001) conferred the optimal survival for patients with adenocarcinoma, while the optimal treatment options for NEC and GIST seemed to be surgery alone (HR = 0.24, P < 0.001) and chemotherapy alone (HR = 0.08, P = 0.022), respectively. CONCLUSIONS: The combined predictor had a good ability to predict the presence of liver metastases. In addition, those patients with different histologic types should be treated with distinct therapeutic strategy for obtaining optimal survival.

Small Bowel Adenocarcinomas: Impact of Location on Survival.

BACKGROUND: Proximal (duodenal) small bowel adenocarcinomas have a worse prognosis than distal (jejuno-ileal) tumors, but differences in patient, tumor, and treatment factors between locations remain unclear. METHODS: Patients in the National Cancer Database with surgically resected pathologic stage I-IV small bowel adenocarcinomas between 2004 and 2015 were analyzed. Clinical stage IV patients were excluded. RESULTS: Proximal tumors (n = 3767) were more likely to be higher grade (OR 1.52, CI 1.22-1.85 for moderately; OR 1.83, CI 1.49-2.33 for poorly differentiated, P < 0.01 for both) and have positive lymph nodes (OR 2.04, CI 1.30-3.23, P < 0.01), while distal tumors (n = 3252) were likely to be larger (OR 1.31, CI 1.07-1.60 for size > 5 cm, P < 0.01). Proximal tumors were associated with worse overall survival (OS) and stage-specific survival compared with distal tumors (all P < 0.01). Cox regression analysis of the entire cohort showed worse survival with community versus academic cancer programs, higher comorbidity scores, pathologic stage IV, poorly differentiated histology, positive nodal or margin status, and proximal location, while female gender, larger tumor size, and chemotherapy predicted better survival. On separate Cox regression analyses of each location, neoadjuvant chemotherapy was associated with better OS in the proximal cohort (HR 0.70, CI 0.55-0.88, P < 0.01), while adjuvant chemotherapy was associated with better OS for both proximal (HR 0.49, CI 0.42-0.57, P < 0.01) and distal tumors (HR 0.68, CI 0.57-0.81, P < 0.01). CONCLUSIONS: Proximal small bowel adenocarcinomas are associated with worse overall and stage-specific survival. This may be due to tumor biologic differences as proximal tumors were more likely to have higher grade. Future studies should further investigate differences between proximal and distal tumors to guide targeted treatment algorithms.

Spontaneous partial regression of a microcystic jejunal mesenteric lymphangioma and a proposed management algorithm.

Mesenteric lymphangiomas are relatively rare, with clinical symptoms ranging from an asymptomatic presentation to an acute abdomen. The natural history and biological behaviour of this entity can range from slow indolent lesions to aggressive tumours with a risk of malignant transformation. Spontaneous regression of a mesenteric lymphangioma is rare. We herein report a case of a jejunal mesenteric lymphangioma that was initially detected incidentally in an asymptomatic patient with a subsequent sudden increase in size with resulting surrounding mass effect after 9 months and a spontaneous partial regression at surgical resection. Our case is the first reported case which outlines a period in the natural history and evolution of microcystic mesenteric lymphangioma, illustrating the sudden enlargement likely attributable to spontaneous and self-limiting haemorrhage and subsequent partial regression at surgical resection. We thenceforth propose a possible management algorithm for adult patients with mesenteric lymphangiomas.

Clinical Outcomes of Small Bowel Adenocarcinoma.

BACKGROUND: Small bowel adenocarcinomas (SBAs) are rare tumors. Management of SBA is extrapolated from colorectal cancer treatments. Recent evidence suggests that the biology and molecular features of SBA differ from colorectal cancer. The aim of this study was to evaluate the management and outcome of SBA patients. PATIENTS AND METHODS: The National Cancer Data Base (NCDB) was queried for patients with SBA between 2004 and 2013 using ICD-O-3 histology code 8140/3 and topography codes C17.0, C17.1, C17.2, C17.8, and C17.9. Univariate and multivariate survival analyses were conducted to analyze the association between SBA location and overall survival (OS) stratified by stage. Treatment outcomes of surgery, radiation, and systemic therapy were compared. RESULTS: A total of 7954 SBA patients were identified; duodenum (D) 4607 (57.9%), jejunum (J) 1241 (15.6%), ileum (I) 857 (10.8%), and unspecified 1249 (15.7%). A total of 53.6% patients were male, and 76.6% white. Median age was 66 years. D mostly presented as stage IV disease (37.6%), J as stage II (34.5%) and IV disease (33.8%), and I as stage II (32.2%) and III (30.3%) disease (P < .001). Grade distribution was similar among D, J, and I; the majority were moderately differentiated (40.8%-55.0%), followed by poorly differentiated (30.9%-35.8%) and well differentiated (6.0%-12.4%) (P < .001). D underwent surgery (50.2%) less often than J (90.8%) and I (94.5%) (P < .001). Adjuvant radiation was provided in 8.5% of D, 2.6% of J, and 2.1% of I (P < .001). Adjuvant chemotherapy was provided in 21.9% of D, 50.2% of J, and 42.0% of I (P < .001). The rate of adjuvant chemotherapy was the highest in patients with stage III SBA, and was as follows: D (43.4%), J (65.4%), and I (63.6%) (P < .001). In univariate and multivariate analyses of all patients, adjuvant chemotherapy was associated with improved OS in stage II-III SBA patients. J had the best 5-year OS rate (42.0%; 95% confidence interval, 38.8-45.1, P < .001), and D had the worst (23.0%; 95% confidence interval, 21.6-24.2, P < .001). In multivariate analysis stratified by stage, chemotherapy was associated with improved OS in patients with stage II-IV SBA. CONCLUSION: Most SBA patients present with stage IV disease. D underwent surgery less often than J and I. Stage II and III D received adjuvant chemotherapy less often compared to stage II and III J and I. Adjuvant chemotherapy was associated with improved OS in patients with stage II-III disease. J had the best 5-year OS rate, and D had the worst.

