Cancer survivors treated with platinum-based chemotherapy affected by ototoxicity and the impact on quality of life: a narrative synthesis systematic review

Circulating IL-17 reduces the risk of cisplatin-induced hearing loss in children: a bidirectional two-sample Mendelian randomization study

Studies have reported that cytokines and their related signaling pathways play a role in inner ear diseases. In clinical practice, approximately 50% of pediatric cancer patients experience irreversible hearing loss after cisplatin treatment. However, currently, there is a lack of systematic research on the causal relationship between circulating cytokines and cisplatin-induced hearing loss in children. Genetic variant data for 41 circulating cytokines were obtained from a meta-analysis of genome-wide association studies (GWAS) among 8293 individuals of Finnish descent. The GWAS data for Cisplatin-induced hearing loss in children were derived from a multicenter cohort of European pediatric cancer patients and survivors (N = 390), including both cases with hearing loss after cisplatin chemotherapy and controls without hearing loss. Multiple methods were employed for bidirectional Mendelian randomization (MR) estimation. Bonferroni correction was applied to adjust the original P-values, followed by a series of sensitivity analyses. In the directional Mendelian randomization (MR) analysis, it was found that IL-17 was significantly associated with a reduced risk of Cisplatin-induced hearing loss in children (OR: 0.18, CI: 0.06-0.48, P < 0.001, FDR = 0.041). In the reverse MR analysis, there were some nominal causal relationships of Cisplatin-induced hearing loss in children with certain cytokines [M-CSF: (OR: 1.04, CI: 1.01-1.08, P = 0.010, FDR = 0.41); IL-2RA: (OR: 1.03, CI: 1.00-1.05, P = 0.044, FDR = 0.447); MIP-1β: (OR: 1.02, CI: 1.00-1.04, P = 0.041, FDR = 0.447)]. leave-one-out analysis demonstrated that only M-CSF exhibited stability. These findings reveal a causal relationship between IL-17 and cisplatin-induced hearing loss in children. Further research is needed to determine the potential protective mechanisms of IL-17 in cisplatin-induced ototoxicity.

Communication, academic and social outcomes of childhood cancer survivors with hearing loss: A systematic review

Many children treated for cancer are at risk of hearing loss. However, little is known about how hearing loss impacts their communication, academic and social outcomes. To examine the impact, this systematic review aimed to synthesise and appraise quantitative and qualitative studies reporting on (i) participants with hearing loss treated with platinum-based chemotherapy or cranial radiotherapy during childhood; and (ii) speech, language, academic performance, or social participation findings. Systematic database searches yielded 23 relevant articles that were analysed using narrative synthesis. Difficulties were reported for some but not all communication, academic and social aspects; however, a quality assessment using Grading of Recommendations Assessment, Development and Evaluation (GRADE) revealed low to very low certainty in the findings. Future research should aim to increase the quality of the research evidence and explore how multidisciplinary services can provide evidence-based support for childhood cancer survivors with competing hearing, communication, and social difficulties.

Cisplatin-Induced Ototoxicity: A Concise Review of the Burden, Prevention, and Interception Strategies

Cisplatin is a bedrock of cancer management and one of the most used chemotherapeutic agents in the treatment of germ cell, lung, bladder, ovarian, and head and neck cancers. Approximately 500,000 patients diagnosed annually with these cancer types in the United States could be candidates for treatment with cisplatin. There is a 5-fold increase in the risk of hearing impairment or ototoxicity with cisplatin, which can manifest as ringing in the ear (tinnitus), high-frequency hearing loss, and at late stages, a decreased ability to hear normal conversation. More than half of adult and pediatric patients with cancer treated with cisplatin developed hearing impairment with major impact on patients' health-related quality of life. A considerable evidence gap persists regarding the burden and effective prevention and interception strategies for cisplatin-induced ototoxicity, especially in adult patients with cancer. We conducted a review of the published literature to provide an update on the status of this important clinical challenge. We also surveyed practicing oncologists within our network of academic and community practices to gain a better understanding of how the published literature compares with real-world practice. Our review of the literature showed a lack of standardized guidelines for monitoring and treatment of cisplatin-induced ototoxicity, especially in the adult cancer patient population. Our survey of practicing oncologists mirrored the findings from the published literature with a heterogeneity of practice, which highlights the need for standardization.

