Neurotoxic complications of chemotherapy in patients with cancer: clinical signs and optimal management

Role of oxidative stress in oxaliplatin-induced enteric neuropathy and colonic dysmotility in mice

BACKGROUND AND PURPOSE

Oxaliplatin is a platinum-based chemotherapeutic drug used as a first-line therapy for colorectal cancer. However, its use is associated with severe gastrointestinal side-effects resulting in dose limitations and/or cessation of treatment. In this study, we tested whether oxidative stress, caused by chronic oxaliplatin treatment, induces enteric neuronal damage and colonic dysmotility.

EXPERIMENTAL APPROACH

Oxaliplatin (3 mg·kg^-1 per day) was administered in vivo to Balb/c mice intraperitoneally three times a week. The distal colon was collected at day 14 of treatment. Immunohistochemistry was performed in wholemount preparations of submucosal and myenteric ganglia. Neuromuscular transmission was studied by intracellular electrophysiology. Circular muscle tone was studied by force transducers. Colon propulsive activity studied in organ bath experiments and faeces were collected to measure water content.

KEY RESULTS

Chronic in vivo oxaliplatin treatment resulted in increased formation of reactive oxygen species (O₂ -), nitration of proteins, mitochondrial membrane depolarisation resulting in the release of cytochrome c, loss of neurons, increased inducible NOS expression and apoptosis in both the submucosal and myenteric plexuses of the colon. Oxaliplatin treatment enhanced NO-mediated inhibitory junction potentials and altered the response of circular muscles to the NO donor, sodium nitroprusside. It also reduced the frequency of colonic migrating motor complexes and decreased circular muscle tone, effects reversed by the NO synthase inhibitor, Nω-Nitro-L-arginine.

CONCLUSION AND IMPLICATIONS

Our study is the first to provide evidence that oxidative stress is a key player in enteric neuropathy and colonic dysmotility leading to symptoms of chronic constipation observed in oxaliplatin-treated mice.

Electrical stimulation inhibits cytosine arabinoside-induced neuronal death by preventing apoptosis in dorsal root ganglion neurons

The current study aimed to investigate whether electrical stimulation could prevent apoptotic neuronal cell death during treatment with cytosine arabinoside (ara-C). From in-vitro experiments, the effects of electrical stimulation were assessed on neurite fragmentation and neuronal cell death in ara-C-treated dorsal root ganglion (DRG) explants. Ara-C treatment increased neurite fragmentation and neuronal cell death in DRG explants and activated caspase-3 by cleaving it, which could induce apoptosis. Electrical stimulation can significantly reduce neurite fragmentation and neuronal cell death compared with nonelectrically stimulated groups. Furthermore, electrical stimulation inhibited caspase-3 activation and reduced apoptotic neuronal death in DRG explants. It was suggested that the neuroprotective effect of electrical stimulation is likely mediated by the inhibition of caspase-3 activation and therefore the inhibition of apoptosis following ara-C treatment.

Chemotherapy-Induced Constipation and Diarrhea: Pathophysiology, Current and Emerging Treatments

Gastrointestinal (GI) side-effects of chemotherapy are a debilitating and often overlooked clinical hurdle in cancer management. Chemotherapy-induced constipation (CIC) and Diarrhea (CID) present a constant challenge in the efficient and tolerable treatment of cancer and are amongst the primary contributors to dose reductions, delays and cessation of treatment. Although prevalence of CIC is hard to estimate, it is believed to affect approximately 16% of cancer patients, whilst incidence of CID has been estimated to be as high as 80%. Despite this, the underlying mechanisms of both CID and CIC remain unclear, but are believed to result from a combination of intersecting mechanisms including inflammation, secretory dysfunctions, GI dysmotility and alterations in GI innervation. Current treatments for CIC and CID aim to reduce the severity of symptoms rather than combating the pathophysiological mechanisms of dysfunction, and often result in worsening of already chronic GI symptoms or trigger the onset of a plethora of other side-effects including respiratory depression, uneven heartbeat, seizures, and neurotoxicity. Emerging treatments including those targeting the enteric nervous system present promising avenues to alleviate CID and CIC. Identification of potential targets for novel therapies to alleviate chemotherapy-induced toxicity is essential to improve clinical outcomes and quality of life amongst cancer sufferers.

Prophylactic treatment with the tricyclic antidepressant desipramine prevents development of paclitaxel-induced neuropathic pain through activation of endogenous analgesic systems

Neuropathic pain impacts approximately 3-4.5% of the global population and remains an unresolved health problem. The management of neuropathic pain has two distinct goals-prevention of development and control of established neuropathic pain. We examined the impact of both prophylactic and therapeutic treatments with the tricyclic antidepressant desipramine on the development and maintenance of toxic neuropathic pain induced by the chemotherapeutic agent paclitaxel. We also investigated the involvement of endogenous analgesic (i.e., endogenous opioid and endocannabinoid) systems in the antinociceptive actions of desipramine in these two distinct phases of neuropathic pain. Chronic subcutaneous infusion of desipramine via osmotic pumps suppressed both the development and maintenance of paclitaxel-induced neuropathic pain. However, only prophylactic desipramine treatment blocked the development of neuropathic pain throughout the three month observation interval; neuropathic pain did not return. The opioid receptor antagonist naloxone blocked the antinociceptive effects of both prophylactic and therapeutic desipramine treatments throughout the entire timecourse of desipramine-induced antinociception. By contrast, cannabinoid CB₁ and CB₂ receptor antagonists partially attenuated the antinociceptive actions of desipramine in a manner that was restricted to the development phase of paclitaxel-induced neuropathic pain only. Paclitaxel decreased cell viability in TMD231 tumor cells in an MTT assay in vitro. Notably, desipramine (1nM-1μM) alone did not alter tumor cell viability and did not prevent the cytotoxic effects of paclitaxel under identical conditions. The highest concentration of desipramine (10μM) reduced tumor cell viability alone and enhanced the cytotoxic effects of paclitaxel. Our study identifies a previously unrecognized preemptive analgesic strategy that prevents development of paclitaxel-induced neuropathic pain, and also dissects receptor mechanisms underlying desipramine-induced antinociceptive effects. This information may be applied to improve current therapeutic strategies with the goal of preventing and managing neuropathic pain induced by chemotherapeutic treatment.

