Adding Chemotherapy to Peptide Radiation Therapy Doubles Response Rate in Aggressive Neuroendocrine Tumors | Research

The takeaway

Combining PRRT with capecitabine/temozolomide radiosensitization achieved 90% disease control rate and 26-month median PFS in high-Ki67 neuroendocrine tumors, compared to 60% and 12 months with PRRT alone.

90% vs 60%
disease control rate with PRRT+CAP/TEM vs PRRT alone in aggressive NETs

What the researchers found

PRRT + CAP/TEM achieved 90% disease control rate (70% partial response) vs 60% (20% PR) for PRRT alone, with 26 vs 12 months median PFS, in high-Ki67 neuroendocrine tumors.

Why it matters

Aggressive neuroendocrine tumors have limited treatment options. This study suggests adding oral chemotherapy to PRRT can dramatically improve outcomes for patients with higher-proliferation tumors without increasing side effects.

The numbers in context

20 patients with histologically confirmed gastroenteropancreatic neuroendocrine tumors with higher proliferation rates and somatostatin receptor positivity.

How the study worked

Retrospective cohort study of 20 patients with GEP-NET (Ki67 15-55%), comparing PRRT alone (n=10) to PRRT + capecitabine/temozolomide (n=10) for at least 2 cycles, with RECIST response, PFS, DSS, metabolic tumor volume, and chromogranin A endpoints.

Who was studied

Patients with highly proliferative somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors

What this study cannot tell us

Small retrospective study (20 patients); not randomized; potential selection bias; short follow-up for some patients; Ki67 15-55% represents a heterogeneous group; single-center experience.

How to read the evidence

Preliminary evidence from a small retrospective comparison. The dramatic effect size is compelling but requires prospective randomized validation.

When this study was published

Published in 2024, supporting the growing trend of combining PRRT with radiosensitizing chemotherapy for aggressive NETs.

The bigger picture

PRRT has been a game-changer for indolent NETs, and this combination approach may extend its benefits to the more aggressive tumors where treatment options are most needed — potentially reshaping the treatment landscape for intermediate-grade neuroendocrine cancers.

Questions still open

Will randomized prospective trials confirm these dramatic benefits?
What is the optimal number of PRRT + CAP/TEM cycles for maximum benefit?
Are there biomarkers that predict which high-Ki67 patients will respond best to this combination?

Common questions

Why add chemotherapy to peptide radiation therapy for neuroendocrine tumors?

PRRT works well for slow-growing tumors but is less effective for more aggressive ones. Adding capecitabine/temozolomide makes the cancer cells more sensitive to the radiation carried by the peptide, dramatically improving response rates from 60% to 90% without increasing side effects.

Is this combination treatment available now?

Yes, both PRRT and CAP/TEM are individually approved treatments. This combination can be discussed with your oncologist, though the evidence supporting it is still emerging and prospective clinical trials are needed.

Read the original research

Radiosensitizing Favors Response to Peptide Receptor Radionuclide Therapy in Patients With Highly Proliferative Neuroendocrine Malignancies: Preliminary Evidence From a Clinical Pilot Study.

Clinical nuclear medicine, 49(3), 207-214

View on PubMed ↗Publisher’s paper ↗

Citation

Trautwein, Nils Florian; Hinterleitner, Clemens; Kiefer, Lena Sophie; Singer, Stephan; Mattern, Sven; Schwenck, Johannes; Reischl, Gerald; Sipos, Bence; Lauer, Ulrich M; Dittmann, Helmut; Zender, Lars; la Fougère, Christian; Hinterleitner, Martina. (2024). Radiosensitizing Favors Response to Peptide Receptor Radionuclide Therapy in Patients With Highly Proliferative Neuroendocrine Malignancies: Preliminary Evidence From a Clinical Pilot Study.. Clinical nuclear medicine, 49(3), 207-214. https://doi.org/10.1097/RLU.0000000000005006