Chemotherapy-Induced Peripheral Neuropathy (CIPN): A Narrative Review and Proposed Theoretical Model.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating symptom experienced by cancer survivors. Despite the burden of CIPN-related symptoms, interventions remain limited. OBJECTIVES: This narrative review seeks to propose a framework for CIPN predisposing, precipitating, and perpetuating factors (3Ps), which will provide a foundation for future research and clinical interventions aimed at mitigating CIPN-related symptoms and morbidity. METHODS: A comprehensive literature search was performed using PubMed, guided by keywords related to "chemotherapy-induced peripheral neuropathy." Studies were limited to those with full text available in English. RESULTS: Predisposing factors outlined in this framework, such as older age and comorbid conditions, can be used to identify patients who have a higher risk of developing CIPN. The major precipitating factor of CIPN is the delivery of chemotherapy to peripheral nerves, which may be mitigated via cryotherapy or compression therapy during chemotherapy. Perpetuating factors can offer insight into psychological, cognitive, and behavioral modifications that could be treatment targets for CIPN management. CONCLUSION: The proposed 3P model can guide the development of effective interventions for CIPN by suggesting modifiable psychological and behavioral treatment targets that may mitigate the impact of CIPN for cancer patients.

Relationships among Inflammatory Biomarkers and Objectively Assessed Physical Activity and Sleep during and after Chemotherapy for Gynecologic Malignancies.

Little is known regarding associations between inflammatory biomarkers and objectively measured physical activity and sleep during and after chemotherapy for gynecologic cancer; thus, we conducted a longitudinal study to address this gap. Women with gynecologic cancer (patients) and non-cancer controls (controls) completed assessments before chemotherapy cycles 1, 3, and 6 (controls assessed contemporaneously), as well as at 6- and 12-month follow-ups. Physical activity and sleep were measured using wrist-worn actigraphs and sleep diaries, and blood was drawn to quantify circulating levels of inflammatory markers. Linear and quadratic random-effects mixed models and random-effects fluctuation mixed models were used to examine physical activity and sleep over time, as well as the associations with inflammatory biomarkers. On average, patients (n = 97) and controls (n = 104) were 62 and 58 years old, respectively. Compared to controls, patients were less active, more sedentary, had more time awake after sleep onset, and had lower sleep efficiency (p-values < 0.05). Across groups, higher levels of TNF-α were associated with more sedentary time and less efficient sleep (p-values ≤ 0.05). Higher levels of IL-1ß, TNF-α, and IL-6 were associated with lower levels of light physical activity (p-values < 0.05). Associations between inflammatory biomarkers, physical activity, and sleep did not differ between patients and controls. Given these results, we speculate that inflammation may contribute to less physical activity and more sleep problems that persist even 12 months after completing chemotherapy.

Relationships among Inflammatory Biomarkers and Self-Reported Treatment-Related Symptoms in Patients Treated with Chemotherapy for Gynecologic Cancer: A Controlled Comparison.

Previous research suggests that inflammation triggers cancer-treatment-related symptoms (i.e., fatigue, depression, and disruptions in sleep and physical activity), but evidence is mixed. This study examined relationships between inflammatory biomarkers and symptoms in patients with gynecologic cancer compared to age-matched women with no cancer history (i.e., controls). Patients (n = 121) completed assessments before chemotherapy cycles 1, 3, and 6, and 6 and 12 months later. Controls (n = 105) completed assessments at similar timepoints. Changes in inflammation and symptomatology were evaluated using random-effects mixed models, and cross-sectional differences between patients and controls in inflammatory biomarkers and symptoms were evaluated using least squares means. Associations among inflammatory biomarkers and symptoms were evaluated using random-effects fluctuation mixed models. The results indicated that compared to controls, patients typically have higher inflammatory biomarkers (i.e., TNF-alpha, TNFR1, TNFR2, CRP, IL-1ra) and worse fatigue, depression, and sleep (ps < 0.05). Patients reported lower levels of baseline physical activity (p = 0.02) that became more similar to controls over time. Significant associations were observed between CRP, depression, and physical activity (ps < 0.05), but not between inflammation and other symptoms. The results suggest that inflammation may not play a significant role in fatigue or sleep disturbance among gynecologic cancer patients but may contribute to depression and physical inactivity.

