When neuroendocrine tumors (NETs) metastasize (spread) to the liver, our team has the expertise to make crucial recommendations. We offer all options for liver-directed treatments for neuroendocrine liver metastases.
When making a plan for you to consider, we think about your overall health, your quality of life and your future. We protect the liver and preserve treatment options to use down the line.
What Is Liver-Directed Therapy for Neuroendocrine Tumors?
While NETs tend to grow slowly, they can still turn cancerous and spread. Many people develop NET metastases in the liver, from a full range of initial tumors:
Metastatic liver disease from a NET can be present at diagnosis. But cancer can also spread to the liver during treatment or recur (return) there years after effective therapy. Some people develop a single metastasis or a couple, while others experience widespread disease throughout the liver.
Regardless of the situation, liver-directed therapy can help. Our interventional radiologists use imaging to guide needles or catheters (thin tubes) to the tumors or their blood supply. You may need more than one liver-directed treatment over your course of care.
Why Choose the Abramson Cancer Center for Liver-Directed Therapy?
When a NET metastasizes to the liver, care involves a number of critical decisions. You need a team with a long history of treating these cases to recommend a personalized plan.
When you choose our program, you’ll find:
- Experience: Specialists at the Abramson Cancer Center perform 500 embolizations each year for a range of liver cancers. They know how to perform these procedures safely and effectively. The interventional radiologists on our neuroendocrine tumor team make the tumors one of their main practice areas.
- Expertise: Our liver specialists sit on committees that form national treatment guidelines. We’re also overseeing a global clinical trial to find the best options for treating NET metastases in the liver. Learn more about clinical trials for neuroendocrine tumors and research.
- Collaboration: Sometimes the liver needs surgery and sometimes it needs liver-directed therapy. Our weekly tumor board brings together a range of crucial experts who discuss which treatments to recommend and in which order.
- Support: Our nurse navigator helps arrange all of your care. We also provide a range of further support for neuroendocrine tumors.
How We Choose Treatment for Neuroendocrine Liver Metastases
If a NET metastasizes to the liver, our tumor board discusses the best treatment approach and timing.
When possible, our surgeons remove the original tumor and all metastases. This approach provides the best chance at a cure. If complete and safe removal isn’t possible, we consider:
- Extent of liver disease: We look at scans to see if there’s more cancer inside the liver than outside. If there’s more outside, we may consider treating the whole body with systemic drug therapy for NETs or nuclear medicine for NETs. If there’s more disease inside, we consider it liver-dominant and look to treat the liver sooner.
- Most pressing challenge: NET metastases in lymph nodes and bones can cause pain, but won’t threaten your life. Extensive cancer in the liver can be life-threatening, however. We might prioritize treating the liver, even when the disease is not dominant there. The liver, on the other hand, can affect survival we need to protect it.
- Potential for debulking: During debulking, we remove as much liver disease as safely possible. This approach sets back the clock in how cancer has progressed and saves liver-directed therapy for the future. (Occasionally, we need liver-directed therapy to pull disease away from critical structures, making surgery possible.)
- Behavior of original tumor: Primary tumors can release hormones, form new metastases and cause obstructions. Even if we can’t remove all cancer across the body, we may want to take out such tumors, particularly for GI NETs. Our tumor board recommends whether to address the liver or the primary tumor first.
When surgery is not possible, or not enough, we turn to other options. If we can wait to treat the liver, we may suggest a clinical trial. Otherwise, we consider several possible forms of liver-directed therapy.
Ablation for NET Liver Metastases
With ablation therapy, doctors use thin needles to reach metastatic tumors in the liver and deliver special energy that treats them. One method, cryoablation, freezes the cancerous cells. Another, microwave ablation (MWA), heats them.
Ablation reliably destroys entire tumors. It sometimes provides an alternative to surgery. We can also pair it with surgery, removing the tumors we can and freezing or heating those we find harder to reach.
Ablation does come with limits:
- It only works when there are a few small tumors — usually under three centimeters. Otherwise, the treatment leaves the liver with too many holes.
- Doctors need to see the tumors with imaging and have a clear path to reach them.
- The tumors can’t sit too close to critical parts of the liver or on the surface near other organs because of the risk for damaging healthy tissue.
