LEO Study

Life without colorectal cancer

The LEO study is a large-scale, scientific study conducted by the Department of Preventive Oncology at the National Center for Tumor Diseases (NCT) Heidelberg together with the Interdisciplinary Endoscopy Center Heidelberg (IEZ). Since 2020, the LEO study team has been recruiting participants in the age group 30-49 as part of the NCT Heidelberg "Proof of Concept Trial." The trial’s main objective is to discover and evaluate new screening tests that can detect colorectal cancer and its precursors earlier.

Another focus under development is risk-adapted prevention.

Please note that you can only participate in the study if you speak German.

Aim of the study

The main objective of the study is to discover and evaluate new screening tests that can detect colorectal cancer and its precursors earlier, especially in young adults in the age group of 30-49. Further, the frequency of the disease and the question of how to best identify high-risk groups in which precursors are already present is to be investigated. We want to derive recommendations for a personalized age for starting colorectal cancer screenings.

The study also researches how well the offer of a colonoscopy to examine the bowel for polyps and other suspicious changes is received within the age group of 30-49 years and what results are found. Participants of the LEO study do not commit to any examination. At any given time, they can also decide to only participate in the study parts that include filling out our online questionnaires (LEO Questionnaire I on diet and lifestyle, LEO Health Questionnaire II on health issues) or providing biospecimens to develop simple screening tests.

However, with a colonoscopy, our participants receive an offer that does not currently exist free of charge in the German health care system for this age group. If detected early, the chances of curing most types of cancer are much better. Colorectal cancer can be prevented by screening!

Study Part I

We are contacting 10,000 men and women aged 30-49 in the Rhine-Neckar region. They receive detailed study information and a consent form for participation in study part I. The sampling is approved for scientific surveys according to §46 of the Federal Registration Act (BMG).

If interested in participating, the study participants return the consent form for study part I to our study center at NCT Heidelberg. Participants will fill out the LEO questionnaire I online, which asks about already performed colorectal cancer screenings, other screening examinations, as well as about their lifestyle.

Study Part II

If certain inclusion criteria are met (no history of colorectal cancer, no previous colonoscopy), participants from study part I are invited to study part II.

With this invitation, the study participants receive relevant study information, a second consent form, and access data for the online health questionnaire of study part II by mail. Participants are offered a free large colonoscopy.

If participants are interested in further participating in the study, they are asked to return the consent form for part II to our study center at the NCT Heidelberg. Then, participants answer the LEO Health Questionnaire II online and contact the LEO study team to make an appointment on- site at the LEO study premises (see below). This appointment is to offer a preparatory and informative talk for the offered colonoscopy. Study Part II also includes consent for the collection of various biospecimens, such as blood, urine, saliva, and later, stool, which are important for the research on early detection markers. The collection of bio samples can be done without participation in the colonoscopy.

Participation in the study or in the contents of study parts I or II does not obligate the patient to undergo a colonoscopy. An appointment for a colonoscopy is only made on an individual basis after patients have been adequately informed and have subsequently given their consent.

Study Part I

1. After receiving an invitation, please complete and return the consent form for study part I. The consent form must be completed in full. A return envelope is enclosed with your invitation.

2. With the invitation, you will also receive online access data for the LEO Questionnaire I. You will find our documents for Study Part I below.

Links to the study documents for study part I: 
a) Participant information for study part I
b) Consent for Study Part I
c) For LEO study participants who have been contacted, please click here to access Questionnaire 1 (FB1).

Study Part II

3. We have received your questionnaire data, and you meet the criteria for part II of the study. We are inviting you in writing for this next part.

4. After receiving our invitation, please complete and return the consent form for study part II if you are interested in participating. A return envelope is enclosed with your invitation.

5. With the invitation, you also receive online access data for the LEO Health Questionnaire II. You can access our documents for study part II below.

Links to the study documents for study part II:

a) Participant information for study part II​​​​​​​
b) Consent for study part II​​​​​​​
c) LEO Health Questionnaire II. Information on how to activate the link to the questionnaire is in the cover letter you received from us.

6. For the discussion of study part II, the colonoscopy information, and the collection of the bio samples, we kindly ask you to make an appointment with our study team at the NCT Heidelberg by phone. Our telephone number is 06221-56 34 322, LEO Study Phone.

7. The appointment to inform you about the colonoscopy procedure takes place in the Prevention Clinic at the National Cancer Prevention Center, Berliner Str. 45 (Mathematikon), 1st floor, in Heidelberg (Phone 06221 42-4156). There, you will be informed comprehensively about the further course of the study and the colonoscopy (study part II). During the appointment, we will also ask you for a blood, saliva, urine and, (later on) a stool sample for the examination of early detection markers as well as the routine blood test in preparation for the colonoscopy (clinical blood).

8. As a thank you for your participation, you will receive our "prevention bag" with small practical suggestions for prevention (for a healthy lifestyle and cancer prevention) as well as an exit ticket for the parking lot, so you will not face any parking costs.

9. If you have decided to have a colonoscopy as part of the study, we will make an appointment with you for the colonoscopy.

10. The colonoscopy takes place at the Medical Clinic of Heidelberg University Hospital. You will be at the Interdisciplinary Endoscopy Center (IEZ) control center, Building 410, UG, in Neuenheimer Feld (INF 410) on the day of the colonoscopy. Please also bring your refrigerated stool sample to this appointment and hand it in at the control center when you register. After the colonoscopy, you will be informed about its findings.

Contact Details

The LEO study is coordinated by the Department of Preventive Oncology at the NCT Heidelberg.
We very much welcome your participation. Prevention research depends on every participant. Only if as many people as possible participate, can new cancer screening methods be developed and evaluated. Those can ensure early cancer detection through simple examinations of bio specimens, such as blood, saliva, urine or stool samples.

If you have any questions about the process, we, the LEO study team will be happy to provide further information.

Your Leo Study Team:
National Center for Tumor Diseases (NCT) Heidelberg
Preventive Oncology
Im Neuenheimer Feld 460
69120 Heidelberg
Phone: 06221-56-34322

LEO-Study rooms
National Cancer Prevention Center
Prevention clinic
Berliner Str. 45 (Mathematikon), 1. floor
69120 Heidelberg
Phone: 06221 42-4156

Study Management
National Center for Tumor Diseases (NCT) Heidelberg
and German Cancer Research Center (DKFZ)
Prof. Dr. Hermann Brenner
Im Neuenheimer Feld 460
69120 Heidelberg

Clinical Management
University Hospital Heidelberg
Interdisciplinary Endoscopy Center
Prof. Dr. Peter Sauer, senior physician Dr. Anja Schaible, MSc
Im Neuenheimer Feld 410
69120 Heidelberg

Data Protection
German Cancer Research Center (DKFZ)
Data Protection Officer
Im Neuenheimer Feld 280
69120 Heidelberg
Phone: 06221-42-0
E-mail: datenschutz@dkfz-heidelberg.de

Heidelberg University Hospital
Data Protection Officer
Im Neuenheimer Feld 672
69120 Heidelberg
Phone: 06221-56-7036
E-mail: Datenschutz@med.uni-heidelberg.de

Data protection supervisory authority
State Data Protection and Freedom-of-Information Officer in Baden-Württemberg
P.O. Box 10 29 32, 70025 Stuttgart
Phone: 0711- 61 55 41-716, Fax: 0711-61 55 41-15
E-mail: Poststelle@lfdi.bwl.de