The role of 68-Ga-DOTATOC CT-PET in surgical tactic for gastric neuroendocrine tumors treatment: our experience: a case report

Gastric neuroendocrine neoplasms

Gastric neuroendocrine neoplasms (gNENs) display peculiar site-specific features among all NENs. Their incidence and prevalence have been rising in the past few decades. gNENs comprise gastric neuroendocrine carcinomas (gNECs) and gastric neuroendocrine tumours (gNETs), the latter further classified into three types. Type I anatype II gNETs are gastrin-dependent and develop in chronic atrophic gastritis and as part of Zollinger-Ellison syndrome within a multiple endocrine neoplasia type 1 syndrome (MEN1), respectively. Type III or sporadic gNETs develop in the absence of hypergastrinaemia and in the context of a near-normal or inflamed gastric mucosa. gNECs can also develop in the context of variable atrophic, relatively normal or inflamed gastric mucosa. Each gNEN type has different clinical characteristics and requires a different multidisciplinary approach in expert dedicated centres. Type I gNETs are managed mainly by endoscopy or surgery, whereas the treatment of type II gNETs largely depends on the management of the concomitant MEN1. Type III gNETs may require both locoregional approaches and systemic treatments; NECs are often metastatic and therefore require systemic treatment. Specific data regarding the systemic treatment of gNENs are lacking and are derived from the treatment of intestinal NETs and NECs. An enhanced understanding of molecular and clinical pathophysiology is needed to improve the management and outcomes of patients' gNETs.

Recurrent gastric antral vascular ectasia: a single center experience

INTRODUCTION

Gastric antral vascular ectasia (GAVE) is a rare cause of chronic or acute gastrointestinal bleeding. This condition accounts for ∼4% of upper gastrointestinal bleeding cases. This disease is often associated with systemic diseases, such as liver cirrhosis, chronic kidney failure, autoimmune conditions, diabetes mellitus, hypothyroidism, and cardiovascular diseases. However, its etiopathogenesis remains controversial.

MATERIALS AND METHOD

We retrospectively reviewed the cases of GAVE treated at our digestive surgery unit. A total of nine patients were identified with a male/female ratio of 1.25:1 and an average age of 75.51 years (SD ± 9.85). All patients underwent endoscopic argon plasma coagulation (APC) treatment. At the time of the review, data on eight patients were available after 36 months of follow-up.

RESULTS

APC appears to be safe and effective for hemostasis of bleeding vascular ectasia. Only one (11.1%) patient required surgical intervention due to hemodynamic instability after multiple unsuccessful endoscopic treatments. No intraoperative and postoperative complication or bleeding relapse was experienced.

DISCUSSION

Based on our findings, we concluded that endoscopic APC is technically simple, but requires multiple re-interventions due to the incidence of relapses. Furthermore, larger randomized studies should be conducted to assess the role of elective surgery as the first intervention in stable patients with severe pathology and the timing of surgery after failed endoscopic treatment.

Gastric Neuroendocrine Tumors (g-NETs): A Systematic Review of the Management and Outcomes of Type 3 g-NETs

PURPOSE

to collect data from real-life experiences of the management of type 3 g-NETs and identify possible prognostic factors that may impact the decision-making process.

METHODS

We performed a systematic review of the literature on type 3 g-NET management using the PubMed, MEDLINE, and Embase databases. We included cohort studies, case series, and case reports written in the English language.

RESULTS

We selected 31 out of 556 articles from between 2001 and 2022. In 2 out of the 31 studies, a 10 mm and 20 mm cut-off size were respectively associated with a higher risk of gastric wall infiltration and/or lymph node and distant metastasis at diagnosis. The selected studies reported a higher risk of lymph node or distant metastasis at diagnosis in the case of muscularis propria infiltration or beyond, irrespective of the dimensions or grading. From these findings, size, grading, and gastric wall infiltration seem to be the most relevant factors in management staff making choices and prognoses of type 3 g-NET patients. We produced a hypothetical flowchart for a standardized approach to these rare diseases.

