Certain pancreatic or liver cancers can cause low blood sugar. However, most of the time, low blood sugar isn’t caused by cancer.

Low blood sugar is a common problem with many causes that can cause symptoms like:

  • irritability
  • shakiness
  • poor focus

Low blood sugar is medically known as hypoglycemia. Low blood sugar that occurs shortly after eating is called reactive hypoglycemia.

Low blood sugar or reactive hypoglycemia can be the initial sign of some types of cancer, such as certain pancreatic or liver cancers. However, low blood sugar usually is not a sign of a serious underlying medical condition or cancer.

Read on to learn more about the link between low blood sugar and certain cancers.

Hypoglycemia can be a symptom of some pancreatic cancers as well as some cancers in other parts of your body.

Insulinoma

Insulinomas are tumors that develop in beta cells in your pancreas that produce insulin. They’re rare and only affect about 0.4 per 100,000 people. Other symptoms can include:

  • weakness
  • tiredness
  • headaches
  • eye problems
  • forgetfulness
  • confusion
  • behavioral changes
  • sweating and tumors
  • heart palpitations

Neuroendocrine tumors

Neuroendocrine tumors can develop anywhere in your body, but they most commonly occur in your lungs, pancreas, or gastrointestinal tract.

Insulinomas are one of the most common types of neuroendocrine tumors that cause low blood sugar. In rare cases, neuroendocrine tumors in other locations may also cause low blood sugar.

For example, in a 2024 case study, researchers reported a 19-year-old with an appendix tumor who developed recurrent low blood sugar before his diagnosis. A 2020 case study reported similar symptoms in a 34-year-old man with a tumor in his appendix.

Liver cancer

Low blood sugar is a potential symptom of liver cancer and cancers that spread to your liver from other parts of your body.

Paraneoplastic hypoglycemia

Paraneoplastic hypoglycemia is a rare condition that develops when tumors outside the pancreas produce excess hormones. It can develop when cancer cells produce excess insulin-like growth factors and other molecules that activate insulin receptors.

A wide range of cancers have been linked to paraneoplastic hypoglycemia. Some of these include:

Here’s how these types of tumors may cause hypoglycemia or reactive hypoglycemia.

Insulinomas and neuroendocrine tumors

Low blood sugar can be a symptom of insulinoma since your tumor might lead to the overproduction of insulin from your pancreas. Low blood sugar is the most common symptom of these tumors.

Neuroendocrine tumors

Some neuroendocrine tumors outside your pancreas in other places like your small intestines or appendix may also cause excessive insulin that can lead to low blood sugar.

Paraneoplastic hypoglycemia

Many types of tumors can produce excessive hormones that can cause problems in many parts of your body. Cancers that produce insulin-like growth factors can overstimulate insulin receptors and lead to low blood sugar.

Liver cancer

Your liver holds glucose and acts as a reservoir to help keep your blood sugar levels stable. Liver cancer can lead to low blood sugar if your liver isn’t able to hold onto enough sugar to meet your body’s demands.

Reactive hypoglycemia is when low blood sugar occurs shortly after eating. It’s a common problem that often occurs without an underlying medical condition, especially if you exercise shortly after eating.

Symptoms of low blood sugar can include:

Reactive hypoglycemia often doesn’t need treatment if goes away by itself. Making some dietary changes, such as avoiding large portions of high-glycemic carbohydrates, may be enough to improve your symptoms.

If your symptoms are persistent, your doctor may want to run tests to make sure there isn’t an underlying medical problem contributing to your symptoms.

Pancreatic cancer treatments

If you have pancreatic cancer, you may need treatments such as:

  • surgery
  • chemotherapy
  • hormone therapy
  • hepatic arterial occlusion or chemoembolization
  • targeted therapy
  • supportive treatments

Your doctor may recommend steroids to help keep your insulin levels low.

About 88% of people live at least 10 years after surgical removal of an insulinoma.

General ways you can prevent reactive hypoglycemia include:

Tumors that develop in your pancreas and some other parts of your body, such as your liver, can lead to low blood sugar. However, most of the time, low blood sugar isn’t caused by cancer.

If you’re frequently experiencing low blood sugar or if your symptoms are getting worse, it’s a good idea to visit a doctor. Your doctor can give you tips to manage your symptoms and rule out cancer.