Clinical trials in pediatric neuro-oncology: what is missing and how we can improve

Brain tumors are the most common solid tumor in childhood, yet outcomes vary dramatically. High-grade gliomas have dismal outcomes with poor survival. By contrast, low-grade gliomas, have high survival rates, but children suffer from morbidity of tumor burden and therapy-associated side effects. In this article, we discuss how current trial designs often miss the opportunity to include end points beyond tumor response and thus fail to offer complete assessments of therapeutic approaches. Quality of life, neurocognitive function and neurofunctional deficits need to be considered when assessing overall success of a therapy. Herein, we identify specific end points that should be included in the interpretation of clinical trial results and accordingly, offer a more comprehensive approach to treatment decision-making.

Impaired Brain Dopamine and Serotonin Release and Uptake in Wistar Rats Following Treatment with Carboplatin

Chemotherapy-induced cognitive impairment, known also as “chemobrain”, is a medical complication of cancer treatment that is characterized by a general decline in cognition affecting visual and verbal memory, attention, complex problem solving skills, and motor function. It is estimated that one-third of patients who undergo chemotherapy treatment will experience cognitive impairment. Alterations in the release and uptake of dopamine and serotonin, central nervous system neurotransmitters that play important roles in cognition, could potentially contribute to impaired intellectual performance in those impacted by chemobrain. To investigate how chemotherapy treatment affects these systems, fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes was used to measure dopamine and serotonin release and uptake in coronal brain slices containing the striatum and dorsal raphe nucleus, respectively. Measurements were taken from rats treated weekly with selected doses of carboplatin and from control rats treated with saline. Modeling the stimulated dopamine release plots revealed an impairment of dopamine release per stimulus pulse (80% of saline control at 5 mg/kg and 58% at 20 mg/kg) after 4 weeks of carboplatin treatment. Moreover, V_max, the maximum uptake rate of dopamine, was also decreased (55% of saline control at 5 mg/kg and 57% at 20 mg/kg). Nevertheless, overall dopamine content, measured in striatal brain lysates by high performance liquid chromatography, and reserve pool dopamine, measured by FSCV after pharmacological manipulation, did not significantly change, suggesting that chemotherapy treatment selectively impairs the dopamine release and uptake processes. Similarly, serotonin release upon electrical stimulation was impaired (45% of saline control at 20 mg/kg). Measurements of spatial learning discrimination were taken throughout the treatment period and carboplatin was found to alter cognition. These studies support the need for additional neurochemical and behavioral analyses to identify the underlying mechanisms of chemotherapy-induced cognitive disorders.

Chemotherapy-induced neurotoxicity in pediatric solid non-CNS tumor patients: An update on current state of research and recommended future directions

Neurocognitive sequelae are known to be induced by cranial radiotherapy and central-nervous-system-directed chemotherapy in childhood Acute Lymphoblastic Leukemia (ALL) and brain tumor patients. However, less evidence exists for solid non-CNS-tumor patients. To get a better understanding of the potential neurotoxic mechanisms of non-CNS-directed chemotherapy during childhood, we performed a comprehensive literature review of this topic. Here, we provide an overview of preclinical and clinical studies investigating neurotoxicity associated with chemotherapy in the treatment of pediatric solid non-CNS tumors. Research to date suggests that chemotherapy has deleterious biological and psychological effects, with animal studies demonstrating histological evidence for neurotoxic effects of specific agents and human studies demonstrating acute neurotoxicity. Although the existing literature suggests potential neurotoxicity throughout neurodevelopment, research into the long-term neurocognitive sequelae in survivors of non-CNS cancers remains limited. Therefore, we stress the critical need for neurodevelopmental focused research in children who are treated for solid non-CNS tumors, since they are at risk for potential neurocognitive impairment.

Late Effects of Treatment of Pediatric Central Nervous System Tumors

Central nervous system tumors represent the most common solid malignancy in childhood. Improvement in treatment approaches have led to a significant increase in survival rates, with over 70% of children now surviving beyond 5 years. As more and more children with CNS tumors have longer survival times, it is important to be aware of the long-term morbidities caused not only by the tumor itself but also by tumor treatment. The most common side effects including poor neurocognition, endocrine dysfunction, neurological and vascular late effects, as well as secondary malignancies, are discussed within this article.

Neurotoxicity to DRG neurons varies between rodent strains treated with cisplatin and bortezomib

Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose limiting side effect that can lead to long-term morbidity. Approximately one-third of patients receiving chemotherapy with taxanes, vinca alkaloids, platinum compounds or proteasome inhibitors develop this toxic side effect. It is not possible to predict who will get CIPN, however, genetic susceptibility may play a role. We explored this hypothesis using an established in vitro dorsal root ganglia neurite outgrowth (DRG-NOG) assay to assess possible genetic influences for cisplatin- and bortezomib-induced neurotoxicity. Almost all previous in vitro studies have used rats or mice. We compared DRG-NOG between four genetically defined, inbred mouse strains (C57BL/6J, DBA/2J, BALB/cJ, and C3H/HeJ) and one rat strain (Sprague Dawley). Our studies found differences in cisplatin and bortezomib-induced neurotoxicity between mouse and rat strains and between the different mouse strains. C57BL/6J and Balb/cJ DRG-NOG was more sensitive to cisplatin than DBA/2J and C3H/HeJ DRG-NOG, and all mouse strains were more sensitive to cisplatin than rat. Bortezomib induced a biphasic dose response in DBA/2J and C3H/H3J mice. C57BL/6J DRG-NOG was most sensitive and Balb/cJ DRG-NOG was least sensitive to bortezomib. Our animal data supports the hypothesis that genetic background may play a role in CIPN and care must be taken when rodent models are used to better understand the contribution of genetics in patient susceptibility to CIPN.

