Molecular characterisation and cetuximab-based treatment in a patient with refractory small bowel adenocarcinoma

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

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

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

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

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

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

Anti epidermal growth factor receptor therapy in small bowel adenocarcinoma: Case report and literature review

RATIONALE

Small bowel adenocarcinoma (SBA) is an uncommon gastrointestinal cancer, thus limited data about treatment for advanced disease are available. The lack of specific guidelines has justified the use of therapeutic protocols usually applied in advanced colorectal cancer. Few and preliminary data have suggested possible clinical benefit from the use of target therapy such as bevacizumab and cetuximab.

PATIENT CONCERNS

We present the case of a young woman who was admitted to the emergency department for acute abdominal pain, nausea, and vomiting related to a jejunal stenosis.

DIAGNOSES

An enteroscopy with jejunal biopsy showed poorly differentiated cancerous cells suggestive for primary intestinal cancer. There were no signs of metastatic disease at radiological evaluation. A jejunal resection was subsequently carried out and the diagnosis of mucinous adenocarcinoma of the jejunum was confirmed.

INTERVENTIONS

The computed tomography scan performed 1 month after surgery showed metastatic disease. Therefore, the patient received combined protocols of chemotherapy and either bevacizumab or the anti-epidermal growth factor receptor (EGFR) panitumumab.

OUTCOMES

A partial response (PR) was achieved with Folfox plus panitumumab and a maintenance therapy with panitumumab is being conducted with a mild toxicity and a progression free survival of 19 months since the beginning of panitumumab.

LESSONS

This is, to the best of our knowledge, the first report in the literature of a patient with SBA who has benefitted from panitumumab with an overall survival of 83 months.

Clinical use of molecular targeted agents for primary small bowel adenocarcinoma: A multicenter retrospective cohort study by the Osaka Gut Forum

Primary small bowel adenocarcinoma (SBA) is a rare cancer for which effective treatment strategies have not yet been established. The results of previous retrospective studies suggest that chemotherapy contributes to a longer survival time in patients with SBA. However, there are few case reports about the efficacy of molecular targeted agent-containing chemotherapy for SBA. In the present study, the treatment and follow-up data of patients with SBA who received chemotherapy with or without molecular targeted agents were retrospectively analyzed. Each patient was treated in one of ten hospitals participating in the Osaka Gut Forum between April 2006 and March 2014. The following factors were evaluated: Age, sex, Eastern Cooperative Oncology Group performance status (PS), tumor location, tumor differentiation, chemotherapy regimen, resection of primary tumor, tumor biomarker expression, distant metastasis, best response under chemotherapy, time to disease progression, subsequent treatments, survival status and treatment toxicity. A total of 27 patients (17 males and 10 females; mean age, 63.4 years old; range, 36-83 years old) received chemotherapy due to non-curative tumor resection, unresectable tumor or post-operative recurrence. The median overall survival time was 14.8 months (range, 2-58 months). A univariate analysis revealed a PS of 0 (P=0.0228) and treatment with platinum-based chemotherapy (P=0.0048) were significant factors for an improved prognosis. An age-adjusted multivariate analysis also revealed that a platinum-based regimen was a significant positive prognostic factor (P=0.0373). Molecular targeted agents were administered to 8 patients, for whom it was their first- or second-line therapy. Among the 17 patients who received oxaliplatin-based chemotherapy as a first-line chemotherapy, a PS of 0 (P=0.0255) and treatment with bevacizumab (P=0.0121) were significant positive prognostic factors. Toxicities higher than Grade 3 occurred in 8/27 patients with SBA; however, serious side effects due to the molecular targeted agents were not experienced. The results of the present study indicate that chemotherapy containing molecular targeted agents is a well-tolerated and effective treatment option for SBA.

Small bowel adenocarcinoma of the jejunum: a case report and literature review

Background

In practice, small bowel cancer is a rare entity. The most common histologic subtype is adenocarcinoma. Adenocarcinoma of the small bowel (SBA) is challenging to diagnose, often presents at a late stage and has a poor prognosis. The treatment of early-stage SBA is surgical resection. No standard protocol has been established for unresectable or metastatic disease.

Case presentation

We report here on a 26-year-old man with SBA in the jejunum, lacking specific symptoms and with a delay of 6 months in diagnosis. The diagnosis was finally achieved with a combination of balloon-assisted enteroscopy, computed tomography scans, positron emission computed tomography scans and the values of carcino-embryonic antigen and carbohydrate antigen 19-9. The patient underwent segmental intestine with lymph node resection, followed by eight cycles of FOLFOX palliative chemotherapy with good tolerance. As of the 11-month postoperative follow-up, there has been no evidence of recurrent disease.

Conclusions

This case is reported to arouse a clinical suspicion of SBA in patients with abdominal pain of unknown cause. We also provided evidence in this case of a response to palliative chemotherapy with FOLFOX. Because the incidence of SBA is very low, there is a need for further studies to evaluate the possible application of newer investigative agents and strategies to obtain a better outcome within the framework of international collaborations.

