Clinical outcomes of patients with G1/G2 neuroendocrine tumors arising from foregut or hindgut treated with somatostatin analogs: a retrospective study

Neuroendocrine tumors (NET) are rare tumors for which somatostatin analogs (SSA) are used not only for symptom control due to a functioning tumor, but also for the disease control of unresectable NET. The efficacy of SSA for midgut NET has been verified by previous studies, but insufficient evidence exists for SSA treatment of NET in the foregut and hindgut (F/H-NET). The aim of this retrospective study was to evaluate the efficacy of SSA for unresectable F/H-NET. Patients with unresectable F/H-NET treated with SSA between February 2011 and August 2017 at our hospital were retrospectively reviewed. Parameters of efficacy were progression-free survival (PFS), overall survival, objective response rate (ORR), and adverse events. Twelve cases with unresectable F/H-NET were extracted from our database. With a median follow-up time of 25.9 months, the median PFS was 13.6 months. Two- and 3-year survival rates were 87.5 and 62.5%, respectively. The ORR was 8.3%, and the disease control rate was 75%. Serious adverse events were not observed. Subgroup analysis, including G1/G2, and hepatic tumor load, which is the volume of NET liver metastases, did not reveal a difference in PFS. The efficacy and safety of SSA for F/H-NET seemed similar to that found in the PROMID study, highlighting its relevance for the treatment of this disease.