What causes fatigue?

This page has information about some of the causes of fatigue for people with pancreatic cancer, and how to manage these.

Fatigue may be caused by the pancreatic cancer or the symptoms of the cancer, or it may be a side effect of treatment. Fatigue is a very common symptom of cancer and is often called cancer-related fatigue. This page has information about these causes of fatigue, which include:

We give some tips for dealing with these here. There is also more information on other ways to deal with fatigue in the next section.

The cancer

The cancer itself can cause fatigue, although we don’t fully understand how or why this happens. People may have fatigue when they are diagnosed, even before they start treatment. Other symptoms caused by pancreatic cancer, such as problems digesting food, can also cause fatigue.

Problems with digestion and diet

The pancreas makes enzymes which help to break down your food. This is part of digestion. Your body then gets nutrients and energy from your food. Pancreatic cancer can affect digestion, which means that you don’t get the energy you need from your food. This can cause fatigue.

Problems with digestion can also cause loss of appetite, tummy discomfort, diarrhoea and sickness. These can all mean that you may eat less, and so get less energy from your food. Fatigue may also mean that you feel less like eating.

Pancreatic enzyme replacement therapy (PERT) helps to manage these problems with digestion. It replaces the enzymes that your pancreas would normally make. Common brands include Creon®, Nutrizym® and Pancrex®.

What can I do?

  • If you haven’t seen a dietitian, ask to be referred to one. They can help you make sure you get enough nutrients and energy from your food.
  • Ask your dietitian, nurse or doctor about whether you need PERT.
  • Some people may need supplements to help get all the nutrients they need. Speak to your dietitian, nurse or doctor about whether these might help.

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“The cancer affects your eating, making you weak. It affects your toilet habits, which makes you feel uncomfortable so you don’t want to eat anyway. It all has a knock-on effect – all these little things add to fatigue. It’s all connected.”

Pain

Pancreatic cancer can cause pain for some people. Pain may be linked to fatigue, although we need more research into this.

Having pain can be exhausting, and it may cause problems sleeping. Your fatigue may be worse when you have more pain and you may feel less tired when you have less pain.

What can I do?

  • Tell your doctor, nurse or GP about any pain as soon as you can. The earlier you get treatment, the better the chance of getting the pain under control.
  • Ask to be referred to the palliative care team. Palliative care provides specialist care which aims to prevent and manage complex symptoms, including pain. It’s not just for people at the end of their life.

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Problems with blood sugar levels (diabetes)

Sometimes, pancreatic cancer can cause diabetes. This is a condition where the amount of glucose (which is a type of sugar) in your blood is too high. Diabetes may make you feel tired, lethargic and confused.

If you are diagnosed with diabetes, you will need advice that is specific to you because of the cancer. There are different types of diabetes, and information on the internet may not be right for you because of the pancreatic cancer. It’s important that you eat well to maintain your weight, and that your diabetes is managed around this. Don’t try to reduce how much you eat to manage your diabetes.

If you have diabetes and haven’t seen a dietitian or diabetes nurse to help you manage it, ask your doctor or nurse to refer you.

Being sick

Pancreatic cancer can make you feel and be sick (nausea and vomiting). This can be caused by the cancer or it can be a side effect of treatment.

Being sick can be exhausting. It may also mean that you don’t absorb all the nutrients you need from your food, making you tired. But there are ways to manage sickness.

What can I do?

  • Tell your doctor or nurse if you feel or are sick. Anti-sickness medicines may help.
  • Some anti-sickness medicines can make you sleepy, so let your doctor or nurse know if you also have fatigue.
  • If you are being sick a lot (for half a day or more, or every few days) and it doesn’t improve, contact your medical team or GP.

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"She couldn’t do the everyday things she used to like getting out the house as much, the sickness made her constantly exhausted. Only rest and being able to eat what she could helped."

Advanced pancreatic cancer

Advanced pancreatic cancer is cancer that has spread to other parts of the body, such as the liver and lungs. If you have advanced cancer, you may find that the fatigue gets worse over time, and that it has more of an effect on your daily life. This is normal, but it can be upsetting for you and your family.

Your medical team may be able to change the way they manage your symptoms to help with the fatigue.

What can I do?

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“Seek medical advice, don’t just hope that it’ll pass. Confide in family members.”

Questions about symptoms and fatigue?

Speak to your doctor or nurse about any symptoms or side effects that might cause fatigue, such as problems with diet and digestion, pain or feeling sick.

You can also speak to our specialist nurses with any questions about your fatigue.

Specialist nurse Support Line
PCUK Specialist Nurse, Dianne Dobson, taking a Support Line call on the phone

Chemotherapy

Chemotherapy uses drugs to kill the cancer cells. It is one of the main treatments for pancreatic cancer. Fatigue is a common side effect of chemotherapy.

Some people find that the fatigue starts a few hours to a few days after having chemotherapy, and improves after a few days. It can take several months for the fatigue to fully improve.

What can I do?

  • See how the chemotherapy affects you, and work out how much activity you can manage. For example, you may want to do very little on the days after chemotherapy when you are more likely to have fatigue.
  • Speak to your doctor or nurse if you have fatigue. They may be able to change the dose of your chemotherapy to reduce the fatigue.

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“I was sleeping 17 hours a day. When I mentioned it to the oncology team, my chemotherapy dose was adjusted, resulting in improved wakefulness.”

"My dad has chemo on Fridays. Come Tuesday and Wednesday, he can't get out of bed. The two days are an absolute write off. After these two days though, he regains some energy and has 5 good days!"

