Neuromuscular impairments in adult survivors of childhood acute lymphoblastic leukemia

Abstract

Introduction—Treatment regimens for childhood acute lymphoblastic leukemia (ALL) contain neurotoxic agents that may interfere with neuromuscular health. This study examined associations between neuromuscular impairments and physical function, and between neuromuscular impairments, and doses of vincristine and intrathecal methotrexate used to treat leukemia among survivors of childhood ALL. Methods—ALL survivors 10+ years from diagnosis participated in neuromuscular performance testing. Treatment data were abstracted from medical records. Regression models were used to evaluate associations between treatment factors, neuromuscular impairments and physical performance. Results—Among 415 survivors (median age 35 years; range 21–52), balance, mobility and sixminute walk (6MW) distances were 1.3 standard deviations below age- and sex-specific values in 15.4%, 3.6% and 46.5% of participants, respectively. Impairments included absent Achilles tendon reflexes (39.5%), active dorsiflexion range of motion (ROM) < 5 degrees (33.5%) and impaired knee extension strength (30.1%). In adjusted models (including cranial radiation), survivors treated with intrathecal methotrexate cumulative doses 215+ mg/m2 were 3.4 (95% CI 1.2–9.8) times more likely than survivors who received no intrathecal methotrexate, and those who received vincristine cumulative doses 39+ mg/m2 1.5 (95% CI 1.0–2.5) times more likely than those who received lower doses to have impaired ROM. Higher intrathecal methotrexate doses were associated with reduced knee extension strength and 6MW distances. Conclusion—Neuromuscular impairments are prevalent in childhood ALL survivors and interfere with physical performance. Higher cumulative doses of vincristine and/or intrathecal methotrexate are associated with long-term neuromuscular impairments, which have implications on future function as these survivors age.