Chemotherapy-Induced Peripheral Neuropathy Increases Risk of Falls and Physical and Functional Problems, Especially in Older Patients

Motor toxicities of chemotherapy-induced peripheral neuropathy (CIPN) are likely to lead to falls, deficits in physical performance (PP), and functional losses, according to a substudy of a phase 3 clinical trial in patients with CIPN reported at the 2012 Annual Meeting of the American Society of Clinical Oncology.¹

“This study suggests that cancer survivors who have received chemotherapy should be evaluated over time not only for CIPN toxicities, but also for physical functioning and falls,” cited Supriya Gupta Mohile, MD, of the University of Rochester Medical School in Rochester, New York. Mohile suggested that balance and mobility training should be considered during chemo­therapy to reduce the risk of falls.

Falls and PP problems are common in cancer patients, and older patients are more likely to fall than age-matched peers without cancer. Falls are a significant cause of morbidity. Prior to this study, data were limited on the relationships between CIPN and falls, PP deficits, and functional problems.

The study enrolled 461 patients who participated in a randomized, double-blind, placebo-controlled clinical trial to evaluate a topical cream in cancer survivors with CIPN. All participants had completed chemotherapy, were not on medications for pain or neuropathy, and had self-reported painful CIPN at baseline, as reflected by daily pain scores of >4 on an 11-point scale from 0 to 10 for severity. Patients also completed sensory and motor subscales of the European Organisation for Research and Treatment of Cancer quality-of-life questionnaire for neuropathy toxicities and self-reported falls.

A primary outcome measure was self-reported falls in the previous 3 months. A PP deficit was defined as finding it difficult or being unable to perform any of 6 physical tasks, including lifting objects, walking a quarter of a mile, reaching arms above shoulder level, and stooping, crouching, or kneeling. Functional losses were defined as having difficulty or being unable to perform any of 5 functional tasks: managing money, bathing, light housework, walking across the room, and shopping.

Patients who reported falls and/or PP deficits were compared with those who did not. A logistic regression analysis was performed to examine the association of baseline characteristics and CIPN toxicities with falls, PP deficits, and functional losses. Among the study population, 11.9% experienced recent falls, 58.6% reported a PP deficit, and 26.6% reported a functional loss.

Patients who reported falls and/or PP deficits were significantly more likely to be older (P = .02), female (P = .03), have less education (P <.01), and to have higher severity of CIPN toxicities: pain (P <.001), sensory (P <.001), and motor (P <.001) neuropathy (in an unadjusted analysis). Groups with falls and/or PP deficits and without these factors did not differ according to cancer and chemotherapy history.

An analysis adjusted for age, gender, race, ethnicity, marital status, education, history of taxane therapy, previous radiation therapy, cancer diagnosis, pain, and sensory neuropathy found factors independently and significantly associated with falls were a history of breast cancer (P = .045) and motor neuropathy (P = .006). Factors independently associated with having a PP deficit were previous surgery (P = .013) and motor neuropathy (P <.001). Factors that were significantly associated with functional losses included non-white race (P = .01), Hispanic ethnicity (P = .048), PP deficit (P <.0001), and motor neuropathy (P = .0001).

The study was limited by its heterogeneous cancer sample; its cross-sectional nature, which did not allow for assessment of causality and temporal relationships; and the self-reporting of CIPN toxicities. Nevertheless, the study confirmed that CIPN toxicities, primarily motor related, are significantly associated with falls, PP deficits, and functional losses.—AG

Reference

1. Mohile SG, Fan L, Gewandter JS, et al. Falls, physical performance deficits, and functional losses in cancer survivors with chemotherapy-induced neuropathy (CIPN): a University of Rochester CCOP study. Presented at: 2012 Annual Meeting of the American Society of Clinical Oncology; June 2012; Chicago, IL. Abstract 9014.