Change in Neurocognitive Performance Among Patients with Non-Hodgkin Lymphoma in the First Year after Chimeric Antigen Receptor T Cell Therapy.

The success of chimeric antigen receptor (CAR) T cell therapy in treating patients with relapsed/refractory hematologic malignancies is leading to a growing number of survivors treated with this regimen. To our knowledge, no previous studies have examined neurocognitive performance in adult CAR T cell therapy recipients, despite high rates of neurotoxicity and cytokine release syndrome (CRS) in the acute treatment period. This study examined changes in neurocognitive performance in the first year after CAR T cell therapy for non-Hodgkin lymphoma (NHL). Putative risk factors for worsening neurocognitive performance (eg, neurotoxicity, CRS) were explored as well. Neurocognition was assessed before initiation of CAR T cell therapy and at 30, 90, and 360 days post-treatment. Clinical variables were abstracted from medical records. Mixed models were used to examine change in total neurocognitive performance (TNP) and cognitive domains (ie, attention, executive function, verbal ability, immediate and delayed memory, and visuospatial abilities). Among 117 participants (mean age, 61 years; 62% male), TNP and executive function declined slightly on average from baseline to day 90 and then improved from day 90 to day 360 (P < .04). Small but significant linear declines in visuospatial ability on average were also observed over time (P = .03). Patients who had 4 or more lines of previous therapy and those with worse neurotoxicity (but not CRS) demonstrated worse TNP. CAR T cell therapy recipients reported transient or persistent deterioration in several cognitive domains, although changes were slight. These findings may be useful when educating future patients on what to expect when receiving CAR T cell therapy.

Meta-Analysis of Quality of Life in Cancer Patients Treated With Immune Checkpoint Inhibitors.

BACKGROUND: Trials of immune checkpoint inhibitors (ICIs) have published patient-reported quality of life (QOL), but the size and heterogeneity of this literature can make patient education difficult. This meta-analysis aimed to describe change in QOL and symptomatology in patients receiving ICIs for cancer. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, databases were searched through November 2019 for articles or abstracts of prospective, original studies reporting longitudinal QOL in adult cancer patients treated with ICIs. The prespecified primary outcomes were change in global QOL among patients treated with ICIs and difference in change since baseline in global QOL between patients treated with ICI vs non-ICI active treatment. Secondary outcomes included physical functioning and symptomatology. All statistical tests were 2-sided. RESULTS: Of 20 323 publications, 26 met inclusion criteria. Global QOL did not change over time in patients treated with ICIs (k = 26, n = 6974; P = .19). Larger improvements in global QOL was observed in patients receiving ICI vs non-ICI regimens (k = 16, ICI: n = 3588; non-ICI: n = 2948; P < .001). Physical functioning did not change in patients treated with ICIs (k = 14, n = 3169; P = .47); there were no differences in mean change between ICI vs non-ICI regimens (k = 11, n = 4630; P = .94). Regarding symptoms, appetite loss, insomnia, and pain severity decreased, but dyspnea severity increased in patients treated with ICIs (k = 14, n = 3243-3499; P < .001). Insomnia severity was higher in patients treated with ICIs than non-ICI regimens (k = 11, n = 4791; P < .001). CONCLUSIONS: This study is among the first to quantitatively summarize QOL in patients treated with ICIs. Findings suggest ICI recipients report no change in global QOL and higher QOL than patients treated with non-ICI regimens.

Acute patient-reported outcomes in B-cell malignancies treated with axicabtagene ciloleucel.

Chimeric antigen receptor T-cell therapy with axicabtagene ciloleucel (axi-cel) has considerably improved survival in adults with relapsed/refractory large B-cell lymphoma. This study reports patient-reported outcomes (PROs) such as quality of life (QOL) and toxicity in the first 90 days after treatment. Hematologic cancer patients treated with axi-cel (N = 103, mean age = 61, 39% female) completed SF-36 or PROMIS-29 QOL questionnaires prior to treatment and 90 days after. PRO-Common Terminology Criteria for Adverse Events toxicity items were completed by patients at baseline and 14, 30, 60, and 90 days after treatment. Mixed models examined change in PROs over time. From preinfusion to 90 days later, patients reported improvements in physical functioning, pain, and fatigue (ps < 0.01), but worsening of anxiety (p = 0.02). Patient-reported toxicities worsened by day 14 with improvement thereafter. The five most severe symptoms at day 14 included fatigue, decreased appetite, dry mouth, diarrhea frequency, and problems with concentration. Results indicate improvement in some domains of QOL over time with transient patient-reported toxicities.

