Interim PET/CT scans predict which NET patients will benefit most from peptide receptor radionuclide therapy
Changes in whole tumor volume and total receptor expression on interim 68Ga-DOTA-TOC PET/CT after 2 PRRT cycles significantly predicted progression-free survival in 24 NET patients (HR 3.3-3.9).
Quick Facts
What This Study Found
High ΔWTV (≥-10%): HR 3.053 (p=0.049); high ΔTRE (≥-21%): HR 3.567 (p=0.028) for shorter PFS. Both remained significant in multivariate analysis adjusted for WHO grade (HR 3.345 and 3.894). 66.7% of patients experienced progression.
Key Numbers
How They Did This
Retrospective analysis of 24 NET patients with basal and interim (after 2 PRRT cycles) 68Ga-DOTA-TOC PET/CT. Kaplan-Meier survival analysis, log-rank tests, and Cox proportional hazards regression.
Why This Research Matters
PRRT is expensive and involves radiation exposure. Early identification of non-responders after 2 cycles could guide decisions about continuing PRRT versus switching to alternative therapies, improving both outcomes and resource utilization.
The Bigger Picture
Precision medicine in PRRT: rather than treating all patients the same, interim imaging can personalize treatment by identifying responders early. This approach could optimize outcomes while reducing unnecessary radiation in non-responders.
What This Study Doesn't Tell Us
Small sample (n=24). Retrospective single-center design. Cut-off thresholds need prospective validation. PFS used as endpoint rather than overall survival.
Questions This Raises
- ?Should non-responders identified at interim stop PRRT or switch to combination therapy?
- ?Can these PET parameters be standardized across institutions?
- ?Would adding blood-based biomarkers improve predictive accuracy?
Trust & Context
- Key Stat:
- HR 3.9 for poor responders Patients with <21% reduction in total receptor expression on interim PET had nearly 4x higher risk of disease progression during PRRT
- Evidence Grade:
- Small retrospective study with appropriate statistical methodology. Hypothesis-generating; needs prospective validation.
- Study Age:
- Published in 2025.
- Original Title:
- Prognostic value of interim [68Ga]Ga-DOTA-TOC PET/CT in patients with neuroendocrine tumour who underwent peptide receptor radionuclide therapy.
- Published In:
- European radiology, 35(5), 2559-2568 (2025)
- Authors:
- Shin, Eonwoo, Kim, Yong-Il(2), Yoo, Changhoon(2), Shin, Yeokyeong, Ryoo, Baek-Yeol, Lee, Dong Yun, Ryu, Jin-Sook
- Database ID:
- RPEP-13581
Evidence Hierarchy
Frequently Asked Questions
What is interim PET/CT in PRRT?
It is a scan performed after 2 of the typical 4 treatment cycles of PRRT. By comparing tumor size and receptor expression with the pre-treatment scan, doctors can identify patients who are responding to treatment versus those who are not—potentially allowing earlier treatment adjustments.
Why is early response assessment important?
PRRT involves radioactive peptides that expose the body to radiation. If a patient is not responding after 2 cycles, continuing treatment provides radiation exposure without benefit. Early identification of non-responders allows switching to alternative therapies sooner.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-13581APA
Shin, Eonwoo; Kim, Yong-Il; Yoo, Changhoon; Shin, Yeokyeong; Ryoo, Baek-Yeol; Lee, Dong Yun; Ryu, Jin-Sook. (2025). Prognostic value of interim [68Ga]Ga-DOTA-TOC PET/CT in patients with neuroendocrine tumour who underwent peptide receptor radionuclide therapy.. European radiology, 35(5), 2559-2568. https://doi.org/10.1007/s00330-024-11116-5
MLA
Shin, Eonwoo, et al. "Prognostic value of interim [68Ga]Ga-DOTA-TOC PET/CT in patients with neuroendocrine tumour who underwent peptide receptor radionuclide therapy.." European radiology, 2025. https://doi.org/10.1007/s00330-024-11116-5
RethinkPeptides
RethinkPeptides Research Database. "Prognostic value of interim [68Ga]Ga-DOTA-TOC PET/CT in pati..." RPEP-13581. Retrieved from https://rethinkpeptides.com/research/shin-2025-prognostic-value-of-interim
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Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.