Long-term disease free survival of gastric mixed adenoneuroendocrine carcinoma treated with multimodality therapy: A case report

Neoadjuvant chemotherapy improves the survival of patients with neuroendocrine carcinoma and mixed adenoneuroendocrine carcinoma of the stomach

PURPOSE

The impact of neoadjuvant chemotherapy (NAC) on patients with neuroendocrine carcinoma (NEC) and mixed adenoneuroendocrine carcinoma (MANEC) of the stomach is unclear. The aim of this retrospective study was to evaluate the effects of NAC on patients with these conditions.

METHODS

This study included patients with locally advanced NEC or MANEC of the stomach who underwent gastrectomy. Histologic and prognostic effects of NAC were assessed. The overall survival (OS) rate was used to compare treatment efficacies between NAC patients and surgery-first patients.

RESULTS

Of the 69 patients included in this study, 20 received NAC and 49 underwent surgery first after diagnosis. A total of 13 patients responded to NAC (including 3 with complete remission and 10 with partial remission) and 7 patients acquired stable disease status according to the Response Evaluation Criteria in Solid Tumors version 1.1. One patient (5%) achieved a pathological complete response after NAC. Pathological tumor regression grades 1, 2, 3, 4, and 5 were observed in 1 (5%), 5 (25%), 3 (15%), 10 (50%), and 1 (5%) patient(s) with NAC, respectively. The incidence of postoperative complications was similar in the two groups. Patients in the NAC group demonstrated better OS than did patients in the surgery-first group (P = 0.032). Multivariate analyses showed that NAC, adjuvant chemotherapy, and the clinical N stage were independent factors affecting OS.

CONCLUSION

In patients with locally advanced NEC and MANEC of the stomach, NAC significantly improved OS.

Mixed Neuroendocrine Non-Neuroendocrine Neoplasms: A Systematic Review of a Controversial and Underestimated Diagnosis

Mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs) represent a rare diagnosis of the gastro-entero-pancreatic tract. Evidence from the current literature regarding their epidemiology, biology, and management is of variable quality and conflicting. Based on available data, the MiNEN has an aggressive biological behaviour, mostly driven by its (often high-grade) neuroendocrine component, and a dismal prognosis. In most cases, the non-neuroendocrine component is of adenocarcinoma histology. Due to limitations in diagnostic methods and poor awareness within the scientific community, the incidence of MiNENs may be underestimated. In the absence of data from clinical trials, MiNENs are commonly treated according to the standard of care for pure neuroendocrine carcinomas or adenocarcinomas from the same sites of origin, based on the assumption of a biological similarity to their pure counterparts. However, little is known about the molecular aberrations of MiNENs, and their pathogenesis remains controversial; molecular/genetic studies conducted so far point towards a common monoclonal origin of the two components. In addition, mutations in tumour-associated genes, including TP53, BRAF, and KRAS, and microsatellite instability have emerged as potential drivers of MiNENs. This systematic review (91 full manuscripts or abstracts in English language) summarises the current reported literature on clinical, pathological, survival, and molecular/genetic data on MiNENs.

Pathologic Complete Response After Neoadjuvant Chemoradiation in a Patient with Gastric Neuroendocrine Cancer

Neuroendocrine tumors are about 0.5% of all malignancies. Specifically, for gastrointestinal (GI) malignancies, neuroendocrine tumor incidence is approximately 1%-2% per year. Gastric neuroendocrine neoplasms are rare and consist of various tumor types with differing histomorphology, pathogenesis, and biological behavior. Following surgery, post-operative chemotherapy is generally considered the standard of care. Our case report demonstrates the potential benefit of neoadjuvant concurrent chemoradiotherapy prior to surgery for a malignant gastric neuroendocrine tumor. While radiotherapy has been demonstrated to possibly provide a survival benefit in the treatment of GI neuroendocrine tumors, its use in treatment, particularly neoadjuvantly, needs to be further assessed.

Prognostic Threshold of Neuroendocrine Differentiation in Gastric Carcinoma: a Clinicopathological Study of 945 Cases

Purpose

The significance of neuroendocrine differentiation (NED) in gastric carcinoma (GC) is controversial, leading to ambiguous concepts in traditional classifications. This study aimed to determine the prognostic threshold of meaningful NED in GC and clarify its unclear features in existing classifications.

Materials and Methods

Immunohistochemical staining for synaptophysin, chromogranin A, and neural cell adhesion molecule was performed for 945 GC specimens. Survival analysis was performed using the log-rank test and univariate/multivariate models with percentages of NED (P_NED) and demographic and clinicopathological parameters.

Results

In total, 275 (29.1%) cases were immunoreactive to at least 1 neuroendocrine (NE) marker. GC-NED was more common in the upper third of the stomach. P_NED, and Borrmann's classification and tumor, lymph node, metastasis stages were independent prognostic factors. The cutoff P_NED was 10%, beyond which patients had significantly worse outcomes, although the risk did not increase with higher P_NED. Tumors with ≥10% NED tended to manifest as Borrmann type III lesion with mixed/diffuse morphology and poorer histological differentiation; the NE components in this population mainly grew in insulae/nests, which differed from the predominant growth pattern (glandular/acinar) in GC with <10% NED.

Conclusions

GC with ≥10% NED should be classified as a distinct subtype because of its worse prognosis, and more attention should be paid to the necessity of additional therapeutics for NE components.