Lagged Relationships Among Chemotherapy-Induced Peripheral Neuropathy, Sleep Quality, and Physical Activity During and After Chemotherapy.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is well-documented and can become chronic for up to a third of patients. CIPN management is hampered by limited pharmacological options. Thus, identifying modifiable behaviors that influence CIPN may help inform future interventions. PURPOSE: The purpose of the current study was to examine bidirectional relationships between sleep quality, physical activity, and CIPN during and after chemotherapy. METHODS: Participants were 138 women with gynecologic cancer (M age = 61, 94% white, 96% non-Hispanic), collected as part of an ongoing study. Assessments occurred at postcycle 1, postcycle 6, and 6- and 12-month postchemotherapy. CIPN (EORTC-CIPN20), sleep quality (PSQI), and physical activity (IPAQ) were assessed via self-report. Objective physical activity was assessed via wrist actigraphy. Latent change score models were used to examine lagged relationships between CIPN, sleep quality, and physical activity pairs. RESULTS: Over the study period, sleep quality was found to contribute to CIPN (p = .001), but not the reverse (p > .05). Bidirectional relationships were observed between CIPN and both objective and subjective walking (ps ≤ .001). Illustrations of these relationships showed that patients with less CIPN early in treatment demonstrate more substantial increases in walking over time, while those with higher CIPN demonstrate more consistent levels of walking during and after treatment. CONCLUSIONS: These findings suggest that worse sleep quality and lower walking levels may contribute to the course and maintenance of CIPN. Future investigation should evaluate the impact of early interventions aimed at improving sleep quality and encouraging physical activity in patients treated with chemotherapy.

A longitudinal examination of associations between age and chemotherapy-induced peripheral neuropathy in patients with gynecologic cancer.

OBJECTIVE: Increasing age has been associated with higher risk of chemotherapy-related toxicities, often resulting in treatment disruptions or discontinuations. Age has also been evaluated as a potential risk factor for chemotherapy-induced peripheral neuropathy (CIPN), but current understanding of recovery from CIPN in older adults after treatment is limited. The goal of the current study was to: 1) evaluate longitudinal change in patient-reported CIPN symptoms from the start of chemotherapy to one year post-chemotherapy; and 2) examine treatment modifications in older (≥65 years) and younger patients (<65 years). METHODS: As part of a larger ongoing study, gynecologic cancer patients (n = 90) treated with cytoxic chemotherapy reported their CIPN symptoms via the EORTC-CIPN20 three times during active treatment and at 6 and 12 months post-treatment. Medical record reviews were conducted to abstract clinical information during active treatment. RESULTS: Piecewise mixed models revealed that older and younger patients reported similar increases in CIPN during the active treatment phase. However, older patients did not recover from CIPN after treatment completion, whereas younger patients exhibited significant declines in CIPN symptoms post-treatment. No age differences were observed in the presence of provider-recorded sensory neuropathy and pain; neuropathy-related treatment delays, changes in chemotherapy dose, regimen, or discontinuations; or falls (all p-values > 0.05). CONCLUSIONS: Results from the current study indicate that older adults are at higher risk for chronic CIPN. Older survivors may require additional education and treatment for chronic CIPN symptoms. Additional studies are needed to explore novel interventions to manage chronic CIPN in older cancer survivors.

An assay to compare the infectivity of Mycobacterium tuberculosis isolates based on aerosol infection of guinea pigs and assessment of bacteriology.

