Functional Recovery as a Survivorship Endpoint in Early-Stage NSCLC

Advances in screening, surgical techniques, perioperative care, and multimodality treatment have progressively expanded the population of long-term survivors with early-stage non-small cell lung cancer (NSCLC). However, disease-free survival does not necessarily correspond to complete functional recovery after curative-intent treatment. Many patients continue to experience persistent fatigue, dyspnea, reduced physical activity, impaired exercise tolerance, muscle loss, and deterioration in health-related quality of life despite adequate oncologic control. This narrative review discusses functional recovery as a survivorship endpoint in early-stage NSCLC, focusing on recovery trajectories, physiologic vulnerability, frailty, sarcopenia, rehabilitation, symptom burden, and emerging biologic frameworks such as allostatic load. Increasing evidence suggests that survivorship after NSCLC should not be interpreted exclusively according to recurrence or survival metrics, but also according to the ability to recover physiologic reserve, autonomy, and daily functioning after treatment. Functional recovery appears heterogeneous and influenced by multiple interacting factors, including baseline reserve, systemic inflammation, physical inactivity, behavioral adaptation, and cumulative stress burden. Rehabilitation strategies, structured symptom surveillance, and patient-reported outcomes may help identify vulnerable patients and improve long-term survivorship trajectories. Future survivorship models should probably integrate oncologic outcomes with longitudinal functional assessment to better characterize recovery patterns after treatment.