Expanding the Perspective on Chemotherapy-Induced Peripheral Neuropathy Management

Balance Deficits and Functional Disability in Cancer Survivors Exposed to Neurotoxic Cancer Treatments

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) persists after treatment in up to 40% of cancer survivors and has been linked with increased balance deficits, disabilities, and fall occurrences. This study aimed to comprehensively assess the links between CIPN, balance deficits, and functional disability and to inform the development of clinical screening tools for patients at risk of these events.

PATIENTS AND METHODS

A total of 190 cancer survivors exposed to neurotoxic chemotherapies (age, 57 ± 13 years; average time from completion of neurotoxic therapy, 12 ± 11 months) attended a neurology research clinic for a single cross-sectional assessment of patient-reported and objective CIPN, standing balance in 4 conditions of increasing difficulty, and functional disability.

RESULTS

Most patients (68%) reported CIPN symptoms at assessment. Symptomatic patients displayed increased functional disability (F=39.4; P<.001) and balance deficits (F=34.5; P<.001), with degree of balance impairments consistent with a healthy elderly population (age ≥65 years) reporting multiple falls over the subsequent year. Increasing CIPN severity correlated with increasing functional disability (clinically assessed R2=0.46; patient-reported R2=0.49; P<.001) and balance deficits (clinically assessed R2=0.41; patient-reported R2=0.30; P<.001). A 5-factor model of key independent correlates-patient-reported numbness/tingling, weakness, and balance deficit; age; and vibration perception-was strongly linked to balance deficits (R2=0.46; P<.001) and functional disability (R2=0.56; P<.001).

CONCLUSIONS

This study confirms links between increasing CIPN severity and increasing balance deficits and functional disability using comprehensive CIPN assessment methodology. The extent of balance deficits in patients with CIPN underscores the functional consequences of neurotoxicity. A 5-factor model provides a foundation for clinical screening tools to assess balance deficits and functional disability in patients exposed to neurotoxic chemotherapies.

Falls and Cancer

Falls among older people are common and are associated with substantial morbidity, mortality and healthcare costs. Increasingly cancer is becoming a disease of older people and fall rates are higher in elders living with cancer. Cancer and its treatments potentiate important risk factors for falls, including muscle weakness, poor balance, proprioception, cognitive impairment and functional disability. Sarcopenia refers to the progressive deterioration in muscle strength, mass and quality with ageing. Chronic conditions and cancer amplify this decline and are associated with a greater negative effect on function. Age-related impairments of lower limb neurological function are commonly exacerbated by neurotoxic chemotherapy, resulting in gait and balance deficits. Postural instability and falls erode confidence and result in a negative cycle of diminishing activity levels, further deconditioning and a higher risk of further falls. Cancer-related fatigue, sleep and mood disturbances compound this progressive frailty, further worsening treatment tolerance and outcomes. Cognitive impairment is a potent risk factor for falling and is frequently associated with gait abnormalities. The well-recognised effects of cancer treatment on working memory, attention, processing speed and executive function are often apparent (when their presence is sought) before treatment and may be as much the result of the cancer itself as they are 'chemo brain'. Structured exercise programmes focusing on progressively challenging strength and balance training are of proven benefit in falls prevention. Regular aerobic exercise accrues additional benefits in improved cardiorespiratory resilience and concomitant positive effects on treatment tolerance. Increased activity levels positively influence cognition, mood and foster an improved sense of well-being. Simple, practicable clinic-based tests of physical functioning, cognition and neurological function can help to identify those at high risk of falls and functional decline. The use of such instruments can aid judicious treatment planning and identify those most likely to benefit from more detailed specialist comprehensive geriatric assessment.

