A study looking at genetic causes of cancer (SEARCH study)

Cancer type:

All cancer types

Status:

Results

Phase:

Other

This study was done to find out more about possible genetic causes of several different cancers.

It was open for people to join between 1996 and 2019. The team have published many articles in various medical journals about the results of the study.

More about this trial

There are many factors that increase or decrease our risk of developing cancer. One is our genes and genetic variation. 

DNA is a molecule inside our cells that contains our genetic code. This code tells each cell what proteins to make and what to do. Sometimes the code is altered. This results in a change in the gene – or a genetic variant. You may also hear the term genetic mutation.

Sometimes we inherit genetic variants from one or both of our parents. But some genetic variants are not inherited. They happen at some point during our lives. 

Some genetic variants are associated with a high risk of cancer. These are rare. Other variants are associated with a small increase in the risk of cancer. These are more common. But because they don’t change the risk of developing cancer as much, they are harder to identify.

In this study, the research team looked at genetic variation in thousands of people with cancer. They also looked at thousands of people without cancer. They are called the controls.

The main aims of this study were to:

  • find out more about high risk genetic variants we already knew about
  • identify new low, moderate and high risk variants
  • identify other factors that may interact with our genes to increase the risk of developing cancer
  • identify genetic and other factors that could affect how well people do and how well cancer treatments work

Summary of results

Study design
This study was for people who had been diagnosed with cancer.

The people taking part:

  • filled out questionnaires about their health and lifestyle
  • gave a blood sample

The research team then looked at all the medical, lifestyle and genetic information to see if they could find out more about the causes of cancer.

Results
Nearly 37,000 people with cancer took part in this study:

  • 15,500 women with breast cancer
  • 200 men with breast cancer
  • 4,800 men and women with bowel cancer
  • 4,700 men with prostate cancer
  • 3,900 women with ovarian cancer
  • 2,900 men and women with melanoma
  • 3,700 women with uterine cancer
  • 1,000 men and women with other cancers

And about 3,400 people without cancer took part. These are called the controls. The research team looked for differences between those with cancer and those without.

The team have published many papers about what they have discovered by looking at the genetic changes of people with cancer.

So far, they have found out things such as:

  • fewer than 2 out of 100 women with breast cancer (2%) have a high risk BRCA1 or BRCA2 gene variant
  • around 8 in 100 men with breast cancer (8%) have a high risk BRCA1 or BRCA2 gene variant
  • fewer than 3 out of 100 women with ovarian cancer (3%) have a BRCA gene change
  • variants of genes called PALB2, CHEK2, ATM, RAD51C, RAD51D and BARD1 can cause a moderate or high increased risk of breast cancer
  • variants of genes called RAD51C, RAD51D, PALB2 and BRIP1 can increase the risk of ovarian cancer

When they looked at how many cases of cancer were linked to a family history, they found it was:

  • 12 out of 100 cases of breast cancer (12%)
  • 20 out of 100 cases of bowel cancer (20%)
  • 10 out of 100 cases of ovarian cancer (10%)
  • 15 out of 100 cases of womb cancer (15%)

Working together with other scientists from around the world they have also identified many low risk variants:

  • over 180 for breast cancer
  • 80 for bowel cancer
  • over 250 for prostate cancer
  • 40 for ovarian cancer
  • 15 for womb cancer

The information gathered as part of this study has also been used to help develop two online tools. 

One is called PREDICT. It can be used to help women with breast cancer and their doctors make decisions about treatment. 

The other is called CanRisk. It can be used to help predict someone’s risk of developing cancer in the future.

It has also been used to shape guidelines on how to assess and manage people’s risk of cancer.

More detailed information
There is more information about this research on the SEARCH study website. This is part of the website for the Centre for Cancer Genetic Epidemiology at The University of Cambridge.

The website includes a list of the publications from the study (website accessed February 2023).

Please note, these articles may not be in plain English. They have been written for health care professionals and researchers.

Where this information comes from    
We have based this summary on the information on the SEARCH website above. The articles listed have been published in various peer reviewed medical journals. We have not analysed the data ourselves.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Professor Antonis Antoniou
Professor Paul Pharoah
Professor Doug Easton
Professor Alison Dunning

Supported by

Cancer Research UK
Experimental Cancer Medicine Centre (ECMC)
NIHR Clinical Research Network: Cancer
NIHR Cambridge Biomedical Research Centre
US National Institutes for Health
European Union FP7 and Horizon 2020

If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

526

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Around 1 in 5 people take part in clinical trials

3 phases of trials

Around 1 in 5 people diagnosed with cancer in the UK take part in a clinical trial.

Last reviewed:

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