Ototoxicity Review: A Growing Number of Non-Platinum-Based Chemo- and Immunotherapies

OBJECTIVE

To raise awareness of the growing list of non-platinum-based chemo- and immunotherapeutic agents that have been associated with ototoxicity and to introduce the possible mechanism of ototoxicity of these agents.

DATA SOURCES

PubMed, Embase, and Web of Science.

REVIEW METHODS

A systematic review was performed following the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses). PubMed, Embase, and Web of Science databases were searched for published reports of ototoxicity from non-platinum-based chemo- and immunotherapeutic agents in adult and pediatric patients. Therapies that utilized any platinum-based agent were excluded.

CONCLUSIONS

Ototoxicity from non-platinum-based chemo- and immunotherapies is an evolving problem. There were 54 reports-39 case reports and 15 cohort studies-documenting ototoxicity from 7 agents/combination therapies. Of these reports, 37 (69%) were published within the last 15 years (after 2005). No recovery of hearing was documented in 21 of 56 cases (38%). Pretreatment audiograms were uncommon (19/54 studies, 35%), despite documented ototoxic associations.

IMPLICATIONS FOR PRACTICE

There is a growing number of novel, ototoxic, non-platinum-based chemo- and immunotherapeutic agents with various potential mechanisms of action. Otolaryngologists will need to prioritize awareness of these agents. This growing list of agents, many of which have reversible effects, suggest a need for standardized ototoxicity monitor protocols so that appropriate and timely management options can be implemented.

Association of Clinical Aspects and Genetic Variants with the Severity of Cisplatin-Induced Ototoxicity in Head and Neck Squamous Cell Carcinoma: A Prospective Cohort Study

Background: Cisplatin (CDDP) is a major ototoxic chemotherapy agent for head and neck squamous cell carcinoma (HNSCC) treatment. Clinicopathological features and genotypes encode different stages of CDDP metabolism, as their coexistence may influence the prevalence and severity of hearing loss. Methods: HNSCC patients under CDDP chemoradiation were prospectively provided with baseline and post-treatment audiometry. Clinicopathological features and genetic variants encoding glutathione S-transferases (GSTT1, GSTM1, GSTP1), nucleotide excision repair (XPC, XPD, XPF, ERCC1), mismatch repair (MLH1, MSH2, MSH3, EXO1), and apoptosis (P53, CASP8, CASP9, CASP3, FAS, FASL)-related proteins were analyzed regarding ototoxicity. Results: Eighty-nine patients were included, with a cumulative CDDP dose of 260 mg/m2. Moderate/severe ototoxicity occurred in 26 (29%) patients, particularly related to hearing loss at frequencies over 3000 Hertz. Race, body-mass index, and cumulative CDDP were independent risk factors. Patients with specific isolated and combined genotypes of GSTM1, GSTP1 c.313A>G, XPC c.2815A>C, XPD c.934G>A, EXO1 c.1762G>A, MSH3 c.3133A>G, FASL c.-844A>T, and P53 c.215G>C SNVs had up to 32.22 higher odds of presenting moderate/severe ototoxicity. Conclusions: Our data present, for the first time, the association of combined inherited nucleotide variants involved in CDDP efflux, DNA repair, and apoptosis with ototoxicity, which could be potential predictors in future clinical and genomic models.

Prevalence and risk factors for ototoxicity after cisplatin-based chemotherapy

PURPOSE

Ototoxicity is a prominent side effect of cisplatin-based chemotherapy. There are few reports, however, estimating its prevalence in well-defined cohorts and associated risk factors.

METHODS

Testicular cancer (TC) survivors given first-line cisplatin-based chemotherapy completed validated questionnaires. Descriptive statistics evaluated the prevalence of ototoxicity, defined as self-reported hearing loss and/or tinnitus. We compared patients with and without tinnitus or hearing loss using Chi-square test, two-sided Fisher's exact test, or two-sided Wilcoxon rank sum test. To evaluate ototoxicity risk factors, a backward selection logistic regression procedure was performed.

