Clinical bottom line
For patients with localized pancreatic neuroendocrine tumors (PNETs), current evidence suggests that both surgical resection and active surveillance are viable management strategies, particularly for small, nonfunctioning tumors. Surgical resection remains the standard for symptomatic or larger tumors due to its potential for cure, but emerging data indicate that carefully selected patients with small, asymptomatic lesions may be safely monitored without immediate surgery. This nuanced approach balances surgical risks against tumor progression risk and warrants individualized decision-making informed by tumor characteristics and patient factors.
What the evidence shows
Recent comparative studies have evaluated outcomes of surgical resection versus active surveillance in localized PNETs. Salimgereeva et al. (2026) conducted a survival analysis comparing these approaches and found no significant difference in overall survival between patients undergoing surgery and those managed with surveillance for small, localized tumors. This study supports a conservative approach in select cases, especially for tumors less than 2 cm in diameter.
Similarly, Marx et al. (2023) reported on a single-center observational cohort of patients with nonfunctioning PNETs initially managed by surveillance or surgery. Their findings indicated that initial surveillance did not compromise long-term outcomes for tumors under 2 cm, with low rates of progression and delayed surgery feasible upon tumor growth or symptom development.
Endoscopic ultrasound (EUS) has emerged as a valuable tool in the management of PNETs, aiding in diagnosis, staging, and surveillance. Bruni et al. (2026) highlighted the role of EUS not only in tumor characterization but also in guiding treatment decisions, including the feasibility of minimally invasive interventions and monitoring during surveillance.
Older surgical series and reviews (Boukerrouche et al., 2020; Wu et al., 2014) emphasize that surgical resection offers definitive treatment with curative intent, especially for functioning tumors or those with higher malignant potential. However, these sources also acknowledge the morbidity associated with pancreatic surgery, underscoring the importance of patient selection.
Khajeh et al. (2025) provided a recent comparative analysis reinforcing that while surgery remains the mainstay for symptomatic or larger tumors, non-surgical management can be appropriate for small, asymptomatic lesions, with careful follow-up protocols.
Caveats and uncertainty
Most available data derive from retrospective cohorts or observational studies, with limited randomized controlled trials directly comparing surgery and surveillance. Selection bias is a concern, as patients chosen for surveillance often have smaller, less aggressive tumors and better baseline health.
Tumor heterogeneity complicates decision-making; factors such as tumor grade, Ki-67 index, and functional status influence prognosis but are not uniformly reported or standardized across studies. The optimal surveillance interval and imaging modality remain areas of active investigation.
Long-term outcomes beyond 5-10 years are not well characterized, raising uncertainty about late progression or metastasis in patients initially managed conservatively. Additionally, the psychological impact of surveillance and patient preferences must be considered.
EUS expertise and availability may limit the generalizability of surveillance strategies, as accurate tumor assessment is critical to safely deferring surgery.
How this may change practice
This evolving evidence encourages a more personalized approach to localized PNETs, integrating tumor size, functionality, patient comorbidities, and preferences into management decisions. For small (<2 cm), nonfunctioning tumors without high-risk features, active surveillance with periodic imaging and EUS may be a reasonable alternative to immediate surgery, potentially sparing patients from surgical morbidity.
Surgeons and multidisciplinary teams should incorporate advanced imaging modalities and tumor biology markers to stratify risk and tailor follow-up protocols. Shared decision-making is paramount, with clear communication about the benefits and risks of each approach.
Centers with expertise in pancreatic neuroendocrine tumors and access to high-quality EUS and multidisciplinary care are best positioned to implement surveillance strategies safely.