Clinical efficacy of first and second series of peptide receptor radionuclide therapy in patients with neuroendocrine neoplasm: a cohort study

Abstract

Objectives

Peptide receptor radionuclide therapy (PRRT) is an established treatment for metastatic neuroendocrine neoplasms (NEN). However, only limited data exists for the effect of multiple series of PRRT. The aim of this study was to investigate PFS and OS inNEN patients treated with multiple series of PRRT conforming to the ENETS treatment protocol.

Methods

We included all patients with gastrointestinal (GI), pancreatic and bronchopulmonary (BP) NEN treated with PRRT from 2008 to 2018. We used Kaplan-Meier estimation to evaluate PFS and OS with subgroup analysis of primary tumor, Ki67-index, type of radioisotope and number of PRRT series.

Results

133 patients (female/male 61/72) were included, median age 70 (interquartile range 64–76) years. GI-NEN comprised 62%, pancreatic 23% and BP 11%. Median Ki67-index was 5%. After first PRRTG1- and G2-tumors had PFS of 25 and 22 months, compared to 11 months in G3-NENs (p < .05) and PFS was longer in G1/G2 GI-NENs than BP-NEN (30vs. 12 months, p < .05). After retreatment with a second series of PRRT, the overall PFS (G1–G3) was 19 months, with G1- and G2-tumors having the highest PFS of 19 and 22 months, respectively. Overall, the GI and BP tumors had an OS of 54 and 51 months.

Conclusions

PRRT is an effective therapy with long-term PFS and OS, especially in G1 and G2 NENs, and with better prognosis in GI-NEN compared with BP-NENs. OS and PFS was shorter after the second series of PRRT compared with the first, however results were still encouraging.

Keywords:

• Neuroendocrine
• gastropancreatic tumors
• bronchopulmonary tumors
• peptide receptor radionuclide therapy
• first and second series

Ethical approval

The study was approved by the local ethics committee of Central Region Midt-Jutland and according to national regulations the need for consent was waived (656236).

Author contributions

H. Grønbaek, G. Dam and M. D. Zacho conceived the study. M. D. Zacho extracted the data and performed data analysis in collaboration with G. Dam, H. Grønbaek and S. M. D. Baunwall. P. Iversen, G. E. Villadsen and A. K. Arveschoug evaluated treatment responses. All authors participated in drafting the manuscript and all authors approved the final version.

Disclosure statement

H. Grønbaek has received research grants from Abbvie, Intercept and NOVO Nordisk Foundation, and is on advisory board at Ipsen and speaker for Norgine. The other authors have no conflicts of interest.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.