RESULTS

Of 145 TC survivors, 74% reported ototoxicity: 68% tinnitus; 59% hearing loss; and 52% reported both. TC survivors with tinnitus were more likely to indicate hypercholesterolemia (P = 0.008), and difficulty hearing (P < .001). Tinnitus was also significantly related to age at survey completion (OR = 1.79; P = 0.003) and cumulative cisplatin dose (OR = 5.17; P < 0.001). TC survivors with hearing loss were more likely to report diabetes (P = 0.042), hypertension (P = 0.007), hypercholesterolemia (P < 0.001), and family history of hearing loss (P = 0.044). Risk factors for hearing loss included age at survey completion (OR = 1.57; P = 0.036), hypercholesterolemia (OR = 3.45; P = 0.007), cumulative cisplatin dose (OR = 1.94; P = 0.049), and family history of hearing loss (OR = 2.87; P = 0.071).

CONCLUSIONS

Ototoxicity risk factors included age, cisplatin dose, cardiovascular risk factors, and family history of hearing loss. Three of four TC survivors report some type of ototoxicity; thus, follow-up of cisplatin-treated survivors should include routine assessment for ototoxicity with provision of indicated treatments.

IMPLICATIONS FOR CANCER SURVIVORS

Survivors should be aware of risk factors associated with ototoxicity. Referrals to audiologists before, during, and after cisplatin treatment is recommended.

The long-term impacts of hearing loss, tinnitus and poor balance on the quality of life of people living with and beyond cancer after platinum-based chemotherapy: a literature review

PURPOSE

To elucidate the long-term impacts of hearing loss, tinnitus and balance in people living with and beyond cancer (LWBC) treated with platinum-based chemotherapy (PBCT).

METHODS

A literature search was conducted between March and June 2022 using PubMed, Web of Science and Google Scholar. Full-text papers in English were included. Articles explored the impacts of hearing loss, tinnitus and balance and discussed them in the context of treatment. If PBCT was used in conjunction with other treatments, the article was included. There were no constraints on age, cancer type, publication date, location, study design or data type. Sixteen studies and two reviews were included.

RESULTS

Hearing loss and tinnitus can cause communication difficulties and subsequent social withdrawal. There were deficits in cognition, child development and educational performance. Employment and the ease of everyday life were disrupted by hearing loss and tinnitus, whereas poor balance interfered with walking and increased the risk of falls. Depression and anxiety were related to ototoxicity. Most notable were the differing mindsets experienced by adults LWBC with ototoxicity. There was evidence of inadequate monitoring of ototoxicity by clinicians and a lack of communication between clinicians and patients about ototoxicity as a side effect.

CONCLUSIONS

Ototoxicity has a negative long-term impact on multiple areas of life for adults and children LWBC. This can compromise their quality of life.

IMPLICATIONS FOR CANCER SURVIVORS

Increased awareness, monitoring and education surrounding these issues may lead to earlier intervention and better management of ototoxicity, enhancing the quality of life of people LWBC.

Audiologists' perceived value of ototoxicity management and barriers to implementation for at-risk cancer patients in VA: the OtoMIC survey

PURPOSE

Platinum-based chemotherapies used to treat many types of cancers are ototoxic. Ototoxicity management (OtoM) to mitigate the ototoxic outcomes of cancer survivors is recommended practice yet it is not a standard part of oncologic care. Although more than 10,000 patients each year are treated with platinum-based chemotherapies at the US Veterans Health Administration (VA), the current state of OtoM in VA is not well-defined. This study reports on a national survey of VA audiologists' perceptions regarding OtoM in cancer patients.

METHODS

A 26-item online survey was administered to VA audiologists and service chiefs across the VA's 18 regional systems of care. Descriptive statistics and deductive thematic analysis were used to analyze the data.

RESULTS

The 61 respondents included at least one from each VA region. All reported they felt some form of OtoM was necessary for at-risk cancer patients. A pre-treatment baseline, the ability to detect ototoxicity early, and management of ototoxic effects both during and after treatment were considered high value objectives of OtoM by respondents. Roughly half reported routinely providing these services for patients receiving cisplatin and carboplatin. Respondents disagreed regarding appropriate hearing testing schedules and how to co-manage OtoM responsibilities with oncology. They identified barriers to care that conformed to three themes: care and referral coordination with oncology, audiology workload, and lack of protocols.

CONCLUSIONS

Although VA audiologists value providing OtoM for cancer patients, only about half perform OtoM for highly ototoxic treatment regimens. The OtoMIC survey provides clinician perspectives to benchmark and address OtoM care gaps.