Clinicopathologic and prognostic associations of KRAS and BRAF mutations in small intestinal adenocarcinoma

Activating KRAS and/or BRAF mutations have been identified as predictors of resistance to anti-epidermal growth factor receptor (EGFR) chemotherapy in colorectal cancer. But the status of KRAS and BRAF mutations and their clinicopathologic and prognostic significance has not been extensively evaluated in small intestinal adenocarcinomas. In this work, the KRAS and BRAF genes in 190 surgically resected small intestinal adenocarcinoma cases were sequenced and their association with various clinicopathologic variables, including survival of the patients, was analyzed. KRAS or BRAF mutations were observed in 63 (33%) cases. Sixty-one cases had KRAS mutations and 2 had BRAF mutations and the two types of mutation were mutually exclusive. The majority of KRAS mutations were G>A transition (43/61 cases, 71%) or p.G12D (31/61 cases, 51%). The patients with mutant KRAS tended to have higher pT classifications (P=0.034) and more frequent pancreatic invasion (P=0.020) than those with wild-type KRAS. Multivariate logistic regression analysis showed that certain mutated KRAS subtypes (G>A transitions and G12D mutations) were significantly correlated with higher pT classification (P=0.015 and 0.004, respectively) than wild-type KRAS and other KRAS mutations. The patients with KRAS or BRAF mutation had a tendency to shorter overall survival than those with wild-type KRAS and BRAF (P=0.148), but subgroup analysis demonstrated the patients with KRAS mutations showed worse survival (median, 46.0 months; P=0.046) than those with wild-type KRAS (85.4 months) in lower pT classification (pT1-pT3) group. In summary, KRAS and, infrequently, BRAF mutations are observed in a subset of small intestinal adenocarcinomas, and are associated with higher pT classification and more frequent pancreatic invasion. KRAS mutation is a poor prognostic predictor in patients with lower pT classification tumors. Anti-EGFR targeted therapy could be applied to about two-thirds of small intestinal adenocarcinoma patients, namely those with wild-type KRAS and BRAF if they have metastatic disease, similar to colorectal cancer patients.

Advanced small bowel adenocarcinoma: Molecular characteristics and therapeutic perspectives

Small bowel cancer represents less than 5% of all gastrointestinal cancers, while small bowel adenocarcinoma (SBA) accounts for about one third of all cancers of the small bowel. Although SBA frequently appears sporadically, some diseases are risk factors, such as Crohn's disease and some genetic predispositions to cancer. Progress in the identification of molecular alterations suggests some similarities in carcinogenesis between SBA and colorectal cancer. Evidence levels for the treatment and prognosis of these tumors are insufficient because of the scarcity of this disease and the absence of randomized trials. Chemotherapy based on fluoropyrimidine plus a platinum salt appears to be the most effective treatment regimen in non-randomized prospective trials for advanced SBA. Targeted therapy, against the angiogenic pathway or the epidermal growth factor receptor (EGFR) pathway, for example, is not yet established, but seems promising given the over-expression of vascular epithelial growth factor (VEGF)-A or EGFR observed in SBA. Phase I and II studies are currently evaluating the safety and efficacy of these targeted therapies in SBA treatment. The low incidence of SBA should promote the development of international collaborations to improve our knowledge of the biological mechanisms underlying these tumors and to set up therapeutic trials.

Prognostic implications of thymidylate synthase gene polymorphisms in patients with advanced small bowel adenocarcinoma treated with first-line fluoropyrimidine-based chemotherapy

Thymidylate synthase (TS) gene polymorphisms such as tandem repeat (TR) polymorphisms and single-nucleotide polymorphisms (SNPs) affect transcriptional efficiency of the TS gene and may be prognostic markers for fluoropyrimidine-based therapy in various gastrointestinal cancers. However, data for TS polymorphisms on clinical outcomes in advanced small bowel adenocarcinoma (SBA) are limited. We retrospectively enrolled 58 locally advanced/metastatic SBA patients treated with first-line fluoropyrimidine-based chemotherapy and analyzed the relationship between TS genotypes and clinical outcomes in 30 patients who were available for tumor tissue. Based on TR polymorphisms and a G>C SNP in the promoter region of the TS gene, 74% of patients had high TS expression genotypes (2R/3RG, 3RG/3RC, 3RG/3RG); the remainder had low TS expression genotypes (2R/2R, 2R/3RC, 3RC/3RC). After a median follow-up of 48.8 months, median progression-free survival (PFS) and overall survival (OS) in all patients were 6.0 and 11.3 months, respectively. However, patients with low TS expression genotypes had better median PFS (12.8 vs. 4.3 months, P=0.027) and OS (28.8 vs. 8.9 months, P=0.025) than those with high TS expression genotypes. In multivariate analysis, poor Eastern Cooperative Oncology Group performance status [hazard ratio (HR), 2.85; 95% CI, 1.02-7.93] and high TS expression genotypes (HR, 3.49; 95% CI, 1.13-10.78) were independent prognostic factors for worse OS. Therefore, TS genotypes, based on a G>C SNP in the TR sequence of the TS gene, may be a useful biomarker for predicting outcomes for fluoropyrimidine-based chemotherapy in patients with locally advanced/metastatic SBA.

