RecruitingOBSERVATIONAL

Cancer Loyalty Card Study 2 (CLOCS-2)

The Cancer Loyalty Card Study-2 (CLOCS-2) is looking into whether shopping information from Tesco or Boots loyalty cards could help spot certain cancers earlier. Cancers like pancreatic, bowel, oesophageal, stomach, liver, bladder, womb, vulval, and ovarian often show vague symptoms that people might try to treat themselves with over-the-counter remedies before seeing a doctor. This study compares the shopping habits of people recently diagnosed with these cancers to those without cancer to see if there are any patterns in purchases (like pain relievers or indigestion tablets) that could suggest cancer weeks or months earlier. The goal is to find ways to help people get diagnosed and treated sooner, giving them a better chance of successful treatment.

At a glance

Status

Recruiting

Sponsor

Imperial College London

Enrolment target

2,900

Start

04 Feb 2026

Estimated completion

01 Apr 2027

Pancreatic Cancer Colon Cancer Oesophageal Cancer Stomach Cancer Liver Cancer Bladder Cancer Uterine Cancer Vulvar Cancer Ovarian Cancer Endometrial Cancer

What is this study about?

Many cancers are hard to spot early because their first signs can be quite vague and easily confused with everyday health problems. People might not think these symptoms are serious enough to bother their doctor, or they might try to treat them at home with medicines bought from a chemist or supermarket. This can mean a delay in getting a diagnosis, and often by the time cancer is found, it has had more time to grow.

This study, called CLOCS-2, is looking at some specific cancers, including pancreatic, bowel, oesophageal, stomach, liver, bladder, womb, vulval, and ovarian cancers. These are some of the cancers where early symptoms are often not alarming. The researchers believe that looking at what people buy in shops using their loyalty cards (like Tesco Clubcard or Boots Advantage Card) might give clues. For example, if someone starts buying more indigestion tablets or pain relief than usual, could that be a sign something more serious is happening weeks or months before they get a cancer diagnosis?

The main idea is to see if these shopping patterns could help doctors encourage people to get checked out sooner. Catching cancer when it's still small and hasn't spread gives treatments like surgery or chemotherapy the best possible chance of working well. By understanding these purchasing habits, the study hopes to improve how quickly these specific cancers are found, leading to better outcomes for patients.

Key takeaways

It's about finding if shopping habits predict cancer.
Focuses on 10 specific cancer types.
Uses existing Tesco Clubcard or Boots Advantage Card data.
Aims for earlier diagnosis, which can improve treatment success.
Your data will be kept very secure and private.

Who may be eligible?

To take part in this study, you need to be at least 18 years old and live in the UK. You also need to be registered with an NHS doctor. If you've been diagnosed with one of ten specific cancers (bladder, bowel, womb, liver, oesophageal, ovarian, pancreatic, stomach, or vulval cancer) in the last two years, you could be part of the 'case' group. If you haven't been diagnosed with any type of cancer (except certain skin cancers) in the last six years, you could be part of the 'control' group.

Crucially, for both groups, you or someone in your household needs to have a Tesco Clubcard or Boots Advantage Card in your name. If someone else in your home has the card and makes purchases for you, they would also need to agree to join the study so the researchers can look at the card's history. You also need to be happy to share your loyalty card information with the study team and give your written consent.

Who can't join? If you're under 18, don't live in the UK, aren't registered with an NHS doctor, or don't have one of the eligible loyalty cards (or the cardholder isn't willing to join), you can't take part. Also, if you were diagnosed with one of the specific cancers more than two years ago, you wouldn't be eligible for the 'case' group.

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 18 years old or older?
Do you live in the UK and are you registered with an NHS doctor?
Do you have a Tesco Clubcard or Boots Advantage Card, or does someone in your household who shops for you?
If you have cancer, was it one of the specified types and diagnosed in the last 2 years?
If you don't have cancer, have you avoided any cancer diagnosis (except certain skin cancers) in the last 6 years?

Answer every question to see your result.

What does participation involve?

If you decide to join CLOCS-2, you won't need to visit any clinics or take any new medications. Your involvement is primarily about allowing the research team to look at your past shopping patterns. You'll be asked to provide your consent, which will be done online through a secure link (REDCap) that you'll receive by text from your GP, cancer clinic, or Be Part of Research. You can take as much time as you need to read the study information before signing up.

The main part of your participation is agreeing to share your purchase history from your Tesco Clubcard or Boots Advantage Card. The researchers will look at up to six years of this data. If someone else in your household holds the primary loyalty card but also shops for you, they would also need to agree to participate. There are no follow-up appointments or long-term assessments required once you've given consent and your data is provided. The total duration of your active involvement in the study is limited to the initial consent process and the collection of the historical loyalty card data.

Potential risks and benefits

By taking part, you won't directly benefit from this study, but your contribution could help doctors diagnose cancer earlier in the future, potentially leading to better outcomes for other patients. The main risk involves sharing your loyalty card data; however, the research team is committed to keeping all your information safe and private, storing it securely with limited access. Remember, participating is completely voluntary, and you have the right to withdraw from the study at any time without explaining why, and it will not affect your medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

Imperial College Healthcare NHS Trust
Verified postcode
London, United Kingdom· Recruiting

Common questions

What kind of information will you look at from my loyalty card?

The study will look at your past shopping records, specifically the types of products you bought, such as pain relievers or indigestion remedies.

Will my shopping habits be shared with anyone else?

No, your personal shopping information will be kept strictly private and secure within the study team and will not be shared publicly.

Do I need to change how I shop if I join?

No, you don't need to change your shopping habits at all. The study only looks at your past purchases.

How long will the study use my loyalty card data?

The study will look at up to six years of your past loyalty card purchase data.

What if I decide I don't want to be in the study anymore?

You can withdraw from the study at any time without giving a reason, and it will not affect your medical care.

How to find out more

Yuscah Pondeca

yuscah.pondeca16@imperial.ac.uk 02075942127 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.