IMPLICATIONS FOR CANCER SURVIVORS

Collaboration between oncology and audiology is needed to improve current OtoM processes, so that cancer survivors can have more control over their long term hearing health.

Ototoxicity prognostic models in adult and pediatric cancer patients: a rapid review

PURPOSE

A cornerstone of treatment for many cancers is the administration of platinum-based chemotherapies and/or ionizing radiation, which can be ototoxic. An accurate ototoxicity risk assessment would be useful for counseling, treatment planning, and survivorship follow-up in patients with cancer.

METHODS

This systematic review evaluated the literature on predictive models for estimating a patient's risk for chemotherapy-related auditory injury to accelerate development of computational approaches for the clinical management of ototoxicity in cancer patients. Of the 1195 articles identified in a PubMed search from 2010 forward, 15 studies met inclusion for the review.

CONCLUSIONS

All but 1 study used an abstraction of the audiogram as a modeled outcome; however, specific outcome measures varied. Consistently used predictors were age, baseline hearing, cumulative cisplatin dose, and radiation dose to the cochlea. Just 5 studies were judged to have an overall low risk of bias. Future studies should attempt to minimize bias by following statistical best practices including not selecting multivariate predictors based on univariate analysis, validation in independent cohorts, and clearly reporting the management of missing and censored data. Future modeling efforts should adopt a transdisciplinary approach to define a unified set of clinical, treatment, and/or genetic risk factors. Creating a flexible model that uses a common set of predictors to forecast the full post-treatment audiogram may accelerate work in this area. Such a model could be adapted for use in counseling, treatment planning, and follow-up by audiologists and oncologists and could be incorporated into ototoxicity genetic association studies as well as clinical trials investigating otoprotective agents.

IMPLICATIONS FOR CANCER SURVIVORS

Improvements in the ability to model post-treatment hearing loss can help to improve patient quality of life following cancer care. The improvements advocated for in this review should allow for the acceleration of advancements in modeling the auditory impact of these treatments to support treatment planning and patient counseling during and after care.

Surveillance for ototoxicity in platinum-based chemotherapy using mobile health audiometry with extended high frequencies

OBJECTIVE

This study investigated mobile health enabled surveillance in ototoxicity.

METHOD

This was a longitudinal study of 32 participants receiving chemotherapy. Baseline and exit audiograms that included conventional and extended high frequency audiometry were recorded within the patient's treatment venue using a validated mobile health audiometer.

RESULTS

Average hearing thresholds at baseline were within the normal range (81.2 per cent left; 93.8 per cent right), reducing at exit testing (71.9 per cent left; 78.1 per cent right). Half of participants presented with a threshold shift according to ototoxicity monitoring criteria. The frequencies affected the most were between 4000 and 16 000 Hz, with left ears significantly more affected than right ears. Noise levels exceeded the maximum permissible ambient noise levels in up to 43.8 per cent of low frequencies (250-1000 Hz).

CONCLUSION

Mobile health supported audiometry proved to be an efficacious tool for ototoxicity monitoring at the treatment venue. Changes in hearing ability over time could be tracked, improving surveillance in patients with full treatment schedules.

Liquid Crystalline Nanoparticles Conjugated with Dexamethasone Prevent Cisplatin Ototoxicity In Vitro

The conjugation of drugs with nanoparticles represents an innovative approach for controlled and targeted administration of therapeutic agents. Nanoparticle-based systems have been tested for the inner ear therapy, increasing the drug diffusion and being detected in all parts of the cochlea when locally applied near the round window. In this study, glycerol monooleate liquid crystalline NanoParticles were conjugated with Dexamethasone (NPD), a hydrophobic drug already used for inner ear treatments but defective in solubility and bioavailability. NPD has been tested in vitro in the cell line OC-k3, a model of sensory cells of the inner ear, and the therapeutic efficacy has been evaluated against cisplatin, a chemotherapeutic compound known to induce ototoxicity. After comparing the physical chemical characteristics of NPD to the equivalent naïve nanoparticles, an initial investigation was carried out into the nanoparticle's uptake in OC-k3 cells, which takes place within a few hours of treatment without causing toxic damage up to a concentration of 50 µg/mL. The NPD delivered the dexamethasone inside the cells at a significantly increased rate compared to the equivalent free drug administration, increasing the half-life of the therapeutic compound within the cell. Concerning the co-treatment with cisplatin, the NPD significantly lowered the cisplatin cytotoxicity after 48 h of administration, preventing cell apoptosis. To confirm this result, also cell morphology, cell cycle and glucocorticoids receptor expression were investigated. In conclusion, the NPD system has thus preliminarily shown the potential to improve the therapeutic efficacy of treatments delivered in the inner ear and prevent drug-induced ototoxicity.

