METHODS
This prospective cohort study included patients with colon or rectal cancer who were scheduled to undergo surgery. Only patients who provided informed consent were allowed to participate. The institutional review boards of the participating hospitals approved the study, and all study data were kept confidential. A detailed description of the study protocol has been published previously.3
Patients were eligible for this study if they were on the surgical waiting list of one of the participating hospitals and had a diagnosis of surgically resectable colon or rectal cancer. The exclusion criteria were in situ cancer, an unresectable tumor, terminal disease, and inability to respond to questionnaires for any reason or any severe mental or physical conditions that might prevent the patient from responding to questionnaires, as well as a lack of consent to participate.
Data collection
Data collected at hospital admission included sociodemographic and clinical data, including information about comorbidities based on the Charlson Comorbidity Index 4), preoperative data, pathology data including TNM stage and infiltrated lymph nodes, and data related to the period of admission after surgery. Data were collected at 1, 2, 3 and 5 years after surgery. The information collected at those points in time included the need for radiation therapy and/or chemotherapy, performance of CT scanning, colonoscopy, laboratory test results, diagnostic tests performed, any complications, tumor recurrence, readmission or reoperation, and death.
Patients completed the following questionnaires before surgery and at 1, 2, 3 and 5 years after surgery: the Hospital Anxiety and Depression Scale (HADS) 5, the EuroQol-5D (EQ-5D)6, and the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-Q30 7. The HADS is a screening tool for anxiety and depression in nonpsychiatric clinical populations 8. The EQ-5D is a generic health-related quality of life (HRQoL) questionnaire that has good psychometric properties. It allows comparison with other populations, as well as re-evaluations 9. The EORTC QLQ-C30 is a questionnaire for evaluating the HRQoL of cancer patients undergoing treatment.
The main outcomes of the study were mortality, complications (as defined elsewhere 3) and tumor recurrence, all at 1, 2, 3 and 5 years, and patient-reported outcomes (changes in the EQ-5D, EORTC QLQ-C30, and HADS scores from baseline to 1, 2, 3 and 5 years after the intervention). The main independent variables included were CT scanning, colonoscopy, chemotherapy and radiotherapy performed at each time point.