Pancreatic neuroendocrine tumors (PanNETs) are serious but far less deadly than the more common form of pancreatic cancer. The overall five-year survival rate is about 51%, compared to just 5% for pancreatic ductal adenocarcinoma, the type most people mean when they say “pancreatic cancer.” How serious your specific tumor is depends on three things: how fast the cells are growing, how far it has spread, and whether surgery can remove it.
Not All Pancreatic Cancer Is the Same
PanNETs arise from hormone-producing cells in the pancreas, not from the cells that line the pancreatic ducts. That distinction matters enormously. In a large population-based study comparing the two types, people with pancreatic adenocarcinoma had roughly four times the risk of dying compared to those with PanNETs, even after adjusting for age, tumor location, grade, and stage. If someone tells you they have pancreatic cancer, the type changes the entire picture.
PanNETs account for a small fraction of all pancreatic tumors. They tend to grow more slowly and respond to a wider range of treatments. That said, “slower” doesn’t mean harmless. Some PanNETs are aggressive, and about 18% of patients already have liver metastases at the time of diagnosis.
How Tumor Grade Predicts Behavior
After a biopsy, a pathologist looks at your tumor cells under a microscope and counts how many are actively dividing. This produces a grade, which is one of the strongest predictors of how your tumor will behave.
- Grade 1 (low grade): Fewer than 2% of cells are dividing. These tumors grow slowly and often have excellent outcomes.
- Grade 2 (intermediate grade): A moderate number of cells are dividing. Growth is faster than grade 1 but still manageable with treatment.
- Grade 3 (high grade): Cells are dividing rapidly. These tumors are more aggressive and harder to control.
Grade 1 tumors are the most common, and many people live years or even decades with them. Grade 3 tumors behave more like traditional aggressive cancers and require more intensive treatment.
Survival Rates by Stage
Stage at diagnosis is the other major factor. Based on data from people diagnosed between 2015 and 2021, the American Cancer Society reports these five-year relative survival rates:
- Localized (tumor confined to the pancreas): 91%
- Regional (spread to nearby lymph nodes or tissues): 64%
- Distant (spread to distant organs like the liver): 19%
A 91% five-year survival for localized disease is remarkably high for any pancreatic tumor. Even regional spread still carries a majority survival rate. Distant metastases lower the outlook significantly, though treatments can extend life and manage symptoms for years in many cases.
Functional vs. Nonfunctional Tumors
About 30% to 40% of PanNETs are “functional,” meaning they pump out excess hormones that cause noticeable symptoms. The rest are nonfunctional and tend to grow silently until they’re large enough to press on nearby structures or spread.
Functional tumors are named after the hormone they overproduce. An insulinoma floods the body with insulin, causing dangerously low blood sugar, dizziness, and confusion. A gastrinoma produces too much gastrin, leading to severe stomach ulcers. Others produce glucagon, causing a distinctive skin rash and weight loss, or vasoactive intestinal peptide, which triggers persistent watery diarrhea.
Functional tumors are sometimes caught earlier because their symptoms are hard to ignore. Nonfunctional tumors, which make up the majority, are more likely to be diagnosed at a later stage simply because they don’t announce themselves.
What Happens After Surgery
Surgery is the primary treatment for PanNETs that haven’t spread to distant sites, and the results are generally encouraging. In a study of 88 patients who had their tumors completely removed, the five-year recurrence-free survival was about 84% to 88%. Only 14% of patients experienced a recurrence during follow-up.
Two factors stood out as red flags for recurrence: a higher rate of cell division (Ki-67 of 5% or above) and cancer found in nearby lymph nodes. Patients with either of those risk factors had a five-year recurrence-free survival of just 53%, while those without them had a 95% chance of remaining cancer-free at five years. That’s a dramatic difference, and it’s why your pathology report matters so much in shaping your long-term outlook.
When recurrence does happen, the liver is the most common site. Even then, additional surgery or other treatments can still be effective. In the same study, overall survival didn’t differ significantly between patients who recurred and those who didn’t, suggesting that recurrences can often be managed.
Treatment for Advanced Disease
When a PanNET can’t be surgically removed or has already spread, several treatment approaches can slow its growth. One option is a targeted radiation therapy that delivers radioactive molecules directly to tumor cells. In clinical trials, this approach extended the time before the cancer progressed to about 28 months, compared to roughly 8.5 months with standard treatment. It also improved overall survival.
Other options include drugs that block the blood supply tumors need to grow, medications that interfere with cell signaling pathways, and chemotherapy for higher-grade tumors. For functional tumors, medications can also control the excess hormone production and relieve symptoms even when the tumor itself can’t be eliminated.
Genetic Connections
Most PanNETs occur sporadically, but a notable minority are linked to inherited genetic syndromes. The most well-known is MEN1 (Multiple Endocrine Neoplasia type 1), a condition that causes tumors in multiple hormone-producing glands. Between 30% and 80% of people with MEN1 develop a pancreatic neuroendocrine tumor at some point in their lives. If you’ve been diagnosed with a PanNET at a young age or have a family history of endocrine tumors, genetic testing is worth discussing.
Long-Term Monitoring
Even after successful surgery, PanNETs require years of follow-up imaging. Current guidelines recommend CT scans of the chest, abdomen, and pelvis every three to six months for the first two years, then every six to twelve months after that. This schedule reflects the reality that recurrences can appear years later, and catching them early preserves more treatment options. Many people with low-grade tumors settle into a routine of annual scans and live full, normal lives between appointments.