Role of Resection of the Primary Pancreatic Neuroendocrine Tumour Only in Patients with Unresectable Metastatic Liver Disease: A Systematic Review.

Background: Surgery remains the only curative option for pancreatic neuroendocrine tumours (PNETs), but its indication is limited by metastatic disease in most patients. Indication for removing the primary lesion only in the setting of unresectable liver disease is controversial. The present systematic review aims at determining the potential bene- fits (survival, progression-free survival) or harms (morbidity, mortality) of surgical resection of the primary lesion only in patients with PNETs and unresectable metastases. Meth ods: Medline was queried for studies reporting the outcome of PNET patients with unresectable liver metastases whenever there was an explicit comparison between resection of the primary lesion only ('active treatment') and no resection ('non-active treatment'). The primary outcome was survival; possible secondary outcomes were progression-free survival, treatment-related mortality and morbidity, and relief of symptoms. Results: Only 3 cohort studies found were eligible and analysed; no meta-analysis could be performed. The number of patients undergoing 'active treatment' varied from 16 to 20, with a percentage ranging from 17 to 39\% of cohorts. Survival was longer in patients who received 'active treatment' in 2 studies, and the 5-year survival rate also seemed higher, without significant complications. Discussion: Available data suggest a possible benefit of resection of the primary lesion only in this setting. However, a bias towards a more aggressive surgical approach in patients with a better performance status or less advanced disease seems likely, and no conclusion can be drawn except for the need of randomised trials. We calculated that such a trial would require at least 118 patients per arm.