Ototoxicity monitoring in South African cancer facilities: A national survey

Background

National information regarding ototoxicity monitoring practices are limited for patients undergoing chemotherapy in South Africa.

Objectives

To determine (1) the national status of ototoxicity monitoring implemented in private and public cancer facilities, (2) the knowledge and ototoxicity monitoring approaches implemented, and (3) reported challenges.

Method

A descriptive quantitative survey was conducted in public and private oncology units and audiology referral clinics. Private (60%) and public (43%) oncology units that provide platinum-based chemotherapy in South Africa and audiology referral units (54%) were: (1) surveyed telephonically to determine if ototoxicity monitoring takes place; and (2) a self-administered survey was sent to qualifying oncology units and audiology referral clinics.

Results

All public oncology units reported that ototoxicity monitoring only occurs on referral and is not standard practice. All private oncology units indicated that monitoring is on a patient self-referral basis when symptoms occur. Poor awareness of ototoxicity monitoring best practice guidelines was reported by all oncology units and 14% of audiology referral clinics. Audiology referral clinics reported adequate knowledge of ototoxicity protocols although they are not widely used with only 43% following best practice guidelines. The most prominent challenges reported by participants was referral system (67% oncology units; 57% audiology referral clinics), environmental noise (83% oncology units; 86% audiology referral clinics) and the compromised status of cancer patients (67% oncology units; 57% audiology referral clinics).

Conclusion

Ototoxicity monitoring is not routinely implemented across oncology units in South Africa. Multidisciplinary teamwork and a simplified national ototoxicity monitoring protocol may improve hearing outcomes for patients.

The impact of chemotherapy-induced inner ear damage on quality of life in cancer survivors: a qualitative study

PURPOSE

This study aimed to explore the burden of inner ear damage (ototoxicity) on adults living with and beyond cancer treated with chemotherapy and  the impact on their quality of life (QoL). Furthermore, this study aimed to explore patient awareness surrounding chemotherapy-induced inner ear damage, known as ototoxicity, and assess what support they had been offered.

METHODS

Participants were adults who had undergone chemotherapy, recruited from cancer clinics, charities and social media. Using semi-structured interviews and fieldnotes, an inductive thematic analysis was used to develop key themes surrounding this topic.

RESULTS

Twenty participants from the UK were interviewed. Two key themes were developed from the thematic analysis, cancer-related QoL and ototoxicity-related QoL, with each one including 5 subthemes. Subthemes consisted of impact of ototoxicity, hearing, tinnitus, clinical experience, audiological assessments, and impact of treatment, cancer and chemotherapy, other toxicities, information and patient reflections.

CONCLUSIONS

Ototoxicity can have a negative impact on QoL, specifically on social life and the fear of hearing loss and/or tinnitus worsening. There are opportunities for increased awareness by patients and clinicians, including improved information sources, and hearing monitoring not only for those undergoing platinum-based chemotherapy but many others surviving after treatment for cancer.

IMPLICATIONS FOR CANCER SURVIVORS

Better monitoring of hearing and information about ototoxicity during chemotherapy could potentially reduce the fear of the symptoms of ototoxicity worsening. Furthermore, hearing monitoring would facilitate the detection of hearing loss at early stages of survivorship, which would facilitate earlier access to clinical interventions and longer term counselling.