CONCLUSION

Further prospective analyses are needed to validate the prognostic impact of the use of size, grading, and gastric wall infiltration as prognostic factors in the management of type 3 g-NETs.

Gastric neuroendocrine neoplasms: a primer for radiologists

Gastric neuroendocrine neoplasms are uncommon tumors with variable differentiation and malignant potential. Three main subtypes are recognized: type 1, related to autoimmune atrophic gastritis; type 2, associated with Zollinger-Ellison and MEN1 syndrome; and type 3, sporadic. Although endoscopy alone is often sufficient for diagnosis and management of small, indolent, multifocal type 1 tumors, imaging is essential for evaluation of larger, high-grade, and type 2 and 3 neoplasms. Hypervascular intraluminal gastric masses are typically seen on CT/MRI, with associated perigastric lymphadenopathy and liver metastases in advanced cases. Somatostatin receptor nuclear imaging (such as Ga-68-DOTATATE PET/CT) may also be used for staging and assessing candidacy for peptide receptor radionuclide therapy. Radiotracer uptake is more likely in well-differentiated, lower-grade tumors, and less likely in poorly differentiated tumors, for which F-18-FDG-PET/CT may have additional value. Understanding disease pathophysiology and evolving histologic classifications is particularly useful for radiologists, as these influence tumor behavior, preferred imaging, therapy options, and patient prognosis.

Gastric neuroendocrine neoplasms: A review

Gastric neuroendocrine neoplasms (g-NENs) or neuroendocrine tumors are generally slow-growing tumors with increasing incidence. They arise from enterochromaffin like cells and are divided into four types according to clinical characteristic features. Type 1 and 2 are gastrin dependent, whereas type 3 and 4 are sporadic. The reason for hypergastrinemia is atrophic gastritis in type 1, and gastrin releasing tumor (gastrinoma) in type 2 g-NEN. The diagnosis of g-NENs needs histopathological investigation taken by upper gastrointestinal endoscopy. g-NENs are positively stained with chomogranin A and synaptophysin. Grading is made with mitotic index and ki-67 proliferation index on histopathological analysis. It is crucial to discriminate between types of g-NENs, because the management, treatment and prognosis differ significantly between subtypes. Treatment options for g-NENs include endoscopic resection, surgical resection with or without antrectomy, medical treatment with somatostatin analogues, netazepide or chemotherapy regimens. Follow-up without excision is another option in appropriate cases. The prognosis of type 1 and 2 g-NENs are good, whereas the prognosis of type 3 and 4 g-NENs are close to the prognosis of gastric adenocancer.

Management of Other Gastric and Duodenal Neuroendocrine Tumors

Gastric and duodenal neuroendocrine tumors (NETs) are increasing in incidence as a result of increased detection and awareness of neuroendocrine tumors as distinct tumor types. The three types of gastric NETs and duodenal NETs have different etiologies and tumor-specific factors, such as grade, location, and hormone-production, and the clinical settings influence management. Options for treatment include removal by local endoscopic resection and surgical resection. Medical therapy is used to treat the inciting condition or as systemic therapy in advanced disease. Although the overall prognosis for most is good, higher grade tumors behave aggressively and have reduced survival.

Multiple endocrine neoplasia type 1 (MEN-1) and neuroendocrine neoplasms (NENs)