Effect of Vitamin E on Oxaliplatin-induced Peripheral Neuropathy Prevention: A Randomized Controlled Trial

BACKGROUND

Peripheral neuropathy is one of the most important limitations of oxaliplatin base regimen, which is the standard for the treatment of colorectal cancer. Evidence has shown that Vitamin E may be protective in chemotherapy-induced peripheral neuropathy. The aim of this study is to evaluate the effect of Vitamin E administration on prevention of oxaliplatin-induced peripheral neuropathy in patients with colorectal cancer.

METHODS

This was a prospective randomized, controlled clinical trial. Patients with colorectal cancer and scheduled to receive oxaliplatin-based regimens were enrolled in this study. Enrolled patients were randomized into two groups. The first group received Vitamin E at a dose of 400 mg daily and the second group observed, until after the sixth course of the oxaliplatin regimen. For oxaliplatin-induced peripheral neuropathy assessment, we used the symptom experience diary questionnaire that completed at baseline and after the sixth course of chemotherapy. Only patients with a score of zero at baseline were eligible for this study.

RESULTS

Thirty-two patients were randomized to the Vitamin E group and 33 to the control group. There was no difference in the mean peripheral neuropathy score changes (after - before) between two groups, after sixth course of the oxaliplatin base regimen (mean difference [after - before] of Vitamin E group = 6.37 ± 2.85, control group = 6.57 ± 2.94; P = 0.78). Peripheral neuropathy scores were significantly increased after intervention compared with a base line in each group (P < 0.001).

CONCLUSIONS

The results from this current trial demonstrate a lack of benefit for Vitamin E in preventing oxaliplatin-induced peripheral neuropathy.

Pain in cancer survivors

Cancer and its treatment exert a heavy psychological and physical toll. Of the myriad symptoms which result, pain is common, encountered in between 30% and 60% of cancer survivors. Pain in cancer survivors is a major and growing problem, impeding the recovery and rehabilitation of patients who have beaten cancer and negatively impacting on cancer patients' quality of life, work prospects and mental health. Persistent pain in cancer survivors remains challenging to treat successfully. Pain can arise both due to the underlying disease and the various treatments the patient has been subjected to. Chemotherapy causes painful chemotherapy-induced peripheral neuropathy (CIPN), radiotherapy can produce late effect radiation toxicity and surgery may lead to the development of persistent post-surgical pain syndromes. This review explores a selection of the common causes of persistent pain in cancer survivors, detailing our current understanding of the pathophysiology and outlining both the clinical manifestations of individual pain states and the treatment options available.

Bilateral Blindness Following Chemoradiation for Locally Advanced Oropharyngeal Carcinoma

Wernicke's encephalopathy is a life-threatening neurologic complication of thiamine deficiency. Though the presentation of symptoms can vary widely, the classical triad is founded on ophthalmoplegia, alteration of mental status, and gait disturbance. We describe a case of Wernicke's encephalopathy in an oncology patient shortly after concurrent 5-fluorouracil, carboplatin, and radiotherapy for locally advanced oropharyngeal cancer, presenting as complete bilateral blindness, ataxia, nystagmus, and confusion. Thiamine was given based on clinical suspicion and rapid improvement of clinical findings occurred. An MRI performed later supported the diagnosis of Wernicke's encephalopathy. A multifactorial etiology of thiamine deficiency from nutritional deficits and neurotoxic effects of chemotherapy are hypothesized.

Cancer-treatment-induced neurotoxicity--focus on newer treatments

Neurotoxicity caused by traditional chemotherapy and radiotherapy is widely recognized in patients with cancer. The adverse effects of newer therapeutics, such as biological and immunotherapeutic agents, are less well established, and are associated with considerable neurotoxicity in the central and peripheral nervous systems. This Review addresses the main neurotoxicities of cancer treatment with a focus on the newer therapeutics. Recognition of these patterns of toxicity is important because drug discontinuation or dose adjustment might prevent further neurological injury. Knowledge of these toxicities also helps to differentiate treatment-related symptoms from progression of cancer or its involvement of the nervous system. Familiarity with the neurological syndromes associated with cancer treatments enables clinicians to use the appropriate treatment for the underlying malignancy while minimizing the risk of neurological damage, which might preserve patients' quality of life.

Spinal Nerve Root Enhancement on MRI Scans in Children: A Review

Spinal nerve root enhancement in pediatric patients is generally nonspecific, and clinical and laboratory correlation is essential. Nerve root enhancement indicates lack of integrity of the blood-nerve barrier. In this review, we will present a range of pediatric conditions that can present with spinal nerve root enhancement including inflammatory, infectious, hereditary, and neoplastic causes. Familiarity with the various pathologic entities associated with spinal nerve root enhancement is important for a concise differential diagnosis in the appropriate clinical setting. This will avoid unnecessary additional investigations.

Survivors of gynecologic malignancies: impact of treatment on health and well-being

PURPOSE

While overall survival from gynecologic malignancies has greatly improved over the last three decades, required treatments can lead to multiple health issues for survivors. Our objective was to identify health concerns that gynecologic cancer survivors face.

METHODS

A systematic, stratified sample of women with gynecologic malignancies was surveyed for 18 health issues occurring before, during, or after treatment. The impact of clinical features and treatment modality on health issues was assessed through multivariate logistic regression models.

