About CLOCS

Play video

Today, in the digital age, we live with a wealth of data at our fingertips. Studies like this are a great example of how we can harness this information for good and help us detect cancer earlier” Dr David Crosby Cancer Research UK

Every year, thousands of people are diagnosed with cancer too late - when treatment is harder and outcomes are worse. But what if we could spot the signs earlier, using something as ordinary as your shopping habits?

The CLOCS (Cancer Loyalty Card Study) initiative is exploring whether the things people buy—like painkillers, antacids, or herbal remedies - could reveal early clues about undiagnosed cancer. Many people try to manage vague symptoms themselves before seeing a doctor. These self-care choices often show up in loyalty card data from high street retailers like Tesco and Boots.

CLOCS explores whether shopping habits - captured through loyalty card data - can help identify undiagnosed cancer earlier as the first of many steps on the road to beating cancer.

Impact

• Compare shopping patterns of people with and without cancer
• Analyze up to six years of loyalty card data from Tesco and Boots
• Develop tools to encourage earlier help-seeking
• Support public health efforts to improve early diagnosis

Why participate

• Early diagnosis saves lives
• Real-world data like loyalty card purchases could help spot cancer sooner
• This research could lead to new public health tools that prompt people to seek help earlier—potentially before symptoms become serious

CLOCS-2 is a bold step toward using everyday data for extraordinary impact. With your help, we can turn shopping receipts into life-saving insights.

Who can take part

• Adults aged 18+ living in the UK, registered with an NHS GP
• Primary cardholders of Tesco Clubcard or Boots Advantage Card
• Either recently diagnosed with one of 10 cancers or no diagnosis in the last 6 years