Treatment and long term safety outcomes of Peptide Receptor Radionuclide Therapy for metastatic neuroendocrine tumours: an Asian experience.

Peptide-receptor radionuclide therapy (PRRT) is a targeted molecular therapy used to treat neuroendocrine tumours (NET). It has been shown to be effective and well-tolerated in patients with metastatic neuroendocrine tumours in several centres in United States (US), Europe and Australia. Tolerability and efficacy data emerging from Asian centres remain few. Epidemiological evidence suggests that there are differences in neuroendocrine neoplasms between the population groups. We aim to describe the treatment and safety outcomes of PRRT in the Asian population. Methods One hundred and seven (107) patients with metastatic neuroendocrine tumour who had undergone PRRT treatment from January 2012 to March 2019 were included in this retrospective study. The response rates using RECIST1.1 and qualitative analysis were examined. The overall and progression free survival curves were also evaluated. Results The median progression free survival was 49 months. Response assessment after completion of treatment showed that 33(37.9%) of 87 patients had partial or complete response. Subgroup analysis comparing high- and low-grade NET showed that there was a significant difference in the time to progression curves. Comparison of the number of cycles and progression free and overall survival also showed a significant difference. Ten patients (9%) had grade 3 or more haematological toxicities. Four patients (4%) had grade 3/4 hepatobiliary toxicities, although the presence of extensive liver metastases was a confounding factor. None of the patients had grade 3/4 acute kidney injury. Conclusion Our results show that PRRT is safe and effective in the treatment of metastatic neuroendocrine tumour in the Asian population. There was a significant difference in the progression free survival curves between low-grade and high-grade NET, and in the progression free and overall survival comparing the number of cycles received.