RESULTS

Of 2,546 surveys mailed, 622 were not received by eligible subjects secondary to invalid address, incorrect diagnosis, or death. Thus, 1924 survivors potentially received surveys. Of the 1,029 surveys (53.5%) completed, median age was 59 years; diagnoses included 29% cervical, 26% endometrial, 26% ovarian/primary peritoneal/fallopian tube, 12.1% vulvar, and 5.4% vaginal cancers. The most frequently reported health issues included fatigue (60.6%), sleep disturbance (54.9%), urinary difficulties (50.9%), sexual dysfunction (48.4%), neurologic issues (45.4%), bowel complaints (42.0%), depression (41.3%), and memory problems (41.2%). These rankings were consistent with patients' self-reported rankings of "highest impact" personal issues. After controlling for demographic and clinical variables, multivariate analyses revealed that treatment modality impacted the odds of experiencing a given health issue.

CONCLUSIONS

Our study demonstrates that gynecologic cancer survivors experience a high frequency of health conditions and highlights the association between treatment modality and specific health concerns.

IMPLICATIONS FOR CANCER SURVIVORS

The study findings highlight the multiple health concerns experienced by gynecologic cancer survivors and suggest the potential for developing interventions to mitigate these concerns in survivorship.

Measuring Therapy-Induced Peripheral Neuropathy: Preliminary Development and Validation of the Treatment-Induced Neuropathy Assessment Scale

Various sensory and motor effects are associated with cancer treatment-induced peripheral neuropathy. The current method for capturing the multifaceted nature of neuropathy includes a combination of objective tests, clinician evaluation, and subjective patient report, an approach that is often not logistically feasible, especially for multisite trials. We report the performance of a brief yet comprehensive, easily administered measure, the Treatment-Induced Neuropathy Assessment Scale (TNAS), for assessing the severity and course of neuropathy across various cancer treatments. Data were derived from 4 longitudinal or cross-sectional patient cohorts (N = 573). Patients with multiple myeloma treated primarily with bortezomib and patients with colorectal cancer receiving oxaliplatin evaluated candidate items. Cognitive debriefing showed that all items were easy to understand, and this preliminary TNAS demonstrated reliability, validity, and sensitivity. Numbness/tingling was the most severe item, regardless of therapeutic agent. Although numbness and general pain were moderately correlated, patients perceived them as distinct. Most TNAS items were more severe at follow-up, demonstrating the sensitivity of the instrument to accumulating dose. The TNAS will be refined with further patient input, with final psychometric evaluation conducted in a new patient sample receiving treatments known to be associated with peripheral neuropathy. The nonpainful component of neuropathy may be more disabling than the pain component.

PERSPECTIVE

Our data suggest that the nonpainful components of neuropathy may be more disabling than the pain component during cancer treatment. Here we report data on sensory and motor symptoms reported by patients receiving neurotoxic cancer therapy, and we detail the development of a neuropathy assessment scale that follows regulatory guidance for patient-reported outcomes.

Modifying chemotherapeutic management of a patient with Burkitt's lymphoma and pre-existing motor neurone disease

WHAT IS KNOWN AND OBJECTIVE

Intensive chemotherapy for treatment of Burkitt's lymphoma (BL) - a high-grade lymphoproliferative disorder (LPD) - can cause neurotoxicity. An association between motor neurone disease (MND) and LPDs has previously been described, but there is a lack of recommendations available to guide management of such patients. This report aims to describe suitable management of BL in a patient with MND.

CASE DESCRIPTION

A 66-year-old woman with a history of MND affecting her limbs was diagnosed with bulky, extranodal, high-risk gastric BL. Standard chemotherapy is with multiple non-cross-resistant cytotoxic agents. To avoid exacerbation of neuropathy, six cycles of a modified regimen was planned, aiming to minimize exposure to the most neurotoxic agents. A PET-FDG-negative remission was obtained at 12 months, without the signs of central neurotoxicity, peripheral neuropathy or muscle weakness.

WHAT IS NEW AND CONCLUSION

High-intensity chemotherapy, minimizing known neurotoxic agents, was delivered safely and effectively in a patient with BL and pre-existing MND. More case descriptions are required to guide management decisions.

Severe fludarabine neurotoxicity after reduced intensity conditioning regimen to allogeneic hematopoietic stem cell transplantation: a case report

We present a case of severe, irreversible neurotoxicity in a 55-year-old-patient with myelofibrosis undergoing hematopoietic stem cell transplantation following a reduced intensity conditioning including fludarabine. The patient developed progressive sensory-motor, visual and consciousness disturbances, eventually leading to death. MRI imaging pattern was unique and attributable to fludarabine neurotoxicity.

Ghrelin Prevents Cisplatin-Induced Testicular Damage by Facilitating Repair of DNA Double Strand Breaks Through Activation of p53 in Mice

Cisplatin administration induces DNA damage resulting in germ cell apoptosis and subsequent testicular atrophy. Although 50 percent of male cancer patients receiving cisplatin-based chemotherapy develop long-term secondary infertility, medical treatment to prevent spermatogenic failure after chemotherapy is not available. Under normal conditions, testicular p53 promotes cell cycle arrest, which allows time for DNA repair and reshuffling during meiosis. However, its role in the setting of cisplatin-induced infertility has not been studied. Ghrelin administration ameliorates the spermatogenic failure that follows cisplatin administration in mice, but the mechanisms mediating these effects have not been well established. The aim of the current study was to characterize the mechanisms of ghrelin and p53 action in the testis after cisplatin-induced testicular damage. Here we show that cisplatin induces germ cell damage through inhibition of p53-dependent DNA repair mechanisms involving gamma-H2AX and ataxia telangiectasia mutated protein kinase. As a result, testicular weight and sperm count and motility were decreased with an associated increase in sperm DNA damage. Ghrelin administration prevented these sequelae by restoring the normal expression of gamma-H2AX, ataxia telangiectasia mutated, and p53, which in turn allows repair of DNA double stranded breaks. In conclusion, these findings indicate that ghrelin has the potential to prevent or diminish infertility caused by cisplatin and other chemotherapeutic agents by restoring p53-dependent DNA repair mechanisms.

