Short term Water-only Fasting prior to chemotherapy Trial (SWiFT)
Chemotherapy is an effective treatment for bowel cancer, but it can cause difficult side effects. Early laboratory research suggests that avoiding food for a short time before treatment might shield healthy cells while the medicine attacks cancer cells. The SWiFT study is testing whether it is practical for people with stage 2 or stage 3 bowel cancer to follow a 36-hour water-only fast before their chemotherapy sessions. Around 30 participants will take part. Half will drink only water for 36 hours before each of their first three chemotherapy treatments. The other half will eat their normal diet and receive standard dietary advice. Researchers want to find out whether patients can comfortably manage this routine and if it improves their well-being. The findings will help doctors design larger studies to see if fasting can reduce chemotherapy side effects in the future.
At a glance
What is this study about?
Bowel cancer (also known as colorectal cancer) is one of the most common cancers in the UK. Many people with stage 2 or stage 3 bowel cancer receive a chemotherapy combination known as CAPOX after surgery to help stop the cancer from returning. While chemotherapy works hard to destroy cancer cells, it can also damage healthy cells, leading to tiredness, sickness, and other uncomfortable side effects.
Scientists have found in early research that fasting—going without food and drinking only water for a set period—might help protect healthy cells. When cells are deprived of food, they seem to shift from growth mode into repair mode. Cancer cells do not make this switch easily. In theory, fasting could make normal cells tougher and better shielded from the harsh effects of chemotherapy, while leaving cancer cells vulnerable.
However, doctors do not yet know if fasting is genuinely helpful or manageable for people undergoing chemotherapy for bowel cancer. The SWiFT trial was set up to test whether fasting for 36 hours is safe, realistic, and acceptable for patients in everyday life.
By comparing a group of patients who fast with a group who eat as normal, the research team hopes to learn whether a larger clinical trial is possible. Even though this initial study is small, the information gathered could pave the way for simpler, drug-free ways to ease chemotherapy side effects in the future.
Key takeaways
- The SWiFT trial explores whether fasting for 36 hours before chemotherapy is practical and safe for bowel cancer patients.
- The study includes adults with stage 2 or 3 bowel cancer about to start CAPOX chemotherapy.
- Participants are randomly assigned to either drink only water for 36 hours or eat their normal diet before each of their first three treatments.
- The aim is to see if fasting can eventually help reduce difficult chemotherapy side effects.
- Taking part is voluntary, monitored by your care team, and will not delay your planned cancer treatments.
Who may be eligible?
This study is open to adults aged 18 and older who have been diagnosed with stage 2 or stage 3 bowel cancer. To be eligible, you must be due to start a course of chemotherapy called CAPOX after surgery, and you should be well enough to carry out daily tasks and look after yourself.
The study is not suitable for everyone. People who have diabetes, a history of eating disorders, or severe unmanaged weight loss cannot take part. It is also not open to anyone who is underweight, meaning having a body mass index (BMI) of 18.5 or lower, as fasting could pose health risks.
Additionally, you cannot join if you have a recent history of drug or alcohol misuse, if you cannot read or speak English comfortably (as you will need to follow instructions and complete questionnaires), or if you are already taking part in another study that might affect the results.
Could this study suit you?
Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.
- Are you aged 18 or older?
- Have you been diagnosed with stage 2 or stage 3 bowel cancer?
- Are you scheduled to begin CAPOX chemotherapy?
- Is your body mass index (BMI) higher than 18.5, and you are not underweight?
- Are you free from diabetes and any history of eating disorders?
What does participation involve?
Taking part in the SWiFT study covers your first three cycles of chemotherapy, which takes about nine weeks in total (each cycle lasts 21 days). A computer will randomly assign you to one of two groups:
• The fasting group: You will drink only water for 36 hours leading up to each of your first three chemotherapy appointments. • The normal diet group: You will eat your usual meals and receive standard NHS information and advice about diet during cancer treatment.
You will attend your regular hospital visits for CAPOX chemotherapy as planned. During these visits, the research team will check your health, ask you to complete brief surveys about how you feel, and discuss how manageable you found your eating plan. No extra hospital visits outside your standard cancer care schedule are usually required.
Potential risks and benefits
Locations (1)
- University Hospitals Bristol NHS Foundation TrustUnverifiedBristol, England
Common questions
Can I drink tea, coffee, or juice during the 36-hour fast?
No. If you are in the fasting group, you may only drink plain water during the 36 hours before your chemotherapy treatment begins.
Will fasting stop my chemotherapy from working properly?
There is no evidence that short-term fasting stops chemotherapy from working. Researchers hope it may actually help protect your normal, healthy cells during treatment.
What happens if I feel too unwell to finish the fast?
Your safety comes first. If you feel faint, dizzy, or unable to continue, you can stop fasting and eat straight away. You simply need to inform the research team.
Can I choose which group I am placed in?
No. A computer randomly puts participants into either the fasting group or the normal diet group. This ensures the study results are fair and unbiased.
Will joining this study delay my cancer treatment?
No. Your chemotherapy schedule will carry on exactly as planned by your cancer specialist.
How to find out more
Ellie Shingler
Always speak to your GP or specialist before deciding to take part in a study.
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