Postoperative recovery is measured as a change in the Quality of Recovery-15 questionnaire. Through 15 questions, the time spent in common postoperative conditions during the last 24 hours is estimated. Each question has a scale from 0 to 10, resulting in a maximum total score of 150.

Activities in daily living are assessed using the Functional Recovery Score (FRS) to evaluate functional recovery after surgery. The eleven-item questionnaire comprises three main components: basic activities of daily living (BADL), assessed by four items; instrumental activities of daily living (IADL), assessed by six items; and mobility, assessed by one item. BADL accounts for 44 percent of the score, IADL for 23 percent, and mobility for 33 percent. Complete independence results in a score of 100 percent.

Energy and protein intake will be estimated using the 24-hour dietary recall interview method. The interviews will be conducted by the investigator working on the study. The foods and drinks will be entered into the software program Vitakost to calculate the intake of protein (g) and energy (kJ) and liquid (mL). The participant's body weight will be used to calculate the intake per kilogram of body weight. The cut-off for suspecting underreporting will be evaluated retrospectively on an individual basis, taking into account any illness, readmissions, loss of body weight, activity level etc.

Appetite will be assessed using the Simplified Nutritional Appetite Questionnaire (SNAQ), which consists of four questions adressing appetite, taste, satiety, and meal frequency. Each question offers five possible answers, and participants select the category that best reflects their current situation. The total score ranges from 5 to 20.

Physical function and muscle strength will be assessed using the 30-second chair stand test (30s CST), which measures the number of times an individual can rise from and sit down in a standardized chair within 30 seconds. To accommodate participants' abilities, the chair stand test will be modified according to three versions as needed.

Total and appendicular muscle mass (kg and percent) will be measured by bioelectrical impedance analysis (BIA). This method involves passing a low-level electrical current through the body to measure electrical impedance, or resistance, encountered by the current as it flows through different tissues. Tissues rich in electrolyte-containing water, such as skeletal muscle, have lower resistance and thus higher conductivity. Conductivity is directly proportional to total body water. Lean muscle mass is derived from the conductivity measurement, and fat mass (in kilograms and percentage) is subsequently calculated by subtracting lean muscle mass from total body weight.

Body weight and height are entered manually to aid in calculations.

Readmission rate is defined as any unplanned hospitalisation within 30 days after discharge from hospital.

The occurrence of post-operative complications, including infections requiring treatment within 30 and 90 days will be registered numerically.

The occurence of reoperations will be registered

Muscle mass by will be measured by computed tomography (CT) scan. All CT scans are part of routine care concerning the cancer disease and are therefore not research-related add-ons to routine care.