The long-term impact of oxaliplatin chemotherapy on rodent cognition and peripheral neuropathy

Chemotherapy treatment is associated with cognitive dysfunction in cancer survivors after treatment completion. The duration of these impairments is unclear. Therefore this paper aims to evaluate the lasting impact of varying doses of the chemotherapy oxaliplatin (OX) on cognition and peripheral neuropathy. In Experiment 1 rats were treated once a week for 3 weeks with either physiological saline (control) or 6 mg/kg OX i.p. and were assessed for peripheral neuropathy, using von Frey filaments, and cognitive function, using novel object and location recognition, up to 2 weeks after treatment completion. For Experiment 2 rats received 3 weekly i.p. injections of either physiological saline (control), 0.6 mg/kg, 2mg/kg or 6 mg/kg OX and assessed for peripheral neuropathy and cognitive function up to 11 months after treatment completion. Systemic OX treatment induced lasting effects on cognitive function at 11 months after treatment, and peripheral neuropathy at 1 month after treatment and these were dose dependent; higher doses of OX resulted in worse cognitive outcomes and more severe peripheral neuropathy.

Platinum-induced neurotoxicity and preventive strategies: past, present, and future

Neurotoxicity is a burdensome side effect of platinum-based chemotherapy that prevents administration of the full efficacious dosage and often leads to treatment withdrawal. Peripheral sensory neurotoxicity varies from paresthesia in fingers to ataxic gait, which might be transient or irreversible. Because the number of patients being treated with these neurotoxic agents is still increasing, the need for understanding the pathogenesis of this dramatic side effect is critical. Platinum derivatives, such as cisplatin and carboplatin, harm mainly peripheral nerves and dorsal root ganglia neurons, possibly because of progressive DNA-adduct accumulation and inhibition of DNA repair pathways (e.g., extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase/stress-activated protein kinase, and p38 mitogen-activated protein kinass), which finally mediate apoptosis. Oxaliplatin, with a completely different pharmacokinetic profile, may also alter calcium-sensitive voltage-gated sodium channel kinetics through a calcium ion immobilization by oxalate residue as a calcium chelator and cause acute neurotoxicity. Polymorphisms in several genes, such as voltage-gated sodium channel genes or genes affecting the activity of pivotal metal transporters (e.g., organic cation transporters, organic cation/carnitine transporters, and some metal transporters, such as the copper transporters, and multidrug resistance-associated proteins), can also influence drug neurotoxicity and treatment response. However, most pharmacogenetics studies need to be elucidated by robust evidence. There are supportive reports about the effectiveness of several neuroprotective agents (e.g., vitamin E, glutathione, amifostine, xaliproden, and venlafaxine), but dose adjustment and/or drug withdrawal seem to be the most frequently used methods in the management of platinum-induced peripheral neurotoxicity. To develop alternative options in the treatment of platinum-induced neuropathy, studies on in vitro models and appropriate trials planning should be integrated into the future design of neuroprotective strategies to find the best patient-oriented solution.

Self-reported memory problems in adult-onset cancer survivors: effects of cardiovascular disease and insomnia

BACKGROUND

Cancer and its treatments can deleteriously affect memory. Cardiac function and insomnia can exacerbate memory problems.

OBJECTIVE

To examine the relationships among cardiovascular disease, insomnia, and self-reported memory problems (SRMP) in adult-onset cancer survivors.

METHODS

We included data from participants (41-64 year-old) of the 2007-2008 National Health and Nutrition Examination Survey, a nationally representative probability sample of the civilian, non-institutionalized population of the US. We excluded participants with brain cancer/stroke history since these conditions are expected to cause cognitive problems. Using binary logistic regression, we determined the prevalence of SRMP relative to cardiac problems and insomnia by weighting our results proportionally. We adjusted for predictors of memory problems: age, sex, race, education and general health.

RESULTS

The sample included 2289 adults (49% females), 9% with a cancer history. The results pertain only to cancer survivors. Those with insomnia were 16 times as likely to have SRMP. Only insomnia symptoms (OR, 15.74; 95% CI, 1.73-143.30; p < 0.01) significantly predicted SRMP, uniquely explaining 12% of the variance. Insomnia accounted for 18.8% of the association between cardiac issues and SRMP, demonstrating mediation (Sobel p < 0.05). The large CI is a consequence of analyzing a sub-group of a subpopulation. Among participants without a cancer history, cardiovascular disease and insomnia were not associated with SRMP (p > 0.05).

LIMITATIONS

We could not determine severity and time-related changes in SRMP.

CONCLUSION

Likelihood of SRMP was higher in cancer survivors with a history of cardiovascular disease and insomnia symptoms. Future studies are needed to delineate the cardiac-insomnia-memory interrelationships.

Platinum-based chemotherapy: gastrointestinal immunomodulation and enteric nervous system toxicity

The efficacy of chemotherapeutic treatment of colorectal cancer is challenged by severe gastrointestinal side effects, which include nausea, vomiting, constipation, and diarrhea. These symptoms can persist long after the treatment has been ceased. An emerging concept is the ability of platinum-based drugs to stimulate immunity, which is in contrast to conventional chemotherapeutic agents that are immunosuppressive. Here, we review the immunomodulatory aspects of platinum-based anticancer chemotherapeutics and their impact on gastrointestinal innervation. Given the bidirectional communication between the enteric nervous system and gastrointestinal immune system; exploring the consequences of platinum-induced immunogenicity will facilitate better understanding of gut dysfunction caused by chemotherapeutic agents. We propose that the development of future successful chemotherapeutics should rely on targeting the mechanisms underlying long-term gastrointestinal side effects.

