Evaluation of survival outcomes in patients with sporadic, advanced, unresectable well-differentiated pancreatic neuroendocrine tumors treated initially with octreotide LAR and subsequent therapeutical approaches on relapse. A real-world data set

Abstract

Introduction. Somatostatin analogs (SSA) are widely used in the treatment of patients with well-differentiated neuroendocrine tumors (NET). There are limited reports about the role of octreotide LAR in first-line therapy of advanced pancreatic NET (pan-NET). This study aimed to evaluate the antiproliferative effect of octreotide LAR in patients with sporadic, advanced, unresectable pan-NET, based on progression-free survival (PFS). Material and methods. This was a retrospective analysis of 374 patients with pan-NET; 41 treated subjects were included. The primary endpoint was PFS defined as the time to disease progression (Response Evaluation Criteria in Solid Tumors: RECIST). Univariate and multivariate analyses were used to identify predictors of PFS. Secondary endpoints included overall survival (OS) and second-line therapies after progression. Results. There were 13 (32%) patients with G1 pan-NET and 28 (68%) with pan-NET G2, 21 female and 20 male, with mean age 55.4 (range 29–87). Median PFS was 9.0 months (95% CI 4.7–24.0). Subgroup analysis revealed that G1 and no-bulky liver disease (< 25% liver volume) were associated with significantly longer PFS. Univariate analysis confirmed a correlation between G1 [0.34 hazard rate (HR) of progression or death (95% CI 0.16–0.72)] and no-bulky liver disease HR = 0.31 (95% CI 0.13–0.71). Multivariable analysis demonstrated that only functional (secretory) pan-NET was associated as an independent factor with shorter PFS HR = 2.97 (95% CI 1.0–8.74). Median OS was 105.4 months (95% CI 40.0–172.0). After relapse following initial systemic therapy, the second line was used in 34 subjects, 3rd line in 18th, and 4th line in 9 subjects. Conclusions. Octreotide LAR shows moderate antiproliferative activity in pan-NET. Prolonged PFS may be associated with G1 and low-volume metastatic liver disease. In patients with progressive disease, various treatment options were used, which resulted in median OS of 105.4 months.