Neuroendocrine neoplasms (NENs) are relatively rare neoplasms with 6.4-times increasing age-adjusted annual incidence during the last four decades. NENs arise from neuroendocrine cells, which release hormones in response to neuronal stimuli and they are distributed into organs and tissues. The presentation and biological behaviour of the NENs are highly heterogeneous, depending on the organ. The increased incidence is mainly due to increased awareness and improved detection methods both in the majority of sporadic NENs (non-inherited), but also the inherited groups of neoplasms appearing in at least ten genetic syndromes. The most important one is multiple endocrine neoplasia type 1 (MEN-1), caused by mutations in the tumour suppressor gene MEN1. MEN-1 has been associated with different tumour manifestations of NENs e.g. pancreas, gastrointestinal tract, lungs, thymus and pituitary. Pancreatic NENs tend to be less aggressive when arising in the setting of MEN-1 compared to sporadic pancreatic NENs. There have been very important improvements over the past years in both genotyping, genetic counselling and family screening, introduction and validation of various relevant biomarkers, as well as newer imaging modalities. Alongside this development, both medical, surgical and radionuclide treatments have also advanced and improved morbidity, quality of life and mortality in many of these patients. Despite this progress, there is still space for improving insight into the genetic and epigenetic factors in relation to the biological mechanisms determining NENs as part of MEN-1. This review gives a comprehensive update of current evidence for co-occurrence, diagnosis and treatment of MEN-1 and neuroendocrine neoplasms and highlight the important progress now finding its way to international guidelines in order to improve the global management of these patients.

Three Cases of Diffuse, Intense Stomach Uptake on DOTATATE PET

Incidental tracer uptake on DOTATATE PET is increasingly encountered in clinical practice. We describe 3 patients with suspected or known neuroendocrine tumor who were found to have diffuse and intense stomach uptake on DOTATATE PET. All patients underwent esophagogastroduodenoscopy and/or endoscopic ultrasound; the cause of the stomach uptake was attributed to proton-pump inhibitor use, chronic gastritis, and gastrinoma, respectively. These 3 cases highlight that diffuse and intense stomach DOTATATE uptake can be a benign finding probably attributed to proton-pump inhibitor use, chronic gastritis, or gastrinoma.

The future: diagnostic and imaging advances in MEN1 therapeutic approaches and management strategies

Prospective randomized data are lacking, but current clinical expert guidelines recommend annual screening examinations, including laboratory assessments and various imaging modalities (e.g. CT, MRI, scintigraphy and EUS) for patients with multiple endocrine neoplasia type 1 (MEN1). Routine screening is proposed to detect and localize neuroendocrine manifestations as early as possible. The goal is timely intervention to improve quality of life and to increase life expectancy by preventing the development of life-threatening hormonal syndromes and/or metastatic disease. In recent years, some studies compared different and new imaging methods regarding their sensitivity and utility in MEN1 patients. This present article reviews the proposed diagnostic tools for MEN1 screening as well as potential future perspectives.

Preclinical evaluation of PAC1 targeting with radiolabeled Maxadilan

There is an ongoing search for new tracers to optimize imaging of beta cell-derived tumors (insulinomas). The PAC1 receptor, expressed by insulinomas, can be used for targeting of these tumors. Here, we investigated whether radiolabeled maxadilan could be used for insulinoma imaging. Maxadilan was C- or N-terminally conjugated with DTPA (termed maxadilan-DPTA or DTPA-maxadilan respectively). BALB/c nude mice bearing subcutaneous INS-1 tumors were injected with either In-111-labeled maxadilan-DTPA or In-111-DTPA-maxadilan. Biodistribution studies were carried out at 1, 2 and 4 hours after injection and SPECT/CT imaging 1 and 4 hours after injection of maxadilan-DTPA-¹¹¹In. Radiolabeling of maxadilan-DTPA (680 MBq/nmol) was more efficient than of DTPA-maxadilan (55 MBq/nmol). Conjugation with DTPA slightly reduced receptor binding affinity in vitro: IC₅₀ values were 3.2, 21.0 and 21.0 nM for maxadilan, ^natIn-DTPA-maxadilan and maxadilan-DTPA-^natIn respectively. Upon i.v. injection maxadilan-DTPA-¹¹¹In accumulated specifically in INS-1 tumors (7.30 ± 1.87%ID/g) and in the pancreas (3.82 ± 0.22%ID/g). INS-1 tumors were clearly visualized by small animal SPECT/CT. In conclusion, this study showed that the high affinity of maxadilan to the PAC1 receptor was maintained after DTPA conjugation. Furthermore, radiolabeled maxadilan-DTPA accumulated specifically in INS-1 tumors and, therefore, may qualify as a useful tracer to image insulinomas.