Redox biology in normal cells and cancer: restoring function of the redox/Fyn/c-Cbl pathway in cancer cells offers new approaches to cancer treatment

This review discusses a unique discovery path starting with novel findings on redox regulation of precursor cell and signaling pathway function and identification of a new mechanism by which relatively small changes in redox status can control entire signaling networks that regulate self-renewal, differentiation, and survival. The pathway central to this work, the redox/Fyn/c-Cbl (RFC) pathway, converts small increases in oxidative status to pan-activation of the c-Cbl ubiquitin ligase, which controls multiple receptors and other proteins of central importance in precursor cell and cancer cell function. Integration of work on the RFC pathway with attempts to understand how treatment with systemic chemotherapy causes neurological problems led to the discovery that glioblastomas (GBMs) and basal-like breast cancers (BLBCs) inhibit c-Cbl function through altered utilization of the cytoskeletal regulators Cool-1/βpix and Cdc42, respectively. Inhibition of these proteins to restore normal c-Cbl function suppresses cancer cell division, increases sensitivity to chemotherapy, disrupts tumor-initiating cell (TIC) activity in GBMs and BLBCs, controls multiple critical TIC regulators, and also allows targeting of non-TICs. Moreover, these manipulations do not increase chemosensitivity or suppress division of nontransformed cells. Restoration of normal c-Cbl function also allows more effective harnessing of estrogen receptor-α (ERα)-independent activities of tamoxifen to activate the RFC pathway and target ERα-negative cancer cells. Our work thus provides a discovery strategy that reveals mechanisms and therapeutic targets that cannot be deduced by standard genetics analyses, which fail to reveal the metabolic information, isoform shifts, protein activation, protein complexes, and protein degradation critical to our discoveries.

Long-term aerobic exercise protects against cisplatin-induced nephrotoxicity by modulating the expression of IL-6 and HO-1

Nephrotoxicity is substantial side effect for 30% of patients undergoing cancer therapy with cisplatin and may force them to change or even abandon the treatment. Studies regarding aerobic exercise have shown its efficacy for the treatment of many types of diseases and its capacity to reduce tumors. However, little is known about the impact of physical exercise on cisplatin-induced acute kidney injury (AKI). In the present study, our aim was to investigate the role of physical exercise in AKI induced by cisplatin. We submitted C57Bl6 male mice to seven weeks of chronic exercise on a training treadmill and treated them with single i.p. injection of cisplatin (20 mg/kg) in the last week. Exercise efficacy was confirmed by an increased capillary-to-fiber ratio in the gastrocnemius muscle of exercised groups (EX and CIS-EX). The group submitted to exercise before cisplatin administration (CIS-EX) exhibited less weight loss and decreased serum urea levels compared to the cisplatin group (CIS). Exercise also showed a protective role against cisplatin-induced cell death in the kidney. The CIS-EX group showed a lower inflammatory response, with less TNF and IL-10 expression in the kidney and serum. In the same group, we observed an increase of IL-6 and HO-1 expression in the kidney. Taken together, our results indicate that chronic aerobic exercise is able to attenuate AKI by inducing IL-6 and HO-1 production, which results in lower inflammatory and apoptotic profiles in the kidney.

Tumor xenograft uptake of a pyrrole-imidazole (Py-Im) polyamide varies as a function of cell line grafted

Subcutaneous xenografts represent a popular approach to evaluate efficacy of prospective molecular therapeutics in vivo. In the present study, the C-14 labeled radioactive pyrrole–imidazole (Py-Im) polyamide 1, targeted to the 5′-WGWWCW-3′ DNA sequence, was evaluated with regard to its uptake properties in subcutaneous xenografts, derived from the human tumor cell lines LNCaP (prostate), A549 (lung), and U251 (brain), respectively. Significant variation in compound tumor concentrations was seen in xenografts derived from these three cell lines. Influence of cell line grafted on systemic polyamide elimination was established. With A549, a marked variation in localization of 1 was determined between Matrigel-negative and -positive xenografts. An extensive tissue distribution analysis of 1 in wild-type animals was conducted, enabling the comparison between the xenografts and the corresponding host organs of origin.

Neurotoxicity of cancer chemotherapy

There is accumulating clinical evidence that chemotherapeutic agents induce neurological side effects, including memory deficits and mood disorders, in cancer patients who have undergone chemotherapeutic treatments. This review focuses on chemotherapy-induced neurodegeneration and hippocampal dysfunctions and related mechanisms as measured by in vivo and in vitro approaches. These investigations are helpful in determining how best to further explore the causal mechanisms of chemotherapy-induced neurological side effects and in providing direction for the future development of novel optimized chemotherapeutic agents.

Neuropsychological care and rehabilitation of cancer patients with chemobrain: strategies for evaluation and intervention development

Malignant tumors and their various treatments such as chemotherapy, radiotherapy and hormonal therapy can deleteriously affect a large number of cancer patients and survivors on multiple dimensions of psychosocial and neurocognitive functioning. Oncology researchers and clinicians are increasingly cognizant of the negative effects of cancer and its treatments on the brain and its mental processes and cognitive outcomes. Nevertheless, effective interventions to treat cancer and treatment-related neurocognitive dysfunction (CRND), also known as chemobrain, are still lacking. The paucity of data on effective treatments for CRND is due, at least partly, to difficulties understanding its etiology, and a lack of reliable methods for assessing its presence and severity. This paper provides an overview of the incidence, etiology, and magnitude of CRND, and discusses the plausible contributions of psychological, motor function, and linguistic and behavioral complications to CRND. Strategies for reliable neuropsychological screening and assessment, and development and testing of effective ways to mitigate CRND are also discussed.

