PEPTIDE RECEPTOR RADIONUCLIDE THERAPY (PRRT)
Peptide Receptor Radionuclide Therapy (PRRT) is a molecular therapy (also called radioisotope therapy) used to treat a speciﬁc type of cancer called neuroendocrine tumors or NETs.
How is PRRT performed?
The most common protocol, which is the basis of the FDA and European Medicines Agency approval, includes a series of four PRRT treatments with 177Lu-DOTATATE spaced approximately two to three months apart. Local protocols may vary, though, as to the radionuclide (Lu-177 or Y-90), peptide (e.g. DOTATOC, DOTATATE), number of treatments, and dosage per treatment. In our country, this treatment is done as a full-day outpatient procedure; in rare cases a patient may need to stay overnight as a precaution.
Each PRRT session begins with the appropriate anti-nausea pre-medications, followed by an amino acid solution. The amino acid solution is delivered intravenously to protect the patient’s kidneys from the effects of the treatment. The treatment is then injected into the patient (this generally takes about 30 minutes), followed by additional amino acid solution. In total, the treatment session lasts approximately ﬁve hours.
Molecular imaging scans (e.g. post-treatment Lu- 177 scans) may be taken during and following the treatment process to see where the injected radiopeptide has traveled in the body.
What are the possible Side Effects of this treatment?
The administration of the PRRT itself is well tolerated, but patients may experience nausea and vomiting as a result of the amino acid infusion, especially with some formulations. This is managed with anti-nausea medication or slowing down the administration of the amino acids. Long-term side effects can include a suppression of blood cell counts, which is mild to moderate in the majority of cases. Delayed side effects, such as permanent renal toxicity, or the appearance of second hematologic neoplasms (called myelodysplastic syndrome), are rare. Overall, the treatment is well tolerated by most patients.