Patient and disease characteristics related to the collective used in this study and to the two found clinical relevant clusters.

pT category: depth of tumour invasion; pN category: presence of lymph node metastases; cM category: presence of distant metastases at the time of resection (all classification according to UICC). The p-values for cluster comparison using Chi2-test (for age Mann-Whitney U test) are given. Significant differences were found for lymph node and distant metastases status (bold).