Maarten van Egmond

44 Chapter 3 MATERIALS AND METHODS Participants From 2012 to 2016, patients with esophageal cancer scheduled for esophagectomy at the Department of Surgery of the Amsterdam University Medical Centers were eligible for the study. Patients were excluded from the study when the initial indication for surgery was withdrawn or if metastasized disease was diagnosed after neoadjuvant therapy. Study design and ethics In this prospective cohort study, pre- and postoperative examinations of functional status were systematically performed. These measurements took place 3 months and 1 day preoperatively (T1 and T2) and 1 week and 3 months postoperatively (T3 and T4). The measurements performed in this study were part of physiotherapeutic care and performed in line with ‘Good Clinical Practice’. Therefore, the Medical Ethics Committee of the Amsterdam University Medical Centers waived the need for informed consent (W11-147 # 11.17.1012). Patient characteristics Pre-surgical baseline characteristics were recorded from both medical records and preoperative physical examination. Postoperative complications were prospectively recorded and defined by the Clavien-Dindo classification of surgical complications. 13 Measurements The main outcome measures were prospectively collected and recorded and contained measurements of musculoskeletal and cardiovascular functions, activities and participation, which are major components of functional status, according to the domains of the International Classification of Functioning, disability and health (ICF). The ICF framework guides effective decision-making within the rehabilitation process. 14,15 The choice of measurement instruments was based on both psychometric properties and clinical relevance. ICF: Body functions Handgrip strength (HGS) was measured with a hand held dynamometer, which is a reliable instrument to predict the total skeletal muscle strength. 3,16-18 The outcomes were compared with normative values of adults as described by Spruit et al. 19 Proximal muscle strength of the lower extremities was assessed the with the functional 30-second chair stand test (30CST). This test was validated and found to be reliable in older adults. 3,18,20 Outcomes were compared with normative values for men and women older than age 60 years. 21