Real-world outcomes in patients with gastroenteropancreatic neuroendocrine tumors receiving somatostatin analogue: Data from a public hospital in Brazil.

Abstract

650 Background: Neuroendocrine tumors are rare malignant neoplasms derived from endocrine cells and known for their heterogeneous behavior and histopathological characteristics; however, largely associated with a favorable clinical outcome. Somatostatin analogues (SSA) were initially used to control the symptoms of secretory neuroendocrine tumors, and later, they were considered effective as a first-line systemic treatment in unresectable or metastatic neuroendocrine tumors of the gastroenteropancreatic tract (NET-GEP). Randomized clinical trials are performed in controlled environments, with strict inclusion and exclusion criteria, and therefore, real-world studies can add to efficacy and safety data in the general population. Methods: To evaluate, in the real world scenario of a tertiary hospital of the public health system, the efficacy and toxicities of first-line treatment with somatostatin analogue in patients diagnosed with unresectable or metastatic NET-GEP, to find real-world progression free survival (rwPFS) and real-world overall survival (rwOS), in addition to the toxicity profile in our population and possible subgroups that benefit from first-line treatment, through the analysis of variables. Results: 29 patients met the study inclusion criteria, which were diagnosed in the period from 2009 to 2017. The median wrSLP and wrSG were 4.4 (95% CI 3.2 – 5.6) and 8.2 years (CI 95% 6.2 – 10.2), respectively. In an adjusted analysis of rwSLP, the HR for patients with hindgut tumors compared to midgut tumors was 4.41 with p 0.05, indicating that these patients had a 4x increased risk for disease progression (p 0 .05). In the adjusted analysis of wrSG, a trend towards a more favorable evolution was observed in the group of patients with well-differentiated tumors, with p 0.05. Assessment of toxicities revealed grade 2 and grade 3 adverse events in 34.48% of patients. Abdominal pain was the most incident toxicity, occurring in 17.24%, followed by headache (13.79%) and diarrhea (10.34%). Conclusions: Treatment with SSA was effective in our sample, with rwPFS and rwOS data above those found in randomized clinical trials. The toxicities were easily manageable and caused no documented harm to patients.