Peptide Receptor Radionuclide Therapy (PRRT)
PRRT is an FDA-approved treatment for gastroenteropancreatic neuroendocrine tumors (GEP-NETs). GEP-NETs are tumors that typically arise in the stomach, pancreas, or bowel. They can be cancerous or noncancerous and produce debilitating symptoms. In PRRT therapy, medicine is infused into the bloodstream through an IV. A targeting agent in the medicine locates the cancer in the body and delivers a microscopic amount of radiation directly to the tumor cells, killing or damaging them with minimal harm to surrounding healthy tissue. The full PRRT treatment is given as four separate infusions, eight weeks apart. During the treatment, you will remain under the care of your cancer care provider, and you will come to the ARA Theranostics Center every eight weeks for your infusion.
PRRT may help patients with GEP-NETs obtain relief from their symptoms, including skin flushing, diarrhea, wheezing, and rapid heart rate. It can also slow the spread of the tumors, and improve the survival of patients.
HOW DOES PRRT WORK?
1) Medicine is infused through IV to target diseased cells in the body. 2) The targeting agent carries a microscopic amount of radiation to specific receptors on diseased cells. 3) After attaching, the targeting agent delivers a lethal dose of radiation to the diseased cells. 4) The radiation kills the diseased cells, leaving healthy tissue unharmed.
Candidates for PRRT
Candidates for PRRT have somatostatin receptor-positive GEP-NETS. The tumors have responded to somatostatin analogue (SSA) therapy (octreotide, lanreotide, etc.) in the past. However, despite continued SSA therapy, symptoms begin progressing, or tumors begin growing, and the patient is not a candidate for surgery. Patients have to meet specific minimum health requirements to ensure that the therapy will be well tolerated. ARA works with your physician to make sure you meet these requirements as part of your evaluation for the therapy.
PRRT has been determined by the FDA to be a safe treatment for neuroendocrine tumors. Due to the specific targeting of the treatment, tumor cells receive a high dose of radiation to kill them, but surrounding healthy cells receive only a limited amount of radiation and can survive. Any medicine that doesn’t go to the tumor cells is filtered out through the kidneys and then eliminated in the urine. Measures are taken during the treatment to protect the kidneys and bladder from radiation. You will receive instructions on what to do at home to minimize radiation exposure to others.
Side effects of PRRT
Side effects include vomiting, nausea, decreased blood cell counts, increased liver enzymes, decreased blood potassium levels, and increased glucose in the bloodstream. These are minimal and will be closely monitored and managed by your health care team. If you have serious side effects, your cancer care provider may decide to change, pause, or stop the treatment. For a more detailed list of side effects, please refer to the manufacturer’s website: www.lutathera.com/serious-side-effects.
A note on radiation exposure
PRRT will contribute to your long-term radiation exposure, which can raise your lifetime risk of developing a second cancer. However, PRRT alone has not proven to be a strong cause of cancer, and the benefits of treatment are determined to outweigh the risks.
The consultation begins with your cancer care provider who consults with ARA to see if you might benefit from PRRT. You may need studies as part of the evaluation, including blood tests and a PET/CT scan. Next, you will consult with an ARA paramedic and molecular radiologist who will review your medical history, discuss the treatment plan with you, and address questions or concerns you may have. If the evaluation demonstrates that you will benefit from the treatment, and if you wish to proceed, a date will be scheduled for your first infusion.
PRRT is administered by infusion, which is an IV (intravenous) medication given over a number of minutes or hours. It is usually given in 4 separate infusions, 8 to 16 weeks apart. The infusion and associated care take approximately 6 to 8 hours to complete on each infusion day.
The infusion process
- The infusion process lasts approximately 5 to 6 hours.
- About one hour before the PRRT infusion is started, you will be given medicine that will help with any nausea or vomiting you may experience because of the treatment.
