External radiation therapy may relieve symptoms from skeletal metastases. External radiation therapy otherwise does not have a place in treatment of neuroendocrine tumors.
Radioactive isotope treatment (Peptide receptor radionuclide therapy)
If a tumor is detected by an octreotide scan with somatostatin receptors, it can be treated with radioactive isotopes (radionuclides). These are attached to an octreotide analog which binds to receptors on the tumor thereby the radionuclide can deliver local radiation. A series of different radionuclides are used. The most common are 111Indium and 177Lutetium. 177Lutetium has given the best results.
This treatment option is not currently available in Norway. Patients who require this treatment are referred to Uppsala University Hospital in Uppsala, Sweden, where mainly 177Lutetium in used.
Treatment is given 1–8 times in 4–6 week intervals. The patient is isolated for the first 24 hours to protect others from radiation. The patient stays at the hospital or patient hotel for 4–7 days for each treatment.
Of those treated, 80% have a positive effect: 35% stabile disease, and 45% regress. The median time to progression is 40 months. The effect appears to be best for neuroendocrine tumors in the pancreas.
Examples of treatment effect:
- CT scan
- Octreotide scintigraphy
Common side effects are nausea and pain, which occur early in the treatment course. Cytopenia, myelodysplastic syndrome, and renal failure are side effects which are considered delayed/rare.
- Other treatments should be tried first
- There is strong uptake by the tumor on octreotide scan
- Good general health status
- Good bone marrow function
- Good renal function
- Ki67 less than 40-50%