Daily Step Counts: A New Prognostic Factor in Locally Advanced Non-Small Cell Lung Cancer?

Purpose: Here we explore the prognostic value of baseline step count data captured using wearable devices for patients treated with definitive chemoradiation therapy for locally advanced non-small cell lung cancer (NSCLC). Methods and Materials: Patients with locally advanced NSCLC wore a commercial fitness tracker during a course of definitive, concurrent chemoradiation therapy as part of a clinical trial. Baseline step count average was defined as the average daily step total from study enrollment until completion of the first week of radiation therapy. Based on data from healthy individuals, study subjects were categorized as inactive (below the 25th percentile), moderately active (25th to 75th percentile), or highly active (above the 75th percentile). Fisher's exact test was used to examine activity level as a predictor of hospitalization during radiation therapy and of completing the planned radiation therapy course without delay exceeding 1 week. Median progression-free survival (PFS) and overall survival (OS) durations were estimated using the Kaplan-Meier method. Inactivity was tested as a predictor of PFS and OS using Cox proportional hazards models. Results: Fifty subjects met eligibility criteria. Nine (18%) were categorized as highly active, 23 (46%) were moderately active, and 18 (36%) were inactive. Inactive subjects were more likely to be hospitalized during the radiation therapy course than other subjects (50% vs 9%, P = .004) and less likely to complete radiation therapy without delay exceeding 1 week (67% vs 97%, P = .006). Median PFS duration was 5.3 months for inactive subjects and 18.3 months for others (hazard ratio for inactivity = 5.10, P < .001). Median OS duration was 15.0 months for inactive subjects and not reached for others (hazard ratio = 3.91, P = .004). Performance status was not a significant predictor of PFS or OS. Conclusions: Baseline activity level measured using wearable devices may help identify patients with NSCLC who are fit for concurrent chemoradiation therapy and can predict clinical outcomes in this setting.