Nurse self-evaluation of assessment of chemotherapy-induced peripheral neuropathy in patients with cancer

The focus of this study was to assess the feasibility and clinical implementation of a standardized assessment for chemotherapy-induced peripheral neuropathy (CIPN) by registered nurses in patients undergoing neurotoxic chemotherapy. A total of 24 registered nurses from 4 different institutions were enrolled into the study. A pre- and posttest design was used to assess changes in nurses’ attitudes, knowledge, and perceived skill in CIPN assessment. Using selected data collection instruments, nurses performed standardized assessments during the course of chemotherapy treatments. Patient-reported symptoms, vibratory sensation, deep-tendon reflexes, and touch were collected at three time points during chemotherapy treatment. Results indicated there was no statistically significant change in knowledge of chemotherapy-induced peripheral neuropathy from baseline to the end of the study. However, this finding may be due to poor internal consistency noted among the items of the Nurse Knowledge and Attitudes CIPN Assessment. Implementation of a standardized subjective and objective nursing assessment of CIPN was feasible with a total mean feasibility score of 3.76 (range 0–5) with each individual item scoring between 3.35 and 3.91. The intervention did improve pretest and posttest confidence in performing assessment for CIPN (p = .003).

Chemotherapy dose reduction due to chemotherapy induced peripheral neuropathy in breast cancer patients receiving chemotherapy in the neoadjuvant or adjuvant settings: a single-center experience

Purpose

Taxanes are a cornerstone treatment in early and advanced stage breast cancer and in other common solid tumor malignancies; however, the development of chemotherapy induced peripheral neuropathy (CIPN) often necessitates dose-reduction, which may hamper the effectiveness of the drug and compromise survival outcomes especially when used in the adjuvant setting. Limited literature is available on the prevalence and severity of dose reduction due to CIPN. We sought to determine the frequency and severity of CIPN-induced dose reduction in early stage breast cancer patients who received taxane-based chemotherapy in the neoadjuvant or adjuvant settings.

Methods

We conducted a retrospective single-institution breast cancer clinic chart review of 123 newly diagnosed breast cancer patients and treated with taxane-based neoadjuvant/adjuvant chemotherapy at the University of Maryland Greenebaum Cancer Center between January 2008 and December 2011.

Results

Forty-nine of 123 (40%; 95% CI: 31-49%) patients required dose reduction. Twenty-one (17%; 95% CI: 11-25%) of these patients were dose-reduced specifically due to CIPN that developed during treatment. The median relative dose intensity (received dose/planned dose) for the 21 CIPN-induced dose reduction patients was 73.4% (range, 68.0-94.0%). Patients with diabetes appeared to have a higher risk of taxane-induced dose reduction (p-value=0.01). African-American patients and those treated with paclitaxel (rather than docetaxel) experienced a higher-risk of CIPN-induced dose reduction (p-values are <0.001 and 0.001, respectively).

Conclusions

The incidence of CIPN-associated dose reduction in our patient population was 17%. African-American patients, diabetics and subjects treated with paclitaxel had a higher risk for CIPN-associated dose reduction in our study.

Neuropathic pain in cancer survivors

The occurrence of pain in cancer survivors may be debilitating. These pain syndromes may be of different types, including neuropathic pain. The research related to cancer management has been done extensively in certain areas, but such research in cancer survivors is still lacking. The chronic pain in cancer survivors is not only under-reported but also under-treated. The assessment of pain in cancer survivors is multifaceted because of many domains like physical, social and psychological. Usually, the pain management may be considered similar to that for chronic noncancer pain, but with a caveat that such pain may at times be indicative of cancer recurrence. The multidisciplinary and multimodal management is essential for such neuralgic pain in cancer survivors. This may require a balanced combination of pharmacological and nonpharmacological techniques, including psychological support. The overall goal that remains in such patients for pain management is to improve the quality of life. Here we review certain pertinent aspects of neuropathic pain in cancer survivors.

Altered cerebral blood flow one month after systemic chemotherapy for breast cancer: a prospective study using pulsed arterial spin labeling MRI perfusion

Cerebral structural and functional alterations have been reported after chemotherapy for non-CNS cancers, yet the causative mechanism behind these changes remains unclear. This study employed a novel, non-invasive, MRI-based neuroimaging measure to provide the first direct longitudinal measurement of resting cerebral perfusion in breast cancer patients, which was tested for association with changes in cognitive function and gray matter density. Perfusion was measured using pulsed arterial spin labeling MRI in women with breast cancer treated with (N = 27) or without (N = 26) chemotherapy and matched healthy controls (N = 26) after surgery before other treatments (baseline), and one month after chemotherapy completion or yoked intervals. Voxel-based analysis was employed to assess perfusion in gray matter; changes were examined in relation to overall neuropsychological test performance and frontal gray matter density changes measured by structural MRI. Baseline perfusion was not significantly different across groups. Unlike control groups, chemotherapy-treated patients demonstrated significantly increased perfusion post-treatment relative to baseline, which was statistically significant relative to controls in the right precentral gyrus. This perfusion increase was negatively correlated with baseline overall neuropsychological performance, but was not associated with frontal gray matter density reduction. However, decreased frontal gray matter density was associated with decreased perfusion in bilateral frontal and parietal lobes in the chemotherapy-treated group. These findings indicate that chemotherapy is associated with alterations in cerebral perfusion which are both related to and independent of gray matter changes. This pattern of results suggests the involvement of multiple mechanisms of chemotherapy-induced cognitive dysfunction. Additionally, lower baseline cognitive function may be a risk factor for treatment-associated perfusion dysregulation. Future research is needed to clarify these mechanisms, identify individual differences in susceptibility to treatment-associated changes, and further examine perfusion change over time in survivors.

Ptosis during hematologic malignancy in children

Neurological symptoms such as ptosis may develop due to either chemotherapeutic agents or involvement of the central nervous system (CNS) during hematologic malignancy. It is difficult to make this distinction according to clinical symptoms and magnetic resonance imaging findings. If the neurologic symptoms are increased, it is a warning of CNS involvement. Herein are described the clinical and neuroimaging features of three patients with hematologic malignancy who presented with ptosis.

