vom 05/26/2020

Diabetes mellitus: A risk factor for early colorectal cancer

Scientists have analyzed data of about 13 million people in order to determine the risk of colorectal cancer in diabetic patients. Researchers of the German Cancer Research Center DKFZ) and National Center for Tumor Diseases (NCT) in Heidelberg were able to show that diabetic patients are at increased risk of developing colorectal cancer, especially before age 50 years. Diabetic patients have a similar risk of developing colorectal cancer to people with a family history of colorectal cancer.

The National Center for Tumor Diseases (NCT) Heidelberg is a joint institution of the German Cancer Research Center (DKFZ), the University Hospital Heidelberg (UKHD) and the German Cancer Aid (DKH).


Colorectal cancer is the third most common cancer in Germany and worldwide and the second most common cause of cancer death. With special concerns, scientists are observing growing numbers of young colorectal cancer patients. Thus, it is becoming increasingly important to find specific risk factors of colorectal cancer in young adults, to be able to identify high-risk individuals who would benefit most from an earlier screening. Currently in Germany, women and men are entitled to colorectal cancer screening from age 50.

Investigations point out a higher risk of developing colorectal cancer in diabetic patients, especially people with type 2 diabetes, compared to healthy individuals. Diabetes and colorectal cancer share some risk factors such as obesity, lack of exercise and metabolic factors. “So far, diabetes has not been widely recognized as a risk factor for early-onset colorectal cancer and the association between diabetes and familial colorectal cancer risk has been largely unknown”, says Mahdi Fallah, head of the Risk Adapted Prevention Group within the Division of Preventive Oncology at DKFZ and NCT Heidelberg.

Therefore, researchers in Heidelberg in cooperation with colleagues from the Lund University have analyzed data from 12.6 million Swedish citizens born after 1931 and their parents. “We intended to determine the risk of colorectal cancer, especially those diagnosed before age 50, in diabetic patients with and without colorectal cancer patients in their families”, explains Elham Kharazmi, co-leader of the study and scientist at DKFZ and NCT Heidelberg.

During the study period from 1964 to 2015, a total of 559,375 of the study population had diabetes and 162,226 people had colorectal cancer. The analysis of this world’s largest database of its kind showed that in diabetic patients the risk of colorectal cancer was elevated at all ages. The risk of developing colorectal cancer before age 50 in diabetic patients without a family history of colorectal cancer was similar to non-diabetic patients with a family history of colorectal cancer. Diabetic patients with first-degree relatives diagnosed with colorectal cancer were themselves about 7 times more likely to develop colorectal cancer before age 50 compared to individuals without diabetes and without family history.

Thus, physicians and scientists recommend that diabetic patients in Germany should participate in colorectal cancer screening, at latest when they are 50 years old. “Our study demonstrated that diabetic patients are at increased risk of developing colorectal cancer before age 50. This is an important understanding in order to prospectively offer these people a risk-adapted colorectal cancer screening earlier than the general population”, says Fallah.

Original publication:
U. Ali Khan, M. Fallah, Y. Tian, K. Sundquist, J. Sundquist, H. Brenner, E. Kharazmi. Personal History of Diabetes as Important as Family History of Colorectal Cancer for Risk of Colorectal Cancer: A Nationwide Cohort Study. The American Journal of Gastroenterology 2020; https://doi.org/10.14309/ajg.0000000000000669

Main findings of the trial:
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Press contact:
Dr. Friederike Fellenberg
National Center for Tumor Diseases Heidelberg (NCT)
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Dr. Sibylle Kohlstädt
German Cancer Research Center (DKFZ)
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Doris Rübsam-Brodkorb
Heidelberg University Hospital and Medical Faculty of the University of Heidelberg
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National Center for Tumor Diseases Heidelberg (NCT)
The National Center for Tumor Diseases (NCT) Heidelberg is a joint institution of the German Cancer Research Center, Heidelberg University Hospital (UKHD) and German Cancer Aid. The NCT's goal is to link promising approaches from cancer research with patient care from diagnosis to treatment, aftercare and prevention. This is true for diagnosis and treatment, follow-up care or prevention. The interdisciplinary tumor outpatient clinic is the central element of the NCT. Here, the patients benefit from an individual treatment plan prepared in interdisciplinary expert rounds, so-called tumor boards. Participation in clinical studies provides access to innovative therapies. The NCT thereby acts as a pioneering platform that translates novel research results from the laboratory into clinical practice. The NCT cooperates with self-help groups and supports them in their work. Since 2015, the NCT Heidelberg has maintained a partner site in Dresden. The Hopp Children's Cancer Center (KiTZ) was established in Heidelberg in 2017. The pediatric oncologists at KiTZ work together in parallel structures with the NCT Heidelberg.

German Cancer Research Center (DKFZ)
The German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) with its more than 3,000 employees is the largest biomedical research institution in Germany. More than 1,300 scientists at the DKFZ investigate how cancer develops, identify cancer risk factors and search for new strategies to prevent people from developing cancer. They are developing new methods to diagnose tumors more precisely and treat cancer patients more successfully. The DKFZ's Cancer Information Service (KID) provides patients, interested citizens and experts with individual answers to all questions on cancer.
Jointly with partners from the university hospitals, the DKFZ operates the National Center for Tumor Diseases (NCT) in Heidelberg and Dresden, and the Hopp Children's Tumour Center KiTZ in Heidelberg. In the German Consortium for Translational Cancer Research (DKTK), one of the six German Centers for Health Research, the DKFZ maintains translational centers at seven university partner locations. NCT and DKTK sites combine excellent universtity medicine with the high-profile research of the DKFZ. They contribute to the endeavor of transferring promising approaches from cancer research to the clinic and thus improving the chances of cancer patients.
The DKFZ is 90 percent financed by the Federal Ministry of Education and Research and 10 percent by the state of Baden-Württemberg. The DKFZ is a member of the Helmholtz Association of German Research Centers.

Heidelberg University Hospital (UKHD)
Heidelberg University Hospital (UKHD) is one of the most important medical centers in Germany; Heidelberg University's Medical Faculty is one of Europe's most prestigious biomedical research facilities. Their shared objective is the development of innovative diagnostics and treatments and their prompt implementation for the benefit of the patient. The hospital and faculty employ approximately 13,000 individuals and are involved in training and qualification. Every year approximately 65,000 patients are treated as inpatients and 56,000 as day patients in more than 50 specialized clinical departments with around 2,000 beds, with more than 1 million patients being treated as outpatients. Together with the German Cancer Research Center and German Cancer Aid, the Heidelberg University Hospital established The National Center for Tumor Diseases (NCT) Heidelberg as the leading oncology center of excellence in Germany. The Heidelberg Curriculum Medicinale (HeiCuMed) is at the forefront of medical training in Germany. At present 3,700 aspiring physicians and doctors are studying in Heidelberg.