Multicenter retrospective analysis of the clinicopathologic features of monomorphic epitheliotropic intestinal T-cell lymphoma.

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a provisional entity in the 2017 World Health Organization classifications. To further elucidate the clinicopathologic features of this new disease, we carried out a retrospective, multicenter analysis of 42 patients with MEITL. The median age of the patients was 59 years (range, 20-84 years), and 27 patients (64 %) were male. Thirty-two patients (76 %) were Ann-Arbor stages I-II and 28 (67 %) were Lugano stages I-II1&2. The most frequent site of involvement was the jejunum (N = 21). Most cases expressed CD8 (79 %) and CD56 (95 %) and did not express CD30 (5 %) or EBER (0 %). The median progression-free survival was 6.9 months (95 % CI 4.3-9.6); the median OS was 14.8 months (2.4-27.2). Thirty-two patients (76 %) underwent surgery and 37 (88 %) received chemotherapy. A complete response (CR) rate was 38 %. Sixteen patients had undergone autologous stem cell transplantation (ASCT). Relapse or progression was documented in 24 cases, most frequently in the primary site (N = 23). Four cases showed central nervous system relapse. Age over 55 years, poor performance scale, advanced Lugano stage (IIE-IV), not achieving CR, and not receiving ASCT were associated with inferior OS. While the optimal management of MEITL remains undetermined, achieving CR and consolidative ASCT seem essential. As CHOP might be insufficient for achieving CR, more efficient combinations should be investigated. Additionally, considering the frequent local failure and CNS relapse, novel therapeutic approaches are required to improve survival.

Primary Jejunal adenocarcinoma - An unsuspected culprit.

Primary Small bowel adenocarcinoma, a rare entity and having varied clinical presentation, makes its clinical detection a diagnostic challenge. Moreover, its true prevalence in sub-continent population has not yet been established, which makes it more difficult for its detection. We present the case of a 60 year old male who came with abdominal pain and weight loss for two years as the only symptoms. A series of tests in the two year period remained inconclusive. Later Computed tomography showed a suspicious mass at the terminal ileum. On exploration, there was a grossly dilated jejunal loop due to stricture one foot from ligament of Trietz and mesenteric lymphadenopathy. En-bloc resection of jejunum with suspicious of malignancy was done and primary end to end anastomosis was made. Histopathology and follow up metastatic workup showed poorly differentiated adenocarcinoma of jejunum with T3N1M0. Small bowel malignancy should also be kept in mind, when managing patients with weight loss of unknown origin.

The characteristics and outcomes of small bowel adenocarcinoma: a multicentre retrospective observational study.

BACKGROUND: Small bowel adenocarcinoma (SBA) is a rare malignancy that accounts for 1-2% of gastrointestinal tumours. We investigated the clinical characteristics, outcomes, and prognostic factors of primary SBA. METHODS: We retrospectively analysed the characteristics and clinical courses of 205 SBA patients from 11 institutions in Japan between June 2002 and August 2013. RESULTS: The primary tumour was in the duodenum and jejunum/ileum in 149 (72.7%) and 56 (27.3%) patients, respectively. Sixty-four patients (43.0%) with duodenal adenocarcinoma were asymptomatic and most cases were detected by oesophagogastroduodenoscopy (EGD), which was not specifically performed for the detection or surveillance of duodenal tumours. In contrast, 47 patients (83.9%) with jejunoileal carcinoma were symptomatic. The 3-year survival rate for stage 0/I, II, III, and IV cancers was 93.4%, 73.1%, 50.9%, and 15.1%, respectively. Multivariate analysis revealed performance status 3-4, high carcinoembryonic antigen, high lactate dehydrogenase (LDH), low albumin, symptomatic at diagnosis, and stage III/IV disease were independent factors for overall survival (OS). Ten patients (18.5%) with stage IV disease were treated with a combination of resection of primary tumour, local treatment of metastasis, and chemotherapy; this group had a median OS of 36.9 months. CONCLUSIONS: Although most SBA patients were diagnosed with symptomatic, advanced stage disease, some patients with duodenal carcinoma were detected in early stage by EGD. High LDH and symptomatic at diagnosis were identified as novel independent prognostic factors for OS. The prognosis of advanced SBA was poor, but combined modality therapy with local treatment of metastasis might prolong patient survival.

