Expanding the Perspective on Chemotherapy-Induced Peripheral Neuropathy Management

Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse effect experienced by up to 68% of individuals receiving neurotoxic agents.1 CIPN-associated sensory and motor neuropathic symptoms elicit pain, limit mobility, and negatively affect an individual's activities of daily living. Specific to mobility, both sensory and motor symptoms disrupt an individual’s fine motor sensations, affect proprioception and balance, and contribute to functional limitations. The deleterious impact on proprioceptive input, in moderate to severe cases, can significantly alter postural stability, balance, and gait patterns, introducing the risk of falls.2,3

CIPN-related falls and functional deficits are common among individuals receiving chemotherapy.4 However, various studies examining the functional impact of CIPN are based on clinical trials that captured only patient self-reported measures of CIPN symptoms, symptom severity, and functional limitations.4-6 These trials retrospectively assessed functional limitations, including falls and fall-related injuries associated with CIPN, during the course of chemotherapy and over 1 year after treatment.

Predominant assumptions about CIPN are that symptoms attenuate over time, producing no or limited long-term sequelae in a majority of individuals treated with neurotoxic agents. This commonly held belief is challenged by Winters-Stone et al7 in the article that accompanies this editorial, which reports late, persistent effects of CIPN and demonstrates a significant, clinically measurable level of associated mobility impairment and functional morbidity.

Winters-Stone et al7 provide valuable and novel insight into the persistent impact of CIPN. The average individual assessed in their cohort trial was 6 years out from the completion of chemotherapy, and nearly 50% of the cohort reported persistent sensory symptoms, deficits in functional activities, and clinically meaningful measured deficits in gait and functional mobility. This appears to be the first study to combine patient self-report and valid objective measures that demonstrate clinically meaningful mobility deficits and altered gait patterns that are associated with an elevated risk of falls.

Falls are a significant problem in the population of cancer survivors. Survivors fall at a 25% to 30% higher rate than that of the general population8 and have a 15% to 20% increased risk of falling.3,9 Unique to the cancer survivor population, receiving neurotoxic chemotherapy significantly increases the risk of falls, and receiving neurotoxic doublets is associated with injurious falls.9 The health care–related economic burden associated with falls is substantial, and it is expected to escalate to nearly $55 billion by 2020.10 Importantly, falls are associated with an increased risk of death in the cancer population.11

Addressing the issue of CIPN-related falls requires a significant change in oncology clinical practice. Balance and postural stability can be markedly improved when screening and risk identification occurs early and individuals are triaged to multicomponent therapeutic programs that include targeted, task-specific balance and postural exercise.12 Winters-Stone et al7 quantify abnormal gait and mobility deficits, providing clinically relevant measures to inform triage patterns. They suggest triage for targeted therapeutic exercise that includes task-specific functional training to address mobility and proprioceptive deficits; such exercise is known to enhance postural control and gait, essential elements in promoting falls prevention.

In 2009, the National Comprehensive Cancer Network report on the management of neuropathy in cancer made recommendations for pharmacologic and conservative treatment strategies to help manage the symptoms of CIPN.13 This report provides significant context for the use of rehabilitation and therapeutic interventions that include balance and falls screening and triage recommendations for balance training activities. However, such screening and triage have yet to be elevated to routine clinical practice for individuals undergoing antineoplastic treatment with neurotoxic agents. Recommendations also abound regarding the use of valid screening and assessment tools to identify clinically meaningful CIPN-related risk.14 Furthermore, strong evidence has emerged to support falls prevention strategies and therapeutic exercises that significantly improve balance and walking in neuropathic populations.12 This expanding body of evidence supports CIPN management in a much broader context than do current recommendations and guidelines that rely heavily, and somewhat exclusively, on the use of pharmacologic agents.15 Guidelines for CIPN management should be expanded to include the assessment of gait and functional mobility and the use of therapeutic interventions that mitigate balance deficits, functional limitations, and fall risk in this population of known high risk.

Journal of Clinical Oncology , éditorial en libre accès, 2016

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