Surgery

Surgery to remove pancreatic cancer, such as the Whipple’s operation, is major surgery. If surgery to remove the cancer isn’t possible, some people may have bypass surgery to treat a blocked duodenum or a blocked bile duct. This is also a big operation.

It is normal to feel tired and weak after surgery, and it can take several months to recover. Some people still get fatigue a year or more after surgery.

What can I do?

  • Try to gradually get back to daily activities. You may find that physical activity helps.
  • Slowly build up how much you do, but don’t overdo it. Rest when you need to.
  • It may take time for your appetite to improve. Try starting with small amounts of food often, and then gradually eat more.
  • Ask for help from friends and family after your operation.

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"It was hard to find the energy to do anything after surgery. I’m slowly improving but still regularly get times when I need to stop and sleep for an hour or so in the day."

Radiotherapy

Some people with pancreatic cancer may have radiotherapy, which is sometimes combined with chemotherapy (chemoradiotherapy). Fatigue is a common side effect of radiotherapy. You may need to travel to hospital every day for treatment and this can make fatigue worse. Fatigue can last for several weeks or months after treatment finishes.

What can I do?

  • If you have fatigue during or after radiotherapy, talk to your medical team about how to manage it.
  • See how the radiotherapy affects you, and work out how much activity you can manage.
  • Ask someone to drive you to hospital.

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Medicines

Some medicines can make you feel sleepy, especially when you first start taking them or when the dose is changed. These include opioid painkillers, like morphine, and some anti-sickness medicines such as metoclopramide and lorazepam.

What can I do?

  • Speak to your doctor or nurse if you think your medicine may be making you tired or sleepy. They may be able to change the drug, change the dose, or suggest you take it at a different time.
  • Don’t stop taking your medicine without speaking to your doctor or nurse.
  • Check whether your medicines will affect your ability to drive.

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"It took several weeks to realise that it was the metoclopramide that made me so fatigued after chemotherapy, not the chemotherapy itself."

“You don’t realise how much the medication can make somebody really tired. Once he started taking the tablets he became very lethargic and sleepy, and couldn’t do as much.”

Anaemia

Anaemia is a low level of red blood cells or haemoglobin. Haemoglobin is the part of the red blood cell that carries oxygen around the body. Anaemia can make you feel tired, dizzy, short of breath and have problems concentrating. It may have many causes, including chemotherapy. You will have regular blood tests to check your blood cell levels during chemotherapy. There are things your doctors can do to treat anaemia.

How you are feeling emotionally

When you have cancer it’s natural to feel worried, anxious, down or stressed. But sometimes these feelings can become overwhelming. Anxiety and depression can be common in people with pancreatic cancer. And depression can be linked to fatigue in people with cancer.

Your medical team may be able to help with things that might be worrying you. For example, how to get advice about financial issues, or managing at home. Dealing with problems like these may reduce stress and anxiety.

What can I do?

  • Family and friends can often provide a lot of emotional support.
  • It can also help to speak to someone affected by pancreatic cancer. We have online support sessions and an online forum where you can connect with others.
  • Our specialist nurses on the Support Line can also help with emotional support.
  • Ask your doctor or nurse about whether there are psychological therapies available that might help. These include cognitive behavioural therapy (CBT) and counselling. These can help you talk through your feelings and find ways to deal with them.

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Problems sleeping

Problems sleeping can be common in people with cancer and can make fatigue worse.

  • Your sleep may be disturbed by symptoms caused by the cancer or your treatment. These may include pain, discomfort, sickness, needing the toilet, itching or sweating.
  • Feeling anxious or worried can also make sleeping difficult.
  • For some people, going to bed at different times each evening can also make it harder to sleep at night.
  • Sometimes people with pancreatic cancer may take steroids, for example for sickness or pain. Steroids can keep you awake, so it is better to take them before midday.

Having a nap (a short sleep)

You may find that napping during the day gives you a bit more energy. If having a short nap helps, then it is fine. Try to limit how long you nap to about 30 minutes, as sleeping too long can make it harder to sleep at night. You could set an alarm so that you don’t keep sleeping. An occupational therapist can give you advice about napping.

What can I do if I have problems sleeping?

  • Talk to your medical team. They can look at whether there is a particular problem, and how to manage it.
  • Try going to bed at a regular time, as following a routine can improve your sleep.
  • Make sure your bedroom is quiet, dark and comfortable. These things can all affect your sleep.
  • If you are sweating a lot at night, use 100% cotton bedding and keep spare sets of sheets nearby so that you can change the bed easily.
  • Doing some physical activity during the day may help.
  • If you are worrying a lot at night, try to do something relaxing before you go to bed. For example, a warm bath, might help.
  • You might find that writing down your thoughts or worries helps you to stop thinking about them at night.
  • Avoid caffeine (such as coffee and tea), alcohol or sugary foods or drinks before you go to bed, as they can affect your sleep.
  • Limit how much time you spend on your phone, tablet or computer at bedtime, as this may affect your sleep.
  • Cognitive behavioural therapy may help to improve your sleep patterns.

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“Sleep helped slightly but it was difficult to switch off and sleep.”

"It helped to have quiet times during the day, sometimes in a different room to others."

Questions to ask your doctor or nurse


  • What is causing my fatigue?
  • Can my symptoms be treated, and will this help my fatigue?
  • Will treatment cause fatigue, or make it worse?
  • Would changing my treatment help the fatigue?
  • I’m not sleeping well – can you help?
  • Can I take any medicine to help me sleep?

Updated October 2022

To be reviewed October 2025