Extra-ampullary duodenal adenocarcinoma

Extra-ampullary duodenal adenocarcinomas are rare, and when studied, frequently have been grouped with jejunoileal adenocarcinomas. Nevertheless, anecdotal experiences suggest that these neoplasms may present 2 or more distinct phenotypes. To better characterize these neoplasms, we performed a retrospective review of 38 cases with a special focus on the morphologic and immunophenotypic characteristics and their clinicopathologic significance. Our cohort of extra-ampullary duodenal adenocarcinomas was classified on the basis of the morphologic features into gastric type (n=19, 50%), intestinal type (n=14, 37%), pancreaticobiliary type (n=2, 5%), and others (n=3, 8%). Most gastric-type adenocarcinomas (n=18, 95%) developed in the proximal duodenum, whereas the other types were located equally in the proximal and distal duodenum. Intestinal-type dysplasia was present at the periphery of 8 (57%) intestinal-type adenocarcinomas, and 8 (42%) gastric-type adenocarcinoma were associated with gastric-type dysplasia. Gastric foveolar metaplasia (n=12) and Brunner gland hyperplasia (n=10) were exclusively recognized adjacent to gastric-type adenocarcinomas. Notably, intestinal-type histology and the absence of lymph node metastasis were significantly associated with favorable disease-free survival in univariate and multivariate analyses. In summary, this study demonstrated that 2 major subsets of extra-ampullary duodenal adenocarcinoma, intestinal type and gastric type, are associated with distinct histopathologic features and clinical behavior.

Small bowel adenocarcinoma - terra incognita: A demand for cross-national pooling of data

To date, due to the rarity, tumor biology and carcinogenesis of small bowel adenocarcinoma (SBA), the disease has been explored insufficiently and immunophenotyping and molecular characterization have not been finalized. This knowledge gap consecutively leads to an overt lack of diagnostic and therapeutic recommendations. In the current study, we provide our experience with the treatment of SBA, and demand for cross-national data pooling to enable unlimited information transfer and higher powered study. A comprehensive database of all patients with SBA was established and consecutively reviewed for clinicopathohistological data, information concerning preoperative evaluation, surgical and chemotherapeutical treatment, as well as outcome parameters. Patients underwent curative intended surgery (42.4%; n=14), adjuvant chemotherapy (CTX) following resection (36.4%; n=12) or palliative care (21.2%; n=7). The majority of patients were diagnosed at an advanced disease stage (pT3, 36.4%; pT4, 39.4%) and the duodenum was the most common tumor site (57.1%; n=20). Complete surgical resection was achieved in 88.5% of patients, while postoperative complications occurred in 19.4%. Within a mean follow-up period of 31.4 months, 17 patients succumbed to the disease following a median survival time of 11 months. Mean overall survival (OS) was 47.4, 25.3 and 9.8 months for surgically, surgically and chemotherapeutically and palliatively treated patients, respectively. Early surgical resection remains the mainstay in the treatment of localized SBA, since it is associated with a prolongation of OS. The role of neoadjuvant and adjuvant CTX has not yet been defined. Thus, since no consensus exists on the adequate treatment of these malignancies, we demand an international collaboration and cross-national data pooling to pave the way for the implementation of evidence-based standard care operating procedures.

Small bowel adenocarcinomas--existing evidence and evolving paradigms

Small bowel cancers account for 3% of all gastrointestinal malignancies and small bowel adenocarcinomas represent a third of all small bowel cancers. Rarity of small bowel adenocarcinomas restricts molecular understanding and presents unique diagnostic and therapeutic challenges. Better cross-sectional imaging techniques and development of enteroscopy and capsule endoscopy have facilitated earlier and more-accurate diagnosis. Surgical resection remains the mainstay of therapy for locoregional disease. In the metastatic setting, fluoropyrimidine and oxaliplatin-based chemotherapy has shown clinical benefit in prospective non-randomized trials. Although frequently grouped under the same therapeutic umbrella as large bowel adenocarcinomas, small bowel adenocarcinomas are distinct clinical and molecular entities. Recent progress in molecular characterization has aided our understanding of the pathogenesis of these tumours and holds potential for prospective development of novel targeted therapies. Multi-institutional collaborative efforts directed towards cogent understanding of tumour biology and designing sensible clinical trials are essential for developing improved therapeutic strategies. In this Review, we endeavour to outline an evidence-based approach to present-day management of small bowel adenocarcinoma, describe contemporary challenges and uncover evolving paradigms in the management of these rare 'orphan' neoplasias.