Ablation Side Effects
We perform ablation as an outpatient procedure, since there are few side effects. You may experience temporary, modest:
Embolization of Liver Metastases From NETs
During embolization, doctors use catheters to access the blood vessels supplying liver tumors. They use imaging to guide them to the right spot.
Embolization can relieve symptoms, including those caused by hormone release. It also shrinks tumors in the liver by about two-thirds, on average. This impact may last for several years before further treatment is necessary.
We have two forms of embolization we can choose from. They’re similar in their effectiveness but differ in how they treat tumors. One closes blood supply and one doesn’t.
Closing Blood Supply: Bland Embolization Vs. Chemoembolization
Metastases in the liver draw most of the blood they need to live and grow from hepatic artery branches. We cut off that supply by blocking the branches with various materials. Doing so destroys cancerous cells within hours.
We usually do two treatment sessions — one for each side of the liver — spread over weeks. Healthy parts of the liver aren’t harmed because they draw their blood from a large vein — a quirk of anatomy.
We perform two variations of treatment:
- Bland embolization: Also called transarterial embolization (TAE), this procedure plugs the branch with various materials.
- Chemoembolization: Also known as transarterial chemoembolization (TACE), this technique adds chemotherapy before sealing the branch. The closure focuses the drugs on the tumor, away from healthy liver tissue.
We’re leading a global trial of these two treatments to compare their effectiveness and side effects.
For now, we discuss which approach you may prefer. People with a kidney condition frequently can’t receive chemoembolization.
Side Effects of Closing Hepatic Artery Branches
While effective and fast-acting, embolization that closes an arterial branch does come with side effects because of the sudden changes to the liver. The procedures typically cause a temporary condition called post-embolization syndrome, marked by flu-like symptoms:
- Fatigue
- Fever
- Loss of appetite
- Nausea
- Pain
- Vomiting
Half of the people receiving one of these procedures need to spend the night in the hospital. But the symptoms resolve in two to three weeks. We then check liver health before repeating treatment for the other side of the organ.
Leaving Blood Supply: Radioembolization (RE) of the Liver
Another form of embolization injects millions of microscopic seeds into the blood vessel branches feeding liver tumors. These seeds contain yttrium-90 (Y-90), an isotope that releases a special type of radiation to destroy cancer. The radiation particles are particularly heavy, so they collect on the tumor and deliver a high treatment dose.
Unlike with other embolizations, we don’t block the tumor blood supply, since radiation treatment needs oxygen to work. Because of that difference, it takes up to three months for tumors to show a response.
Radioembolization also takes place in a different way:
- It requires an extra appointment, to ensure seeds only go where we want. During the first visit, we use imaging to chart the liver’s blood supply. We then inject a mapping agent into the treatment area to see how it behaves.
- If we’re satisfied with safety, you come back several weeks later. We calculate the radiation dose and perform the isotope injection for one side of the liver. After a couple of hours of observation, you’re typically able to leave.
- If you need treatment for the other side of the liver, you return in a month.
Choosing Radioembolization and Assessing Side Effects
Since radioembolization doesn’t shut the blood supply, it doesn’t shock the liver. Only a small percentage of people spend the night in the hospital or experience strong side effects. You may feel modest:
The larger concern with radioembolization comes from radiation affecting the liver more intensely. The liver damage that may result — radiation fibrosis — usually doesn’t cause symptoms or affect health in the short term. But in the following years, 10 percent to 20 percent of people experience slow liver decline that can end with liver failure.
Since NETs often grow and spread slowly, we want to protect your long-term health. We also want to safeguard the chance to pursue nuclear medicine. While it’s likely safe to do so, we’re not sure how risks from that treatment and radioembolization might combine.
To balance the benefits and risks, we save radioembolization for special circumstances:
- Other forms of embolization haven’t worked and we need another option.
- Procedures involving the bile duct (sometimes done with pancreatic NETs) make it more vulnerable. Embolization that cuts off tumor blood supply also disrupts the bile duct, potentially triggering a complication. That risk means we want to avoid chemoembolization and bland embolization.
- People who are sicker may not tolerate other embolizations, or may not want to.
- Participants in one of our clinical trials may receive radioembolization with particular chemotherapy. The chemotherapy makes cancerous cells more sensitive to radiation. We believe this may help when the disease is somewhat more aggressive and may have spread beyond the liver.
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