Somatostatin Analogs for Pancreatic Neuroendocrine Tumors: Any Benefit When Ki‐67 Is ≥10%?

BackgroundLong‐acting somatostatin analogs (SSAs) are the primary first‐line treatment of well‐differentiated advanced gastroenteropancreatic neuroendocrine tumors (NETs), but data about their efficacy in pancreatic NETs (panNETs) with Ki‐67 ≥10% are still limited.Materials and MethodsTo assess the clinical outcomes of advanced, nonfunctioning, well‐differentiated panNETs with Ki‐67 ≥10% receiving first‐line long‐acting SSAs in a real‐world setting, we carried out a retrospective, multicenter study including patients treated between 2014–2018 across 10 centers of the NET CONNECT Network. The primary endpoints were time to next treatment (TNT) and progression‐free survival (PFS), whereas overall survival (OS) and treatment safety were secondary endpoints.ResultsA total of 73 patients were included (68 grade [G]2, 5 G3), with liver metastases in 61 cases (84%). After a median follow‐up of 36.4 months (range, 6–173), the median TNT and PFS were 14.2 months (95% confidence interval [CI], 11.6–16.2) and 11.9 months (95% CI, 8.6–14.1) respectively. No statistically significant difference was observed according to the somatostatin analog used (octreotide vs. lanreotide), whereas increased tumor grade (hazard ratio [HR], 4.4; 95% CI, 1.2–16.6; p = .04) and hepatic tumor load (HR, 2; 95% CI, 1–4; p = .03) were independently associated with shortened PFS. The median OS recorded was 86 months (95% CI, 56.8–86 months), with poor outcomes observed when the hepatic tumor burden was >25% (HR, 3.4; 95% CI, 1.2–10; p = .01). Treatment‐related adverse events were reported in 14 patients, most frequently diarrhea.ConclusionSSAs exert antiproliferative activity in panNETs with Ki‐67 ≥10%, particularly in G2 tumors, as well as when hepatic tumor load is ≤25%.Implications for PracticeThe results of the study call into question the antiproliferative activity of somatostatin analogs (SSAs) in pancreatic neuroendocrine tumors with Ki‐67 ≥10%. Patients with grade 2 tumors and with hepatic tumor load ≤25% appear to derive higher benefit from SSAs. Prospective studies are needed to validate these results to optimize tailored therapeutic strategies for this specific patient population.