Longitudinal Functional Outcomes Among Survivors of Childhood Lower Extremity Osteosarcoma

Purpose: Survivors of childhood lower extremity and pelvic osteosarcoma have a high burden of functional, strength, and range of motion (ROM) impairment. However, longitudinal trajectories of these outcomes have not been well studied. Methods: This longitudinal study included patients enrolled on an institutional therapeutic protocol with lower extremity or pelvic osteosarcoma. Functional assessments (functional mobility assessment, FMA) were performed at diagnosis, prior to surgery, 10–12 weeks post-surgery, end of therapy, and 6, 18, and 48 months post-therapy. Generalized mixed models were used to evaluate differences in FMA scores, strength, and ROM across time points. Results: The study included 35 patients (mean age 13.1 ± 3.4 years) with osteosarcoma of the lower extremity (n = 34) and pelvis (n = 1). The majority underwent a limb salvage procedure (74.3%). FMA scores were lowest at the pre-therapy time point (least squared (LS) mean 27.2, standard error (SE) 2.2) and highest at the 48-month follow-up time point (LS mean 48.4, SE 2.4, p-trend < 0.01). A large proportion of participants had scores indicating functional impairment throughout the study period including 80% of participants at the 48-month follow-up. Strength and ROM scores demonstrated similar trends in improvement over time; however, they remained below normative scores at long-term follow-up. Conclusions: A high burden of impairment in function, strength, and ROM persists among survivors of childhood lower extremity and pelvic osteosarcoma from diagnosis through long-term follow-up. Implications for Cancer Survivors: A lifelong focus on mitigating impairments in function, strength, and ROM is needed among survivors of childhood pelvic and lower extremity osteosarcoma.