There is no single best treatment for neuroendocrine cancer. The right approach depends on the tumor’s grade (how fast it’s growing), where it started, how far it has spread, and whether it’s producing excess hormones. A slow-growing tumor in the small intestine calls for a completely different strategy than an aggressive, high-grade cancer in the lung or pancreas. Most patients end up receiving a combination of treatments over time rather than relying on just one.
Why Tumor Grade Matters Most
Neuroendocrine tumors are classified into grades based on how quickly their cells are dividing, measured by something called the Ki-67 index (the percentage of cells actively reproducing). Grade 1 tumors have a Ki-67 under about 3%, meaning they grow slowly. Grade 2 tumors fall in the 3% to 20% range and grow at a moderate pace. Grade 3 tumors exceed 20% and are considered aggressive, with some having Ki-67 values above 55% or even 70% to 80%.
This grading system drives nearly every treatment decision. Low-grade tumors often respond well to treatments that would be insufficient for high-grade disease, while high-grade tumors typically need chemotherapy that would be unnecessary for slower-growing cancers.
Surgery: The Only Potential Cure
When a neuroendocrine tumor can be completely removed, surgery offers the best chance of a cure. This applies to localized tumors that haven’t spread, as well as select cases where the cancer has reached the liver but remains limited. Research from high-volume surgical centers suggests that patients with fewer than 8 liver metastases and grade 1 or 2 tumors are the strongest candidates for liver surgery, with a median recurrence-free survival of roughly 14 to 19 months after resection.
Patients with 8 or more liver metastases, or those with grade 3 disease, tend to see cancer return within about 4 months of surgery. For these patients, the risks of a major operation often outweigh the benefits. In some cases, surgeons will still perform a partial removal (debulking) specifically to control severe hormone-related symptoms like flushing and diarrhea, even when removing all visible cancer isn’t possible.
Somatostatin Analogs for Slow-Growing Tumors
For patients with well-differentiated tumors that are producing hormones or showing signs of growth, the standard first-line treatment is a class of drugs called somatostatin analogs. These are injections given every few weeks that work by mimicking a natural hormone your body uses to regulate other hormones. They serve a dual purpose: controlling symptoms like flushing, diarrhea, and wheezing caused by hormone overproduction, and slowing tumor growth.
Somatostatin analogs are typically the starting point for most patients with advanced, well-differentiated neuroendocrine tumors of the gastrointestinal tract or pancreas.
Targeted Therapy for Pancreatic NETs
When tumors progress despite somatostatin analogs, targeted drugs that block specific growth signals become an option. Two targeted therapies have strong evidence in pancreatic neuroendocrine tumors. The National Cancer Institute reported that one (sunitinib) extended the time before disease worsened to 11.4 months compared to 5.5 months with placebo. The other (everolimus) achieved similar results: 11 months versus 4.6 months with placebo. That trial, called RADIANT-3, was large enough that its results became standard practice.
Both drugs come with notable side effects, including fatigue, mouth sores, and drops in blood cell counts. Many patients need dose reductions or temporary breaks from treatment. Still, for pancreatic tumors that are progressing, these therapies roughly double the time before the cancer advances further.
The newest addition to this category is cabozantinib, which the FDA approved in March 2025 for previously treated, well-differentiated neuroendocrine tumors of both pancreatic and non-pancreatic origin. This is notable because it’s one of the few targeted drugs approved for neuroendocrine tumors outside the pancreas.
Radioactive Peptide Therapy (PRRT)
Peptide receptor radionuclide therapy, commonly called PRRT, is one of the most significant advances in neuroendocrine cancer treatment. It works by attaching a radioactive molecule to a peptide that seeks out and binds to receptors on the surface of neuroendocrine tumor cells, delivering radiation directly to the cancer while sparing most healthy tissue.
Not every patient qualifies. To be eligible, your tumor cells need to have enough of these surface receptors, which is confirmed through a specialized PET scan. If the scan shows strong uptake (rated 3 or higher on the Krenning scale), you’re a candidate. In one long-term study, 36% of patients saw their tumors shrink meaningfully. Patients with grade 1 tumors responded best, with a 60% response rate, compared to 35% for grade 2. Grade 3 tumors showed no objective responses in that analysis.
Recent data from the NETTER-2 study has expanded how PRRT is used. It showed that starting PRRT upfront, rather than waiting for other treatments to fail, is a strong option for patients with grade 2 or even grade 3 tumors, provided their Ki-67 index is 55% or lower. This has shifted practice toward earlier use of PRRT in select patients.
Chemotherapy for Aggressive Disease
High-grade neuroendocrine carcinomas (grade 3 with Ki-67 above 55%) are treated more like traditional cancers, with platinum-based chemotherapy as the standard first-line approach. This combination produces tumor shrinkage in about 42% to 44% of patients, but the overall prognosis remains poor, with a median survival around 10 months.
The picture gets more complicated for grade 3 tumors that are on the lower end of the aggressiveness spectrum (Ki-67 between 20% and 55%). These tumors respond poorly to platinum chemotherapy, with only about 15% to 25% shrinking. For this group, treatments borrowed from the grade 2 playbook often work better: temozolomide-based chemotherapy, FOLFOX (a different chemotherapy combination), PRRT, or even targeted therapies like everolimus. In fact, temozolomide-based chemotherapy has essentially replaced older regimens for pancreatic neuroendocrine tumors in the United States.
Liver-Directed Treatments for Liver Metastases
Because neuroendocrine cancers frequently spread to the liver, several treatments target liver tumors directly. These are catheter-based procedures where a doctor threads a thin tube through the blood vessels into the liver and delivers treatment directly to the tumors.
There are three main types. Bland embolization (TAE) blocks the blood supply to tumors. Chemoembolization (TACE) combines that blood supply blockage with localized chemotherapy. Radioembolization (TARE) delivers tiny radioactive beads directly into the tumor’s blood vessels, relying on radiation rather than cutting off blood flow.
Each has its niche. TARE tends to be preferred for patients who have had prior bile duct surgery (like a Whipple procedure), since the risk of liver abscess is substantially higher with TAE or TACE in that situation. TARE also works better for localized tumors where high doses of radiation can be concentrated into a small area. However, for patients with widespread liver involvement in both lobes, TARE carries concerning long-term liver toxicity risks, particularly in patients expected to live many years. Patients with scattered, low-volume liver disease (under 10% to 20% of the liver involved) may also face excess radiation to healthy liver tissue with TARE, making conventional embolization a better choice.
How Treatment Sequences Typically Work
Most patients with advanced neuroendocrine tumors will move through several treatments over months or years. A typical sequence for a well-differentiated tumor might start with somatostatin analogs, then add PRRT or a targeted therapy when the disease progresses, with liver-directed treatments used along the way if liver metastases are the main problem. For pancreatic tumors specifically, temozolomide-based chemotherapy has become a routine part of this sequence.
The relatively slow growth of many neuroendocrine tumors means patients often live with the disease for years, cycling through different treatment options as needed. Each line of therapy buys time and controls symptoms, and the expanding number of approved drugs, including cabozantinib, means more options are available at each step than even a few years ago.