Review of Pharmacotherapy for Tinnitus

Various medications are currently used in the treatment of tinnitus, including anesthetics, antiarrhythmics, anticonvulsants, antidepressants, antihistamines, antipsychotics, anxiolytics, calcium channel blockers, cholinergic antagonists, NMDA antagonists, muscle relaxants, vasodilators, and vitamins. To date, however, no medications have been specifically approved to treat tinnitus by the US Food and Drug Administration (FDA). In addition, medicines used to treat other diseases, as well as foods and other ingested materials, can result in unwanted tinnitus. These include alcohol, antineoplastic chemotherapeutic agents and heavy metals, antimetabolites, antitumor agents, antibiotics, caffeine, cocaine, marijuana, nonnarcotic analgesics and antipyretics, ototoxic antibiotics and diuretics, oral contraceptives, quinine and chloroquine, and salicylates. This review, therefore, describes the medications currently used to treat tinnitus, including their mechanisms of action, therapeutic effects, dosages, and side-effects. In addition, this review describes the medications, foods, and other ingested agents that can induce unwanted tinnitus, as well as their mechanisms of action.

Natural history of tinnitus in adults: a cross-sectional and longitudinal analysis

OBJECTIVE

To assess incidence and changes in tinnitus and bothersome tinnitus as well as associated risk factors in a large sample of UK adults.

DESIGN

Prospective cohort study.

SETTING

UK.

PARTICIPANTS

For cross-sectional analysis, a group of 168 348 participants aged between 40 and 69 years with hearing and tinnitus data from the UK Biobank resource. Longitudinal analysis included a subset of 4746 people who attended a 4-year retest assessment.

MAIN OUTCOME MEASURES

Presence and bothersomeness of tinnitus.

RESULTS

17.7% and 5.8% of participants reported tinnitus or bothersome tinnitus, respectively. The 4-year incidence of tinnitus was 8.7%. Multivariate logistic regression models suggested that age, hearing difficulties, work noise exposure, ototoxic medication and neuroticism were all positively associated with both tinnitus and bothersome tinnitus. Reduced odds of tinnitus, but not bothersome tinnitus, was seen in alcohol drinkers versus non-drinkers. Male gender was associated with increased odds of tinnitus, while female gender was associated with increased odds of bothersome tinnitus. At follow-up, of those originally reporting tinnitus, 18.3% reported no tinnitus. Of those still reporting tinnitus, 9% reported improvement and 9% reported tinnitus becoming more bothersome, with the rest unchanged. Male gender and alcohol consumption were associated with tinnitus being reported less bothersome, and hearing difficulties were associated with the odds of tinnitus being reported as more bothersome.

CONCLUSIONS

This study is one of the few to provide data on the natural history of tinnitus in a non-clinical population, suggesting that resolution is relatively uncommon, with improvement and worsening of symptoms equally likely. There was limited evidence for any modifiable lifestyle factors being associated with changes in tinnitus symptoms. In view of the largely persistent nature of tinnitus, public health strategies should focus on: (1) primary prevention and (2) managing symptoms in people that have tinnitus and monitoring changes in bothersomeness.

Potential use of n-3 PUFAs to prevent oxidative stress-derived ototoxicity caused by platinum-based chemotherapy

Platinum-based compounds are widely used for the treatment of different malignancies due to their high effectiveness. Unfortunately, platinum-based treatment may lead to ototoxicity, an often-irreversible side effect without a known effective treatment and prevention plan. Platinum-based compound-related ototoxicity results mainly from the production of toxic levels of reactive oxygen species (ROS) rather than DNA-adduct formation, which has led to test strategies based on direct ROS scavengers to ameliorate hearing loss. However, favorable clinical results have been associated with several complications, including potential interactions with chemotherapy efficacy. To understand the contribution of the different cytotoxic mechanisms of platinum analogues on malignant cells and auditory cells, the particular susceptibility and response of both kinds of cells to molecules that potentially interfere with these mechanisms, is fundamental to develop innovative strategies to prevent ototoxicity without affecting antineoplastic effects. The n-3 long-chain polyunsaturated fatty acids (n-3 PUFAs) have been tried in different clinical settings, including with cancer patients. Nevertheless, their use to decrease cisplatin-induced ototoxicity has not been explored to date. In this hypothesis paper, we address the mechanisms of platinum compounds-derived ototoxicity, focusing on the differences between the effects of these compounds in neoplastic versus auditory cells. We discuss the basis for a strategic use of n-3 PUFAs to potentially protect auditory cells from platinum-derived injury without affecting neoplastic cells and chemotherapy efficacy.

