For people living with neuroendocrine tumors (NETs), treatment can involve a wide range of options, from therapies that work throughout the body to ones that target tumors in a particular organ or even a specific area within an organ.
For patients with advanced NETs, interventional radiology and nuclear medicine can offer highly targeted approaches to controlling disease and managing symptoms. Two important categories are liver-directed therapies, which focus treatment on tumors in the liver, and peptide receptor radionuclide therapy (PRRT), a systemic treatment that delivers radiation to NET cells that express specific receptors.
Understanding how these treatments work and why one may be recommended over another can help patients have more informed conversations with their care team. Read on to learn more, and be sure to check out our webinar on Interventional Radiology and Nuclear Medicine in NETs for more information on this important topic.
What Are Liver-Directed Therapies?
The liver is a common site of metastatic disease in people with neuroendocrine tumors. When liver tumors cannot be treated surgically, or surgery is not appropriate for an individual patient, liver-directed therapies may provide another way to control disease. These treatments may also be considered when cancer is present elsewhere in the body, but the most significant progression is occurring in the liver.
Two primary approaches include ablation and embolization.
Ablation uses imaging to guide a probe directly into a tumor, where energy destroys the targeted tissue. It is generally most useful when there are a limited number of appropriately sized and located liver tumors.
Embolization uses the liver’s blood supply to deliver treatment to tumors. Because NET liver metastases are often highly vascular, an interventional radiologist can guide a catheter into the hepatic arteries and deliver treatment directly to the affected area.
Depending on the individual patient, this may include bland embolization, chemoembolization, or radioembolization.
Treating More Than Tumor Growth
Controlling tumor growth isn’t the only reason doctors may consider liver-directed therapy. Some neuroendocrine tumors release hormones that cause carcinoid syndrome. In these cases, treating liver tumors may also help manage hormone-related symptoms such as flushing and diarrhea.
This is an important part of NET treatment planning: how a tumor affects a patient’s quality of life can matter as much as what changes on a scan.
Patients undergoing bland embolization or chemoembolization may experience temporary abdominal pain, nausea, low-grade fever, fatigue, or flu-like symptoms. A doctor may recommend an overnight hospital stay to help manage these immediate effects.
When multiple areas of the liver require treatment, procedures may also be separated by several weeks to give the liver and the patient time to recover.
What Is PRRT?
Whereas liver-directed therapies focus on a specific organ, peptide receptor radionuclide therapy, or PRRT, is a systemic treatment that travels through the bloodstream and can reach tumors in multiple areas of the body.
PRRT targets somatostatin receptors, which are abundant on many well-differentiated neuroendocrine tumor cells. The treatment combines a molecule that binds to these receptors with a radioactive component that can damage the tumor cells.
Before treatment, a somatostatin receptor PET scan, such as a DOTATATE PET scan, helps determine whether a patient’s tumors express enough of the target receptor for PRRT to be an appropriate option.
This imaging is especially important because tumors can behave differently even within the same patient. One lesion may strongly express somatostatin receptors while another may not.
What Can Patients Expect During PRRT?
The standard PRRT schedule discussed during FLaNET’s educational webinar includes four treatments about eight weeks apart.
The radioactive therapy itself takes about 30 minutes to administer, but the full treatment appointment generally lasts several hours. Patients also receive an amino acid infusion before and after PRRT to help protect the kidneys.
Blood tests between treatments allow the care team to monitor the bone marrow, kidneys, and liver and determine whether treatment can continue as planned.
Because a small amount of radiation leaves the body after treatment, patients also receive instructions about temporary precautions at home, including careful bathroom hygiene and limiting prolonged close contact with young children and pregnant people for the recommended period.
These precautions do not mean patients need to completely isolate themselves. Each patient’s nuclear medicine team will provide specific instructions.
Local or Systemic: How Is Treatment Selected?
No single treatment pathway applies to every person with a NET. Liver-directed therapy may be considered when disease is primarily progressing in the liver, when individual liver tumors can be targeted, or when liver tumor burden is contributing to hormone-related symptoms. PRRT may be considered when disease is present in multiple areas and imaging shows sufficient somatostatin receptor expression for the treatment to target.
But these aren’t absolute rules, and disease location, tumor behavior, symptoms, previous treatments, overall health, and future treatment options all play a role.
NET treatment is often a marathon, not a sprint. The goal is always to choose a treatment that provides meaningful benefit now without unnecessarily limiting options you may need later.
Questions to Ask Your Healthcare Team
If you’re considering liver-directed therapy, PRRT, or another treatment for a neuroendocrine tumor, consider asking:
- Where is most of my disease located, and where is it currently progressing?
- Could liver-directed therapy be appropriate for my tumors?
- Would ablation or embolization be an option for me?
- Could treatment help control hormone-related symptoms and tumor growth?
- Does my imaging suggest that I may be a candidate for PRRT?
- What side effects and recovery should I expect?
- How could this treatment affect my future treatment options?
- Would my case benefit from review by a multidisciplinary NET team?
Understanding Your Options Through FLaNET
Living with a neuroendocrine tumor can involve complex treatment decisions, particularly as new therapies and technologies become available.
At FLaNET, we’re committed to providing trusted educational resources that help patients and caregivers better understand their options and take an active role in conversations about their care.
Explore our expert-led webinars, educational guides, and community resources to learn more about neuroendocrine tumors and the treatments available throughout the NET journey. We’re with you, every step of the way.