Management of small, asymptomatic, non-functioning pancreatic neuroendocrine tumours: follow-up, ablation, or surgery?

Abstract

ing > 4 cm compared with 2% for tumours of 2-3 cm and 1% for those < 2 cm [8]. The growth rate also depends on the size. An endoscopic ultrasound (EUS) study of 226 pNETs in patients with MEN1 syndrome showed an average growth rate of 0.1 mm per year, with no size progression in tumours measuring < 10 mm but progression of 0.44 mm/year in larger tumours [11].Non-functioning sporadic tumours, which do not secrete hormones that cause clinical symptoms, are the most common type of pNETs and the focus of this review. The management of these tumours remains a clinical challenge and dilemma, largely because of uncertainty about their biology and factors related to malignant potential. Pancreatic surgery is complex and carries significant risk for complications including death, but taking a watch-and-wait approach risks development of metastases.There is consensus among experts and guidelines that NF-pNETs < 1 cm can be safely followed up, taking into account their small metastatic potential reported in the literature [5,12]. However, the European Neuroendocrine Tumour Society (ENETS) and North American Neuroendocrine Tumor Society (NANETS) guidelines are somewhat discrepant in their recommendation regarding when surgery should be performed for larger Pancreatic neuroendocrine tumours (pNETs) constitute up to 2% of pancreatic tumours and are detected with increasing frequency [1]. Most are sporadic, but they can develop as part of inherited syndromes, including multiple endocrine neoplasia 1 (MEN1), von Hippel-Lindau syndrome, and tuberous sclerosis [2][3][4]. These lesions are most commonly well-differentiated tumours with no hormonal activity, and their incidence increases with age [5]. The paucity of symptoms arising from their non-secreting nature is the primary reason they usually go undetected until they reach more advanced stages, compared with their functional counterparts. The overall 5-year survival in non-functional (NF)-pNETs is up to 43%, and median survival is 38 months. These survival metrics are much better than in pancreatic adenocarcinoma but still worse than in other gastrointestinal tumours such as colorectal cancer [6,7].Data indicate that the tumour size correlates with malignant potential, which in turn affects survival and mortality [8][9][10]. Bettini et al., using postoperative specimens, found that tumours measuring > 4 cm had significantly higher rates of microvascular invasion (26% vs. 13% for tumours < 2 cm) and of liver (4% vs. 0%) and nodal (20% vs. 13%) metastases [8]. The median antigen

Prediction of disease recurrence in patients after complete pancreatic NET (PanNET) G2 resection

“…Literature reports about PanNET size determining unfavourable prognosis are inconsistent [14]. In the current study, tumour size > 4 cm seems a reasonable cut-off point because it was close to statistical significance.…”

Epidemiology of Neuroendocrine Neoplasms and Results of Their Treatment with [177Lu]Lu-DOTA-TATE or [177Lu]Lu-DOTA-TATE and [90Y]Y-DOTA-TATE—A Six-Year Experience in High-Reference Polish Neuroendocrine Neoplasm Center

“…While the first line of NEN treatment is surgery, besides the observation of asymptomatic and non-functioning tumors, the most up-to-date guidelines advocate for using RLT as a second line of G1 and G2 NEN treatment (or first, in cases of inoperable tumors)-this was previously chemotherapy [4,27]. Another potential treatment option includes local procedures such as endoscopic-ultrasound-guided radiofrequency ablation (EUS-RFA), endoscopic-ultrasound-guided ethanol ablation (EUS-EA), or the administration of radioisotopes directly to the arteries supplying the tumor or its liver metastases [28][29][30][31].…”

Re-treatment with [177Lu]Lu-DOTA-TATE or [177Lu]Lu-DOTA-TATE and [90Y]Y-DOTA-TATE of patients with progressive neuroendocrine neoplasm

“…Surgical removal of the primary lesion and/or metastases is the first choice in the majority of cases. The alternative in small lesions is endoscopic alcoholization [14]. Subsequently, in the presence of somatostatin receptors detected in functional tests (PET/CT with 68 Ga or somatostatin receptor scintigraphy with 99m Tc), chronic treatment with long-acting somatostatin analogues such as octreotide or lanreotide is initiated [15].…”