- 30 minutes before the PRRT infusion is started, an amino acid infusion will be started through the IV to protect your kidneys. This infusion will continue while you receive the PRRT infusion and afterward for an additional 3 to 4 hours.
- The PRRT infusion will then start and will take 30 to 40 minutes.
- You will be monitored closely by the medical team to ensure that you are not experiencing any negative side effects.
Preparing and arriving
- Do not eat anything after midnight the night before your infusion day. Please take your usual medicines with a small amount of water the day of your infusion. If you are diabetic, please contact the theranostics team for additional instructions.
- Your appointment will start at 7:30 AM and be finished around 3:00 PM. Please do not schedule other activities for that day.
- Feel free to bring a book, computer, or other quiet activity to spend time on during your infusion. Wi-Fi and television are provided in the infusion room.
- If you wish, you can bring a friend or family member with you to keep you company. Your family member or caregiver may be with you during the treatment, but may be asked to leave during the 30 to 40 minutes that the PRRT infusion is given.
- After getting checked in on your infusion day, you will be brought to your private infusion room with an attached bathroom for your use. You will be given a gown, scrub pants, and socks to change into. Your street clothes will be stored safely in the infusion room with you.
- You will have a chance to ask any questions you may have about the procedure.
- A paramedic will measure your vital signs (pulse, temperature, breathing, and blood pressure) and place two IV lines, one into each of your arms or hands.
- If you have a central venous catheter (CVC), the paramedic will place one IV line into your CVC and one in your arm or hand.
After the infusion
- You will be offered a light lunch with a choice of sandwiches, snacks, and drinks. You may bring your own food if you have specific dietary requirements.
- You will be kept for a short period after the infusion to allow some of the PRRT medicine and the associated radiation to pass from your body. The medical team will let you know when it’s safe to leave.
- You will need to receive your usual dose of somatostatin analogue (SSA) within 24 hours of your PRRT infusion. This will either be given by ARA on your infusion day or by your cancer care provider on the day after the infusion, depending on what you have planned prior to the infusion day.
Your next treatment
- You may receive PRRT up to 3 more times after your first infusion. These doses are 8 weeks apart.
- You and your cancer care provider will decide how many treatments and how long between each dose is right for you.
- Between each treatment, your health care provider may check your liver and kidney function and your blood counts.
After the last treatment
- Your cancer care provider will check your liver, kidneys, and blood on a routine basis after your last infusion. You will continue receiving long-acting octreotide every 4 weeks for up to 18 months from the date you started PRRT.
Follow directions on your patient discharge instructions to safely manage the radiation in the PRRT medicine as it passes out of your body in your urine. This will protect you, as well as family members and caregivers around you. If you need medical care within the first few days after your PRRT infusion, be sure and tell your providers that you have been treated with PRRT. There may still be some radiation in your body, and your health care providers should take universal precautions. Most of the radiation will leave your body within 3 days.
Interacting with family and coworkers
- Try to maintain a distance of 6 feet from others for 3 days.
- Maintain a distance of 6 feet from infants, children, or pregnant women for more than 3 days.
- Wait 3 days before returning to work, then you may return if you feel well enough.
Interacting with pets
- Pets can be affected, too. You may want to take the same precautions with them.
Using the toilet
- Sit while using the toilet (men included).
- Use toilet paper or wipes each time.
- Flush toilet paper or wipes.
- Flush twice with the lid closed.
- Wash your hands each time you use the toilet.
- Use separate towels and washcloths.
- Sleep in a separate bed and avoid intimate contact.
Driving home from the theranostics center
- The closest you should be to someone is 3 feet, and only for up to 1 hour. So, if your spouse or caregiver is driving, consider sitting in the back seat.
Going out and about
- Minimize use of public transport and public facilities.
PRRT is covered by Medicare and many insurance groups. Your cancer care provider and the ARA theranostics team will work together to determine the details of your coverage and help you through authorization and enrollment in treatment.