Primary small bowel adenocarcinoma: current view on clinical features, risk and prognostic factors, treatment and outcome.

Small bowel adenocarcinoma (SBA) is a rare but increasing cause of gastrointestinal malignancy, being both a diagnostic and therapeutic challenge. The goal of treatment is margin negative resection of a lesion and local lymphadenectomy, followed by modern adjuvant chemotherapy combinations in selected cases. Improved outcomes in patients with SBA are encouraging, but elucidation of mechanisms of carcinogenesis and risk factors as well as improved treatment for this malignancy is very needed.

Synchronous quintuple primary gastrointestinal tract malignancies: Case report.

Multiple primary malignancy is defined as two or more malignancies detected in an individual person. In particular, synchronous quintuple primary malignancy is extremely rare. A 52-year-old male with anal pain and intermittent blood-tinged stool was diagnosed with malignancies in the stomach, jejunum, ascending colon, transverse colon and rectum. He underwent a subtotal gastrectomy, segmental resection of the jejunum and total protocolectomy with end ileostomy. The postoperative pathologic findings were moderate differentiated gastric adenocarcinoma (pT1bN0M0, pStageIA), combined adenocarcinoma and neuroendocrine carcinoma of the jejunum (pT3N0M0, pStageIIA), three mucinous adenocarcinoma of the ascending colon (pT3N0M0, pStageIIA), transverse colon (pT1N0M0, pStageI) and rectum (pT3N1aM0, pStageIIIB). The tumors did not lack MLH-1 and MSH-2 expression, as the markers (bat26, D5S346, bat25, D2S123) suggest MSI-H presence. Adjuvant chemoradiotherapy was started according to regimen, FOLFOX 4 for advanced rectal cancer. Six years post-operation, the patient is currently attending regular follow-ups without recurrence or metastasis.

[A Case of Perforative Peritonitis Due to Intestinal Metastasis from Lung Cancer].

We here describe a case of an acute peritonitis due to perforation of a small intestine tumor metastasized from a lung cancer. A 66-year-old man who had undergone a bladder cancer procedure 2 years ago and was hospitalized for the second operation, complained sudden abdominal pain. An enhanced abdominal CTrevealed a small amount of free gas and ascites in the abdominal cavity. On the same day, emergency exploratory surgery was performed with the diagnosis of perforative peritonitis. A laparotomy revealed a jejunal tumor with perforation 40 cm distal from the Treitz ligament. After surgery, the patient confessed that he had got a notice of the recurrence of lung cancer which had been treated 9 years ago. The pathological result indicated the lesion was metastasis from lung cancer. Although small intestinal metastatic tumor from lung cancer is rare, it should be considered when acute abdomen is observed.

Treatment and Survival of Small-bowel Adenocarcinoma in the United States: A Comparison With Colon Cancer.

BACKGROUND: Small-bowel adenocarcinoma is rare and fatal. Because of data paucity, there is a tendency to extrapolate treatment from colon cancer, particularly in the adjuvant stetting. OBJECTIVE: The purpose of this study was to evaluate the current surgical and adjuvant treatments of small-bowel adenocarcinoma and compare with colon cancer. DESIGN: This was a retrospective cohort study. SETTINGS: The linked Surveillance, Epidemiology, and End Results and Medicare database was used at a tertiary referral hospital. PATIENTS: Patients with small-bowel adenocarcinoma and colon cancer identified from 1992 to 2010, using International Classification of Diseases for Oncology, 3 Revision, site, behavior, and histology codes were included. MAIN OUTCOME MEASURES: Overall survival and cancer-specific survival were estimated using the Kaplan-Meier method and competing risk analysis. RESULTS: A total of 2123 patients with small-bowel adenocarcinoma and 248,862 patients with colon cancer were identified. Five-year overall survival rates for patients with small-bowel adenocarcinoma and colon cancer were 34.9% and 51.5% (p < 0.0001). A total of 1550 patients with small-bowel adenocarcinoma (73.0%) underwent surgery, compared with 177,017 patients with colon cancer (71.1%). The proportion of patients who received chemotherapy was similar, at 21.3% for small bowel and 20.0% for colon. In contrast to colon cancer, chemotherapy did not improve overall or cancer-specific survival for patients with small-bowel adenocarcinoma, regardless of stage. Predictors of poor survival for small-bowel adenocarcinoma on multivariate analysis included advanced age, black race, advanced stage, poor tumor differentiation, high comorbidity index, and distal location. Chemotherapy did not confer additional survival benefit compared with surgery alone (HR, 1.04 (95% CI, 0.90-1.22)). LIMITATIONS: This was a retrospective review. The reliance on Medicare data limited granularity and may have affected the generalizability of the results. CONCLUSIONS: The prognosis for small-bowel adenocarcinoma is worse than that for colon cancer, and only surgery improves survival. In contrast to colon cancer, a survival benefit from current chemotherapy regimens for small-bowel adenocarcinoma is not seen, suggesting that it may be overused and needs more rigorous study.