Exploring physical activity level in patients with thoracic cancer: implications for use as an outcome measure

Purpose Cachexia is common in patients with thoracic cancer impairing physical function and quality of life. New approaches which target muscle tissue are emerging and activity monitors could provide an objective assessment of their effect on physical function. We have collated data from three studies involving the use of one such monitor in order to benchmark aspects of physical activity for patients with thoracic cancer, explore how these relate to physician-rated performance status, and consider the implications for future studies. Methods Patients with thoracic cancer and an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0-2 wore an ActivPAL (TM) monitor for 1 week. The mean time spent each day in a range of activities, e.g. standing or stepping, or their frequency, e.g. number of sit-to-stand transitions, steps taken, were calculated and compared according to ECOG PS. Results Data from 84 patients (54 male; mean (SD) age, 66 (9) years) were collated. Each day, patients spent a mean (SD) of 4.3 (2.0) h upright, completed 45 (17) sit-to-stand transitions and took 4,246 (2,983) steps. There was wide variation in each activity examined. All but the number of sit-to-stand transitions differed significantly between ECOG PS categories. Conclusions These data provide a detailed insight into how physical activity levels decline across the range of ECOG PS categories studied. The wide variation in physical activity within each ECOG PS category suggests that this scale may lack sufficient sensitivity to evaluate new cachexia treatments. Our data help to inform future work in this area.