North Central Cancer Treatment Group/Alliance trial N08CA-the use of glutathione for prevention of paclitaxel/carboplatin-induced peripheral neuropathy: a phase 3 randomized, double-blind, placebo-controlled study

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a significant side effect of taxane and platinum-based chemotherapy. Several studies have supported the potential benefit of glutathione for the prevention of platinum-induced CIPN. The current trial was designed to determine whether glutathione would prevent CIPN as a result of carboplatin/paclitaxel therapy.

METHODS

In total, 185 patients who received treatment with paclitaxel and carboplatin were accrued between December 4, 2009 and December 19, 2011. Patients were randomized to receive either placebo (n = 91) or 1.5 g/m(2) glutathione (n = 94) over 15 minutes immediately before chemotherapy. CIPN was assessed using the European Organization for Research and Treatment of Cancer Quality-of-Life (EORTC-QLQ) 20-item, CIPN-specific (CIPN20) sensory subscale and the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 4.0.

RESULTS

There were no statistically significant differences between the 2 study arms with regard to: 1) peripheral neurotoxicity, as assessed using both the EORTC-QLQ-CIPN20 (P = .21) and the CTCAE scales (P = .449 for grade ≥2 neurotoxicity; P = .039 for time to development of grade ≥2 neuropathy, in favor of the placebo); 2) the degree of paclitaxel acute pain syndrome (P = .30 for patients who received paclitaxel every 3-4 weeks and P = .002, in favor of the placebo, for patients who received weekly paclitaxel); 3) the time to disease progression (P = .63); or 4) apparent toxicities. Subgroup analyses did not reveal any evidence of benefit in any particular subgroup.

CONCLUSIONS

The results from this study do not support the use of glutathione for the prevention of paclitaxel/carboplatin-induced CIPN.

Oral alpha-lipoic acid to prevent chemotherapy-induced peripheral neuropathy: a randomized, double-blind, placebo-controlled trial

OBJECTIVES

Chemotherapy-induced peripheral neuropathy is frequently a dose-limiting factor in cancer treatment and may cause pain and irreversible function loss in cancer survivors. We tested whether alpha-lipoic acid (ALA) could decrease the severity of peripheral neuropathy symptoms in patients undergoing platinum-based chemotherapy.

METHODS

Cancer patients 18 years or older were randomly selected to receive either 600 mg ALA or a placebo three times a day orally for 24 weeks while receiving chemotherapy regimens including cisplatin or oxaliplatin. Neuropathy was measured by the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) scale and the NCI Common Toxicity Criteria for Adverse Events neurotoxicity grades. Results from timed functional tests and the Brief Pain Inventory (BPI) were secondary endpoints.

RESULTS

Seventy of 243 (29 %) patients completed the study (24 weeks). Both the ALA and the placebo arms had a comparable drop-out rate. No statistically significant differences were found between the ALA and the placebo groups for FACT/GOG-Ntx scores, BPI scores, and patients' functional outcomes.

CONCLUSION

This strategy of oral ALA administration was ineffective at preventing neurotoxicity caused by oxaliplatin or cisplatin. High attrition rates due to poor patient compliance and manner of dosage administration in this trial demonstrated a lack of feasibility for this intervention. Future studies to explore ALA as a neuroprotective agent should take heed of the barriers confronted in this study.

Characteristics and Quality of Life in Gynecologic Cancer Patients with Chemotherapy-induced Peripheral Neuropathy

PURPOSE

The purpose of this study was to identify chemotherapy induced peripheral neuropathy, quality of life of patients with gynecologic cancer.

METHODS

This was a cross-sectional survey design. We collected 130 patients with gynecologic cancer. They complete a self reported questionnaire including items related neuropathy and quality of life (FACT-GOG/Ntx subscale, FACT-G scale).

RESULTS

The neuropathy score was 14.3+/-7.9. The quality of life score was 64.8+/-16.4. The neuropathy induced significant difference according to diabetic status, difficulties in performing household chores and willing to discontinuity of chemotherapy. And duration of cancer diagnosis, neuropathy, number of total chemo agent associated with quality of life. There was a negative correlation between number of total chemo agent and quality of life. Neuropathy independently affected quality of life.

CONCLUSION

Chemotherapy induced peripheral neuropathy of patients with gynecologic cancer adversely affected women's quality of life and activities of daily living. To improve patient's quality of life, it is important that accurate assess and appropriately manage neuropathy in patients with gynecologic cancer.

Cisplatin inhibits hippocampal cell proliferation and alters the expression of apoptotic genes

The hippocampus, which is critical for memory and spatial navigation, contains a proliferating stem cell niche that is especially vulnerable to antineoplastic drugs such as cisplatin. Although the damaging effects of cisplatin have recently been recognized, the molecular mechanisms underlying its toxic effects on this vital region are largely unknown. Using a focused apoptosis gene array, we analyzed the early cisplatin-induced changes in gene expression in the hippocampus of adult Sprague-Dawley rats and compared the results to those from the inferior colliculus, a non-mitotic auditory region resistant to cisplatin-induced cell death. Two days after a 12 mg/kg dose of cisplatin, significant increases were observed in five proapoptotic genes: Bik, Bid, Bok, Trp53p2, and Card6 and a significant decrease in one antiapoptotic gene Bcl2a1. In contrast, Nol3, an antiapoptotic gene, showed a significant increase in expression. The cisplatin-induced increase in Bid mRNA and decrease in Bcl2a1 mRNA were accompanied by a corresponding increase and decrease of their respective proteins in the hippocampus. In contrast, the cisplatin-induced changes in Bcl2a1, Bid, Bik, and Bok gene expression in the inferior colliculus were strikingly different from those in the hippocampus consistent with the greater susceptibility of the hippocampus to cisplatin toxicity. Cisplatin also significantly reduced immunolabeling of the cell proliferation marker Ki67 in the subgranular zone of the hippocampus 2 days post-treatment. These results indicate that cisplatin-induced hippocampal cell death is mediated by increased expression of proapoptotic and decreased antiapoptotic genes and proteins that likely inhibit hippocampal cell proliferation.