TANDEM Radiation Therapy Achieves Partial Remission in Rare Parotid Gland Cancer Metastasis | Research

The takeaway

A patient with pancreatic neuroendocrine cancer metastasized to the parotid gland achieved partial remission with TANDEM PRRT using Actinium-225 and Lutetium-177 with somatostatin receptor antagonist DOTA-LM3.

Partial remission after 2 cycles
All metastatic sites responded to TANDEM PRRT after failure of prior conventional treatments

What the researchers found

TANDEM PRRT with Ac-225/Lu-177 labeled DOTA-LM3 (somatostatin receptor antagonist) achieved partial remission in all metastatic sites of a treatment-refractory pancreatic NEN with parotid metastasis.

Why it matters

This demonstrates that when standard PRRT fails, switching to a receptor antagonist-based approach with alpha-emitting radiation can still achieve meaningful tumor control.

The numbers in context

38-year-old woman. Pancreatic NEN with parotid metastasis. Prior DOTATOC PRRT and surgery failed. 2 cycles TANDEM-PRRT (Ac-225 + Lu-177 DOTA-LM3). Partial remission in parotid and liver.

How the study worked

Single case report of a 38-year-old woman with progressive metastatic pancreatic NEN treated with TANDEM PRRT after failure of prior therapies.

Who was studied

One woman with metastatic pancreatic NEN and parotid metastasis

What this study cannot tell us

Single case report — success in one patient does not guarantee broader efficacy. Optimal dosing and long-term outcomes need larger studies.

How to read the evidence

Single case report — lowest evidence level but demonstrates feasibility and efficacy of a novel therapeutic approach in a treatment-resistant setting.

When this study was published

Published in 2025, representing the cutting edge of targeted alpha-beta radionuclide combination therapy.

The bigger picture

TANDEM therapy combining alpha and beta radiation with receptor antagonists represents a new frontier in targeted radionuclide therapy for treatment-resistant neuroendocrine cancers.

Questions still open

Is TANDEM therapy with DOTA-LM3 more effective than sequential alpha-then-beta approaches?
What is the long-term durability of TANDEM PRRT responses?

Common questions

What is TANDEM PRRT?

TANDEM therapy combines two types of targeted radiation in one treatment — alpha particles (from Actinium-225) that destroy cells at very close range, and beta particles (from Lutetium-177) that cover a wider area. Both are attached to peptides that home to cancer cells.

What makes DOTA-LM3 different from standard PRRT?

DOTA-LM3 is a somatostatin receptor antagonist, while standard PRRT agents (like DOTATATE) are agonists. Antagonists bind to more receptor sites on the tumor surface, potentially delivering more radiation to cancer cells.

Read the original research

TANDEM Peptide Receptor Radionuclide Therapy Using [ 225 Ac]Ac-/[ 177 Lu]Lu-DOTA-LM3 in a Patient With Parotid Gland Metastasis From Pancreatic Neuroendocrine Neoplasm.

Clinical nuclear medicine, 50(10), e605-e607

View on PubMed ↗Publisher’s paper ↗

Citation

Perrone, Elisabetta; Ghai, Kriti; Eismant, Aleksandr; Baum, Richard P. (2025). TANDEM Peptide Receptor Radionuclide Therapy Using [ 225 Ac]Ac-/[ 177 Lu]Lu-DOTA-LM3 in a Patient With Parotid Gland Metastasis From Pancreatic Neuroendocrine Neoplasm.. Clinical nuclear medicine, 50(10), e605-e607. https://doi.org/10.1097/RLU.0000000000005782