6577 Background: Wearable physical activity monitors (PAMs) provide a degree of functional assessment not possible with prior clinical instruments. Subjective assessments of functional status are prone to inaccuracy and current objective assessment techniques are limited to the research setting. The relevance of physical activity monitors (PAMs) to measure functional status in cancer patients is unclear. The feasibility of using these devices in cancer patients is not known. Methods: This is a prospective pilot trial of a commercially available PAM in cancer patients. Patients with Eastern Cooperative Group performance status (ECOG PS) 0-2 receiving systemic therapy at an NCI Designated Comprehensive Cancer Center were enrolled. (NCT02583815). The primary objective was to determine feasibility of PAM use, defined as device use of more than 50% of the study observation period. Secondary objectives were to correlate PAM-reported measures: median, minimum and maximum steps/day, minutes of