Advances in the Treatment of Gastroenteropancreatic Neuroendocrine Carcinomas: Are we Moving Forward?

Abstract

Poorly differentiated gastroenteropancreatic neuroendocrine carcinomas are aggressive neoplasms of challenging clinical management. A small proportion of patients with early-stage disease may achieve long-term survival, but the majority of patients present with rapidly lethal metastatic disease. Current standard of care still follows the treatment paradigm of small cell lung cancer, a far more common G3 neuroendocrine neoplasm, although emerging molecular and clinical data increasingly question this approach. In this article, we will briefly summarize epidemiology and prognosis of gastroenteropancreatic neuroendocrine carcinomas to emphasize the very low incidence, aggressive nature, and orphan status of this tumor entity. We will also discuss the current pathological classification and its limitations, as well as recent data on their differential biological background compared with small cell lung cancer, and its potential implications for patients care. Then, we will review the standard of care of systemic therapy, basically focused on platinum-based cytotoxic chemotherapy, including some recent randomized trials providing evidence regarding efficacy of irinotecan vs etoposide platinum doublets. Finally, we will present a comprehensive overview of novel therapeutic strategies in current clinical development, including recently reported data on immunotherapy, tumor-agnostic therapies (microsatellite instability, high tumor mutational burden, NTRK and RET gene fusions, BRAF or KRAS inhibitors), and additional treatment strategies targeting other tumor vulnerabilities (ie, Notch pathway, novel targets for radioligand therapy), and provide some insights regarding unmet needs and future perspectives to improve patient's care and prognosis.

Keywords: G3; gastroenteropancreatic; neuroendocrine carcinomas; therapy.

Graphical Abstract

Figure 1.

Common genomic alterations in GEP NECs and G3 NETs. Bar plots depict the frequency of samples harboring any genomic alteration (point mutations, copy number gains or losses, amplifications or deletions) for the most frequently mutated genes in small cell NECs, large cell NECs, and G3 NETs of GEP origin (5). G3 NET, grade 3 neuroendocrine tumor; GEP: gastroenteropancreatic; NEC: neuroendocrine carcinoma.