Impact of Somatic Yoga and Meditation on Fall Risk, Function, and Quality of Life for Chemotherapy-Induced Peripheral Neuropathy Syndrome in Cancer Survivors

Objective. Chemotherapy-induced peripheral neuropathy (CIPN) syndrome causes significant pain as an adverse effect of treatment, with few nonpharmacological interventions tested. A somatic yoga and meditation (SYM) intervention on functional outcomes and quality of life (QOL) was investigated. Design and methods. Individuals diagnosed with CIPN were enrolled in an open-label, single-arm, mixed-methods feasibility trial. Participants and Setting. In an outpatient rehabilitation center, ten participants with median age 64.4 years (47-81) attended 61% of the sessions with no adverse events. Intervention. SYM twice a week for 8 weeks for 1.5 hours, with home program and journaling. Main outcome measures. Primary functional outcomes included Sit and Reach (SR), Functional Reach (FR), and Timed Up and Go (TUG). Self-reported Patient Neurotoxicity Questionnaire (PNQ) and Functional Assessment of Cancer Therapy—Neurotoxicity (FACT-GOG-NTX) were secondary CIPN outcomes. Biomarkers included salivary cortisol (stress) and bioesthesiometer (vibration). Results: Quantitative findings. Significant improvements were found in flexibility (SR; P = .006); balance (FR; P = .001) and fall risk (TUG; P = .004). PNQ improved significantly (P = .003) with other measures improving non-significantly. Qualitative findings. Five themes emerged: (1) vacillation of CIPN pain perception over time; (2) transferability of skills to daily activities; (3) improvement in physical function; (4) perceived relaxation as an effect of SYM; and (5) group engagement provided a social context for not feeling isolated with CIPN. Conclusion. Preliminary data suggest SYM may improve QOL, flexibility, and balance in cancer survivors with CIPN, with a fully powered randomized controlled trial indicated.

Trial registration: NCT03786055

Efficacy of a topical gabapentin gel in a cisplatin paradigm of chemotherapy-induced peripheral neuropathy

BACKGROUND

Chemotherapy induced peripheral neuropathy (CIPN) has been attributed to chemotherapeutic agents such as cisplatin which adversely affect disease outcome leading to increased cancer related morbidity. The clinical efficacy of systemic gabapentin in neuropathic pain management is limited by central side-effects in addition to a scarceness of conclusive evidence of its efficacy in CIPN management. The topical route therefore may provide a relatively safe alternative for neuropathic pain treatment in general and CIPN in particular.

METHODS

Cisplatin induced neuropathic nociception was established in rats after a single weekly cisplatin injection (3.0 mg/kg, intraperitoneally) for 4 weeks. The evoked neuropathic sensation of allodynia was assessed by plantar application of von Frey monofilaments as the paw withdrawal threshold (PWT), whereas the expression of heat-hypoalgesia was determined on a hot-plate as paw withdrawal latency (PWL). Gabapentin gel (10% w/w) was applied three-times daily on the hind paws while in a concurrent systemic study, gabapentin was administered daily (75 mg/kg, intraperitoneally) for 4 weeks. To assess any evidence of neurological adverse symptoms of cisplatin and the central side-effect propensity of systemic or topical gabapentin, evaluation of motor coordination (rotarod test) and gait (footprint analysis) were performed.

RESULTS

Cisplatin invoked a progressive development of neuropathic hind paw allodynia (decreased PWT, days 7-28) and heat hypoalgesia (increased PWL, days 21-28). Topical gabapentin significantly delayed the expression of both allodynia on protocol days 21 and 28 and heat-hypoalgesia (day 28). Systemic gabapentin displayed a comparative anti-neuropathic predisposition through a sustained suppression of tactile allodynia on days 14 and 21-28 as well as thermal hypoalgesia (days 21 and 28). Systemic gabapentin also impaired motor coordination and gait thus affirming its clinically documented central side effects, but these outcomes were not evident after topical treatment.

CONCLUSIONS

Both topical and systemic gabapentin exhibit a propensity to attenuate CIPN in a cisplatin paradigm. Gabapentin applied topically may therefore provide an adjunctive or alternative route for CIPN management upon cessation of systemic medications due to intolerable side-effects.