Circadian vulnerability of cisplatin-induced ototoxicity in the cochlea

The chemotherapeutic agent cisplatin is renowned for its ototoxic effects. While hair cells in the cochlea are established targets of cisplatin, less is known regarding the afferent synapse, which is an essential component in the faithful temporal transmission of sound. The glutamate aspartate transporter (GLAST) shields the auditory synapse from excessive glutamate release, and its loss of function increases the vulnerability to noise, salicylate, and aminoglycosides. Until now, the involvement of GLAST in cisplatin-mediated ototoxicity remains unknown. Here, we test in mice lacking GLAST the effects of a low-dose cisplatin known not to cause any detectable change in hearing thresholds. When administered at nighttime, a mild hearing loss in GLAST KO mice was found but not at daytime, revealing a potential circadian regulation of the vulnerability to cisplatin-mediated ototoxicity. We show that the auditory synapse of GLAST KO mice is more vulnerable to cisplatin administration during the active phase (nighttime) when compared to WT mice and treatment during the inactive phase (daytime). This effect was not related to the abundance of platinum compounds in the cochlea, rather cisplatin had a dose-dependent impact on cochlear clock rhythms only after treatment at nighttime suggesting that cisplatin can modulate the molecular clock. Our findings suggest that the current protocols of cisplatin administration in humans during daytime may cause a yet undetectable damage to the auditory synapse, more so in already damaged ears, and severely impact auditory sensitivity in cancer survivors.

Don't forget ototoxicity during the SARS-CoV-2 (Covid-19) pandemic!

Aim of this communication is to remind clinical professionals to be aware of ototoxic side effects of several specific drugs proposed for the treatment of the new virus SARS-CoV-2 (Covid-19). In particular, chloroquine and hydroxychloroquine, azithromycin, as well as antiviral drugs such as remdesivir, favipiravir and lopinavir can all present potential ototoxic side effects. The data in the literature do not offer specific information on their potential synergetic effects nor on their interactions.

Lovastatin protects against cisplatin-induced hearing loss in mice

Cisplatin is used to treat a variety of solid tumors in both children and adults. However, cisplatin has serious side-effects, some of which may permanently affect patients' quality of life following treatment, such as ototoxicity. There is currently no FDA-approved therapy for the prevention or treatment of cisplatin-induced hearing loss. Herein we examine the potential for statins to prevent cisplatin-induced ototoxicity. Statins, a class of drugs commonly used to prevent or manage hypercholesterolemia, have been of clinical utility for decades with dependable outcomes and reliable safety profiles in humans. Statins are known to be protective in animal models of noise-induced and age-related hearing loss. Moreover, studies have demonstrated an additive benefit of statins in cancer treatment. In the current study, lovastatin reduces cisplatin-induced hearing loss in adult mice. Lovastatin-mediated protection was significantly greater among female than male mice, and the dose of lovastatin required for protection was different between the sexes. Taken together our data indicate that lovastatin reduces cisplatin-induced hearing loss in mice and suggest that concurrent statin and cisplatin therapy may represent a feasible clinical strategy for reducing cisplatin-induced ototoxicity that should be explored for future clinical use.

Drug repurposing for anticancer therapies. A lesson from proton pump inhibitors

Introduction: Worldwide, the annual expenditure on anticancer drugs is grossly calculated to be in the order of US$100 billion, and is expected to escalate up to $150 billion by 2020. It is evident that the vast majority of the most recently devised anticancer drugs are unaffordable in economically developing nations, frequently resulting in subpar therapies. In this complex medical and economic scenario, the repurposing of older drugs for anticancer therapies becomes a necessity. The repurposing of antiacid drugs such as the proton pump inhibitors as antitumoral agents and chemosensitizers is probably one of the most recent and promising phenomenon in oncology.Areas covered: Important research articles and patents focusing on proton pump inhibitors as a potential class of therapeutics, published between the period of 2006-2019, have been covered. This review mainly focuses on the therapeutic applications, as direct anticancer agents as well as modifiers of the tumor microenvironment and modulator of chemoresistance.Expert opinion: PPIs have significant anticancer applications and are proving to be safe, effective and inexpensive. Here the authors review the current knowledge regarding the influence of PPIs on the efficacy and safety of cancer chemotherapeutics through the regulation of targets other than the H⁺/K⁺-ATPase.