What it means
Many neuroendocrine tumors carry somatostatin receptors, proteins that certain tracers attach to. The Krenning score grades how bright the tumors look on a scan with one of these tracers, such as a Ga-68 DOTATATE PET or an older octreotide scan. Your normal liver and spleen serve as references. Low grades mean uptake below or similar to the liver. Grade 3 is brighter than the liver, and grade 4 brighter than the spleen, which normally lights up strongly.
When it matters
The score mainly helps plan treatment. Tumors with strong uptake carry many receptors, so drugs aimed at those receptors are more likely to reach them. These include somatostatin analog injections and peptide receptor radionuclide therapy (PRRT), such as Lu-177 DOTATATE. Uptake above normal liver generally supports PRRT as an option. When uptake is low, other treatments are usually considered. A specialist team weighs the score with the tumor's grade and other scans.
Questions to ask your doctor
- Do all of my tumors show strong uptake, or only some?
- Does my score mean PRRT could be an option for me?
- How does the score fit with the grade of my tumor?
