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What causes fatigue?

Fatigue may be caused by the pancreatic cancer, be a result of symptoms caused by the cancer, or be a side effect of treatment. It’s a very common symptom and is often called cancer-related fatigue. Below are some of the causes of fatigue for people with pancreatic cancer, and how to manage them.

Problems with digestion and diet

The pancreas produces enzymes that help to break down your food (digestion). Nutrients from your food can then be absorbed into the blood and used by your body.

Pancreatic cancer can affect this process, which means that your food isn’t properly digested and you don’t get the nutrients and energy you need. Symptoms include weight loss, loss of appetite, tummy discomfort, sickness and changes to bowel habits. These can all make fatigue worse. Fatigue can also affect your appetite and desire to eat.

There are ways to manage problems with eating and digestion. Pancreatic enzyme supplements replace the enzymes that your pancreas would normally produce, and help to break down food so your body can absorb it. They can help you manage symptoms, and can make a big difference to how you feel.

If you are having problems with eating, or haven’t been prescribed enzyme supplements, speak to your nurse, doctor or dietitian. If you haven’t seen a dietitian, ask to be referred to one.

Read more about how pancreatic cancer affects your diet or download our booklet, Diet and pancreatic cancer. 

“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.”

Problems with blood sugar levels (diabetes)

The pancreas produces hormones including insulin and glucagon that control the amount of sugar in your blood. Pancreatic cancer may affect this process, so that your blood sugar level gets too high (hyperglycaemia) or too low (hypoglycaemia). High blood sugar can be a sign of diabetes.

If your sugar level is too high you may feel thirsty, pass more urine, get headaches and feel tired. These symptoms can all make fatigue worse.

Problems with blood sugar levels can be managed with tablets and injections. If you have any of these symptoms or are struggling to manage your diabetes, speak to your nurse, doctor or dietitian. If you can’t get hold of any of these professionals, speak to your GP. If you haven’t seen a dietitian, ask to be referred to one.

Being sick

Pancreatic cancer can make you feel and be sick (nausea and vomiting). Some treatments, such as chemotherapy, can also make you sick.

Being sick can be physically tiring. It can make you dehydrated, which happens when the body loses more water than it takes in. Being sick also means you won’t absorb all the nutrients you need from your food. These things can all cause fatigue. 

Depending on what’s causing your sickness, various things may help, such as anti-sickness drugs. Read more about how to manage sickness.

If you are being sick a lot (for half a day or more or every few days) and it doesn’t improve, contact your GP or medical team for advice. If you are having chemotherapy, being sick a lot can be a sign of an infection. Call the number you should have been given for urgent advice, especially if your temperature is above 37.5oC or 38oC (depending on the advice from your chemotherapy team).


Pancreatic cancer can cause pain for some people. Pain can be caused by the cancer itself, by treatment or by problems with digestion such as bloating and constipation. Your fatigue may be worse when you have more pain and you may feel less exhausted when you have less pain.

Pain can be relieved with a range of treatments, so ask your GP or medical team for help to manage it as early as you can. They can also refer you to a palliative care team or a pain clinic for more specialist advice.

Some opioid painkillers like morphine and oxycodone can also make you feel sleepy, especially when you first start taking them or when you change the dose. Drinking alcohol can make this worse.

Read more about pain and how to manage it, or download our booklet, Pain and pancreatic cancer.


Chemotherapy is one of the main treatments for pancreatic cancer. Everyone reacts differently to chemotherapy, but fatigue is a common side effect. It’s important to see how the chemotherapy affects you, and decide how much activity you can manage. It can take several months after treatment for your energy levels to get back to normal.

Speak to your doctor or nurse if you are having chemotherapy and have fatigue. They may be able to change the dose of your chemotherapy to help with the fatigue.

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


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

See how you feel, and decide how much activity you can manage. Try to take care of yourself by eating well, taking gentle exercise and making time to rest if you can.

If you have fatigue during radiotherapy, talk to your nurse or treatment team about how to manage it.


Sometimes it is possible to have surgery to remove pancreatic cancer, such as a Whipple’s operation. This is a major operation and it can take several months, or sometimes longer, to fully recover. It is normal to feel tired and weak at first. Try to balance being active with resting. Aim to gradually get back to daily activities such as walking and household tasks, but don’t overdo it.

“They said I would be tired afterwards because the Whipple’s is a major operation. My surgeon and cancer nurse said it can be a good six months before you feel anything like normal. I thought I’d be all right in a couple of months but no, it was six months.”

“After surgery, the energy needed to eat was a major challenge. I have recovered, but it did take months.”

Stents and bypass surgery

Pancreatic cancer can block the bile duct (a tube that carries bile from the liver to the duodenum). It can also block the duodenum (first part of the small intestines). You may have a stent put in or bypass surgery to relieve the blockage. Recovering from bypass surgery may take some time. You may feel tired and weak at first. It may take several weeks to be as active as you were before the operation.


Some medications can add to feelings of fatigue. For example, opioid painkillers can make you feel sleepy. Some anti-sickness drugs such as metoclopramide and lorazepam can also cause drowsiness.

If you think your medication may be making you tired or sleepy, speak to your medical team. They may be able to change it to a different drug, or suggest you take it at a different time.

“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, couldn’t do as much.”

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


If your red blood cell level is low (low red blood cell count or low haemoglobin level) you may get anaemia. Anaemia can be a side effect of chemotherapy and can cause fatigue. Your medical team can do a blood test to check your red blood cell count. If the level is very low you may need a blood transfusion.

Anxiety and depression

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

Symptoms of depression include appetite and weight loss, negative thoughts, feeling hopeless, loss of interest in things that used to give you pleasure and problems sleeping.

Read more about how depression and anxiety can be managed. Getting depression diagnosed and treated may help to reduce your fatigue and help you feel more in control.

Disturbed sleep

Your sleep may be disturbed by symptoms caused by the cancer or your treatment. These may include itching, sweating, pain, discomfort, sickness or needing the toilet. Feeling anxious or worried can cause problems sleeping too. You may also sleep badly if your bedroom is too light, too noisy, too hot or too cold. Not sleeping well can make fatigue worse.

Talk to your medical team if you aren’t sleeping well. They can look at what is causing the particular problem and how to manage it. You may also find that going to bed at a regular time each evening and following a routine can improve your sleep.

Relaxing activities like meditation or yoga can also reduce anxiety and stress so that you sleep better. Mindfulness is a technique that can help you change how you think about your experiences, and may help you deal with difficult or stressful situations. The Mental Health Foundation’s website, BeMindful.co.uk has more information about mindfulness.

“No amount of sleep makes you actually feel like you’ve had sleep. You still wake up feeling like you haven’t fully got any rest.”

“He was very uncomfortable because he was drenched with sweat every morning when he woke up. You know when you’re all hot and bothered, you’re more tired I think. You’ve not had a really good sleep.”

What can I do about fatigue?

Is there any other support to help me cope with fatigue?

Published October 2017

To be reviewed October 2019

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