The aim of this study was to establish an assay to compare Mycobacterium tuberculosis strains, and cells grown under different growth conditions, in terms of their ability to cause a lung infection and disseminate to the spleen. M. tuberculosis strains H37Rv, Erdman, South Indian (TMC120, SI) and H37Rv cells grown aerobically or under low oxygen/iron limitation in a chemostat were assayed for infectivity. Groups of 8 animals were challenged with 3 different doses of each strain. Lung and spleen bacteriology was assessed at 16 days post-infection for all strains. Bacteriology and lung pathology at day 56 was studied for H37Rv, Erdman and SI. Strains H37Rv and Erdman had a statistically significantly higher pathogenic potential than SI and this was confirmed by analysis of lung pathology performed at 8 weeks post-infection, although the Erdman strain caused more extensive caseation without calcification and little encapsulation. The model could discriminate between cells grown under different growth conditions; low-oxygen/iron-limited cells had a significantly higher infectivity than those grown aerobically. This study presents a quick and reliable method for comparing with statistical confidence, the pathogenic potential of M. tuberculosis strains and the impact of in vitro growth conditions on the infectivity of M. tuberculosis in vivo.

The influence of reduced oxygen availability on pathogenicity and gene expression in Mycobacterium tuberculosis.

We investigated how Mycobacterium tuberculosis responded to a reduced oxygen tension in terms of its pathogenicity and gene expression by growing cells under either aerobic or low-oxygen conditions in chemostat culture. The chemostat enabled us to control and vary the oxygen tension independently of other environmental parameters, so that true cause-and-effect relationships of reduced oxygen availability could be established. Cells grown under low oxygen were more pathogenic for guinea pigs than those grown aerobically. The effect of reduced oxygen on global gene expression was determined using DNA microarray. Spearman rank correlation confirmed that microarray expression profiles were highly reproducible between repeat cultures. Using microarray analysis we have identified genes that respond to a low-oxygen environment without the influence of other parameters such as nutrient depletion. Some of these genes appear to be involved in the biosynthesis of cell wall precursors and their induction may have contributed to increased infectivity in the guinea pig. This study has shown that a combination of chemostat culture and microarray presents a biologically robust and statistically reliable experimental approach for studying the effect of relevant and specific environmental stimuli on mycobacterial virulence and gene expression.

Stationary phase gene expression of Mycobacterium tuberculosis following a progressive nutrient depletion: a model for persistent organisms?

The majority of individuals infected with TB develop a latent infection, in which organisms survive within the body while evading the host immune system. Such persistent bacilli are capable of surviving several months of combinatorial antibiotic treatment. Evidence suggests that stationary phase bacteria adapt to increase their tolerance to environmental stresses. We have developed a unique in vitro model of dormancy based on the characterization of a single, large volume fermenter culture of M. tuberculosis, as it adapts to stationary phase. Cells are maintained in controlled and defined aerobic conditions (50% dissolved oxygen tension), using probes that measure dissolved oxygen tension, temperature, and pH. Microarray analysis has been used in conjunction with viability and nutrient depletion assays to dissect differential gene expression. Following exponential phase growth the gradual depletion of glucose/glycerol resulted in a small population of survivors that were characterized for periods in excess of 100 days. Bacilli adapting to nutrient depletion displayed characteristics associated with persistence in vivo, including entry into a non-replicative state and the up-regulation of genes involved in beta-oxidation of fatty acids and virulence. A reduced population of non-replicating bacilli went on to adapt sufficiently to re-initiate cellular division.

In vitro gene expression dissected: chemostat surgery for mycobacterium tuberculosis.

A unique approach, combining defined and reproducible in vitro models with DNA microarrays, has been developed to study environmental modulation of mycobacterial gene expression. The gene expression profiles of samples of Mycobacterium tuberculosis, from independent chemostat cultures grown under defined and reproducible conditions, were found to be highly correlated. This approach is now being used to study the effect of relevant stimuli, such as limited oxygen availability, on mycobacterial gene expression. A modification of the chemostat culture system, enabling large-volume controlled batch culture, has been developed to study starvation survival. Cultures of M. tuberculosis have been maintained under nutrient-starved conditions for extended periods, with 10(6) - 10(7) bacilli surviving in a culturable state after 100 days. The design of the culture system has made it possible to control the environment and collect multiple time-course samples to study patterns of gene expression. These studies demonstrate that it is possible to perform long-term studies and obtain reproducible expression data using controlled and defined in vitro models.