Open Access Study protocol

Colorectal cancer stage at diagnosis in migrants versus non-migrants (KoMigra): study protocol of a cross-sectional study in Germany

Anne Dahlhaus123*, Corina Guethlin1, Arthur Schall1, Maja Taubenroth1, Reyn van Ewijk4, Hajo Zeeb5, Zeycan Albay1, Sylvia Schulz-Rothe1, Martin Beyer1, Ferdinand M Gerlach1, Maria Blettner4 and Andrea Siebenhofer1

Author Affiliations

1 Institute of General Practice, Goethe-University Frankfurt, Frankfurt am Main, Germany

2 German Cancer Research Center (DKFZ), Heidelberg, Germany

3 German Cancer Consortium (DKTK), Heidelberg, Germany

4 Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI), Johannes Gutenberg University Mainz, Mainz, Germany

5 Leibniz Institute for Prevention Research and Epidemiology - BIPS GmbH, Bremen, Germany

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BMC Cancer 2014, 14:123  doi:10.1186/1471-2407-14-123

Published: 24 February 2014



In Germany, about 20% of the total population have a migration background. Differences exist between migrants and non-migrants in terms of health care access and utilisation. Colorectal cancer is the second most common malignant tumour in Germany, and incidence, staging and survival chances depend, amongst other things, on ethnicity and lifestyle. The current study investigates whether stage at diagnosis differs between migrants and non-migrants with colorectal cancer in an area of high migration and attempts to identify factors that can explain any differences.


Data on tumour and migration status will be collected for 1,200 consecutive patients that have received a new, histologically verified diagnosis of colorectal cancer in a high migration area in Germany in the previous three months. The recruitment process is expected to take 16 months and will include gastroenterological private practices and certified centres for intestinal diseases. Descriptive and analytical analysis will be performed: the distribution of variables for migrants versus non-migrants and participants versus non-participants will be analysed using appropriate χ2-, t-, F- or Wilcoxon tests. Multivariable, logistic regression models will be performed, with the dependent variable being the dichotomized stage of the tumour (UICC stage I versus more advanced than UICC stage I). Odds ratios and associated 95%-confidence intervals will be calculated. Furthermore, ordered logistic regression models will be estimated, with the exact stage of the tumour at diagnosis as the dependent variable. Predictors used in the ordered logistic regression will be patient characteristics that are specific to migrants as well as patient characteristics that are not. Interaction models will be estimated in order to investigate whether the effects of patient characteristics on stage of tumour at the time of the initial diagnosis is different in migrants, compared to non-migrants.


An association of migration status or other socioeconomic variables with stage at diagnosis of colorectal cancer would be an important finding with respect to equal health care access among migrants. It would point to access barriers or different symptom appraisal and, in the long term, could contribute to the development of new health care concepts for migrants.

Trial registration

German Clinical Trials Register DRKS00005056.

Colorectal cancer; Cross-sectional; Observational study; Ethnicity; Hard-to-reach population; Health care access; Migrants