Outcomes of peptide receptor radionuclide therapy after progression following hepatic cytoreductive operation for neuroendocrine tumors.
PRRT is a treatment option for patients with inoperable progression after hepatic cytoreduction, but the study does not support claims of its superiority over other therapies.
Where it sits
this study against the rest of the octreotide corpusSummary and findings
This study measured progression-free survival (PFS) and overall survival (OS) in patients with neuroendocrine tumors who received peptide receptor radionuclide therapy (PRRT) after hepatic cytoreductive operations. Seventy-five patients were included, with a median PFS after cytoreduction of 44 months and a median OS of 97 months. The findings suggest that PRRT is a treatment option but do not confirm previous claims of its superiority.
Abstract
<h4>Background</h4>Peptide receptor radionuclide therapy (PRRT) attaches radioactive lutetium-177 to octreotide to treat inoperable metastatic gastroenteropancreatic neuroendocrine tumors (GEPNETs). PRRT has been available in Europe for decades, receiving FDA approval in 2018 after the NETTER-1 trial, which showed improved progression free survival (PFS), but not overall survival (OS). However, Borbon et al. recently showed an OS of 156 months in patients receiving PRRT for progression after hepatic cytoreduction operations (HCO) compared to 106 months for other treatments, implying PRRT is superior. This finding needs confirmation from another major GEPNET center.<h4>Methods</h4>Our database was reviewed for patients who received PRRT for inoperable progression following HCO. Data collected included primary tumor type, grade, date of operation, date of inoperable progression, date of progression after PRRT, and status at last follow up. PFS and OS were calculated using Kaplan and Meier analyses and compared between subgroups.<h4>Results</h4>Seventy-five patients were identified. There were 52 patients with small bowel and 23 with pancreatic primaries. Median PFS after cytoreduction was 44 months. Median PFS after PRRT was 32 months. Median OS was 97 months. There weren't significant differences in PFS or OS based on primary type or grade. On multivariate Cox regression, neither primary site nor PRRT timing independently predicted OS.<h4>Conclusions</h4>Our results do not confirm those of Borbon et al. Our survival after PRRT was closer to what they found with other therapies. We conclude that PRRT is a treatment option for patients with inoperable progression after HCO, but not necessarily superior.
Background
This paper addresses the efficacy of peptide receptor radionuclide therapy (PRRT) in patients with inoperable metastatic gastroenteropancreatic neuroendocrine tumors (GEPNETs) following hepatic cytoreductive operations (HCO). Prior studies, notably the NETTER-1 trial, indicated improved progression-free survival (PFS) with PRRT but did not demonstrate a significant increase in overall survival (OS). The findings from Borbon et al. suggested an OS of 156 months with PRRT, which prompted the need for further investigation in a different cohort.
Methods
The study reviewed a database of patients who received PRRT for inoperable progression after HCO. A total of 75 patients were included, with data collected on primary tumor type, grade, and survival metrics. PFS and OS were calculated using Kaplan and Meier analyses, with comparisons made between subgroups.
Results
The median PFS after cytoreduction was 44 months, and the median PFS after PRRT was 32 months. The median OS for the cohort was reported as 97 months. No significant differences in PFS or OS were found based on primary tumor type or grade. Additionally, multivariate Cox regression analysis indicated that neither primary site nor timing of PRRT independently predicted OS.
Interpretation
The results of this study do not support the previous claims of superior OS with PRRT as suggested by Borbon et al. The median OS of 97 months is closer to what was observed with other therapies, indicating that while PRRT may be a viable option, it may not offer a significant advantage. Limitations such as the study's retrospective nature and potential confounding factors should be considered when interpreting the findings.
Key findings
- Median PFS after cytoreduction was 44 months.
- Median PFS after PRRT was 32 months.
- Median OS was 97 months.
- There weren't significant differences in PFS or OS based on primary type or grade.
- On multivariate Cox regression, neither primary site nor PRRT timing independently predicted OS.
Limitations
- Retrospective study design.
- Small sample size of n=75.
- No significant differences in PFS or OS based on tumor type or grade.
- Multivariate analysis did not find predictors for OS.