Secondary Analysis Research

In secondary data analysis (SDA) studies, investigators use data collected by other researchers to address different questions. Like primary data researchers, SDA investigators must be knowledgeable about their research area to identify datasets that are a good fit for an SDA. Several sources of datasets may be useful for SDA, and examples of some of these will be discussed. Advanced practice providers must be aware of possible advantages, such as economic savings, the ability to examine clinically significant research questions in large datasets that may have been collected over time (longitudinal data), generating new hypotheses or clarifying research questions, and avoiding overburdening sensitive populations or investigating sensitive areas. When reading an SDA report, the reader should be able to determine that the authors identified the limitation or disadvantages of their research. For example, a primary dataset cannot “fit” an SDA researcher’s study exactly, SDAs are inherently limited by the inability to definitively examine causality given their retrospective nature, and data may be too old to address current issues.

Risk of incident claims for chemotherapy-induced peripheral neuropathy among women with breast cancer in a Medicare population

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and disabling consequence of neurotoxic therapies, yet factors that modulate the development and clinical impact of CIPN are poorly understood. This epidemiological analysis identifies risk factors for the incidence of CIPN.

METHODS

This retrospective analysis of Surveillance, Epidemiology, and End Results-Medicare data examined predictors of incident CIPN claims among 11,149 women aged 66 years or older with American Joint Commission on Cancer (AJCC) stage II to IV breast cancer (and no secondary cancer diagnosis or preexisting neuropathy) who received chemotherapy.

RESULTS

Overall, new CIPN claims occurred for 8.3% of patients within 1 year of starting chemotherapy. Risk emerged approximately 3 months after the start of chemotherapy and increased throughout 1 year. Paclitaxel as part of first-line therapy increased CIPN risk 2.7-fold in comparison with nonneurotoxic agents (15.9% vs 5.0%), with lower incidence rates for carboplatin and paclitaxel (11.9%), carboplatin and docetaxel (9.3%), carboplatin alone (7.7%), and docetaxel alone (6.6%). The CIPN incidence rate was higher for women who at the time of their breast cancer diagnosis were relatively young (within this Medicare sample), were at AJCC stage II or III, were married or had an equivalent status, and had fewer comorbidities, but it did not differ by race/ethnicity or poverty level.

CONCLUSIONS

These Medicare claims database findings indicate that women aged 66 years or older with breast cancer are susceptible to CIPN from taxane and/or platinum compounds, with risk emerging approximately 3 months into treatment. Prospective studies of symptom emergence and clinical response (eg, stopping chemotherapy and adjunctive treatments) are indicated to determine how best to inform patients of this risk and to manage CIPN in this population.

Factors associated with falls in older adults with cancer: a validated model from the Cancer and Aging Research Group

BACKGROUND

Falls in older adults with cancer are common, yet factors associated with fall-risk are not well-defined and may differ from the general geriatric population. This study aims to develop and validate a model of factors associated with prior falls among older adults with cancer.

METHODS

In this cross-sectional secondary analysis, two cohorts of patients aged ≥ 65 with cancer were examined to develop and validate a model of factors associated with falls in the prior 6 months. Potential independent variables, including demographic and laboratory data and a geriatric assessment (encompassing comorbidities, functional status, physical performance, medications, and psychosocial status), were identified. A multivariate model was developed in the derivation cohort using an exhaustive modeling approach. The model selected for validation offered a low Akaike Information Criteria value and included dichotomized variables for ease of clinical use. This model was then applied in the validation cohort.

RESULTS

The development cohort (N = 498) had a mean age of 73 (range 65-91). Nearly one-fifth (18.2%) reported a fall in the prior 6 months. The selected model comprised nine variables involving functional status, objective physical performance, depression, medications, and renal function. The AUC of the model was 0.72 (95% confidence intervals 0.65-0.78). In the validation cohort (N = 250), the prevalence of prior falls was 23.6%. The AUC of the model in the validation cohort was 0.62 (95% confidence intervals 0.51-0.71).

CONCLUSION

In this study, we developed and validated a model of factors associated with prior falls in older adults with cancer. Future study is needed to examine the utility of such a model in prospectively predicting incident falls.