Adult Age Distribution Aged Aged, 80 and over Chemotherapy, Adjuvant Chi-Square Distribution Colectomy--methods Colorectal Neoplasms--epidemiology Combined Modality Therapy Female Greece--epidemiology Hospitals, University Humans Incidence Male Middle Aged Neoplasm Staging Probability Prognosis Radiotherapy, Adjuvant Retrospective Studies Risk Assessment Sex Distribution Survival Analysis