The Study

The GeoLynch study is a prospective observational cohort study designed to investigate the relationship between dietary and lifestyle factors and the development of cancer among persons with Lynch syndrome. Because of the wide scope of the study a lot of specific research questions can be answered.

The study started in 2006 as part of a collaboration between Wageningen University, the Dutch Foundation for Detection of Hereditary Tumors (StOET) and the Gastroenterology and Hepatology departments of the Radboud University Medical Center in Nijmegen and the University Medical Center in Groningen. Between 2006 and 2008 about 500 persons with Lynch syndrome started to participate. At that time, we collected data on their dietary and lifestyle habits. Between 2012 and 2017 we collected follow-up data to examine if diet and lifestyle habits have changed over the years.

From 2012, we are also inviting new people with Lynch syndrome to participate. Up until now, we have included 750 participants.

The GeoLynch study receives financial support from the Dutch Cancer Society (KWF Kankerbestrijding), the World Cancer Research Fund (WCRF) and BBMRI-NL. The study has been approved by the Central Committee on Research Involving Human Subjects of the region Arnhem-Nijmegen.

Prof Kampman:

"When we compare all the research that is done on diet and lifestyle and the development of colorectal cancer, it appears that a number of factors are important for the development of the non-hereditary type of colorectal cancer. Smoking, obesity, hardly any physical exercise, alcohol consumption and a high consumption of red meat and processed meat appear to increase the risk, while a sufficient intake of vegetables and fruit, low-fat dairy products, folic acid and aspirin appear to have a protective effect. The question that arises is: does this also apply to the hereditary type of colorectal cancer or is lifestyle not important because it is hereditary?

More information

What is the purpose?

In the GeoLynch study we would like to learn more about the influence of dietary and lifestyle factors on the development of tumours among persons with Lynch syndrome. Data from persons with Lynch syndrome who develop a tumour are compared to data from persons with Lynch syndrome who do not develop a tumour. By studying whether persons with tumours have a different dietary pattern or lifestyle than persons without tumours, we can investigate whether diet and lifestyle have affected the development of that tumour. The final purpose of the GeoLynch study is to be able to advise persons with Lynch syndrome about diet and lifestyle, so that these persons can do something to reduce their risk of developing cancer.

Who can participate?

The GeoLynch research team approaches persons with Lynch syndrome through the Dutch Foundation for the Detection of Hereditary Tumours (Stichting Opsporing Erfelijke Tumoren, de StOET). Persons that meet the inclusion criteria of the study are selected from the StOET database: we include persons between the ages of 18 and 80 from Lynch syndrome families who carry a mutation in one of the genes that are responsible for the development of Lynch syndrome.

When someone meets the inclusion criteria for the GeoLynch study, the medical specialist will be approached first to get permission to contact his/her patient. After approval by the medical specialist, the potential participant will receive a letter with information about the study as an invitation to participate in the GeoLynch study.

If someone is not registered in the StOET database, but he/she is willing to participate, this person can contact the research team. They will check if the person meets the inclusion criteria and determine whether he/she is eligible for participation.

What is expected from participants?

Participants in the GeoLynch study receive questionnaires about diet and lifestyle by mail. The participants can complete these questionnaires at home and send them back to the researchers with the return envelope. Hereafter, the participant will be contacted to make an appointment for a blood sampling. The blood sampling will be carried out at local polyclinics. Participants do not have to undergo additional colorectal examinations for the GeoLynch study. Participants already undergo a colonoscopy regularly at their own hospital. The researchers will use the results of these colonoscopies for the GeoLynch study. You can find more information about the questionnaires, blood sampling and other data the researchers collect under data collection.

Participation is without obligations. Participants can always stop without having to state a reason. They can contact the study coordinator by e-mail or phone to do so.