Platinum-induced ototoxicity: a review of prevailing ototoxicity criteria

The Effects of Memantine on Cisplatin-Induced Ototoxicity

INTRODUCTION

We aimed to investigate electrophysiologically and histopathologically, the protective effects of intratympanic memantine, an N-methyl-D-aspartate receptor antagonist, on ototoxicity caused by cisplatin, an anti-neoplastic agent used in many types of cancer.

METHODS

Thirty-seven guinea pigs with a normal auditory function were randomly allocated to group 1 (cisplatin; n = 8), group 2 (memantine; n = 8), group 3 (cisplatin + memantine; n = 8), group 4 (cisplatin + physiological serum [PS]; n = 8), and group 5 (control; n = 5). Auditory assessments were conducted using distortion product otoacoustic emissions (DPOAE) within a frequency range of 1-32 kHz and auditory brainstem responses (ABRs) within 8-32 kHz. A single dose of cisplatin (12 mg/kg) was administered intraperitoneally, followed by intratympanic administration of 0.2 mL of either memantine or PS to both ears at least half an hour before cisplatin administration. Subsequent auditory evaluations were conducted 72 h after cisplatin administration. Histopathological analyses were performed using light microscopy of the right ear and scanning electron microscopy (SEM) of the left ear.

RESULTS

Auditory evaluations conducted before and after treatment revealed significant findings. Specifically, within groups 3 and 4, ABR thresholds were elevated at all frequencies (p = 0.00), whereas the DPOAE signal-to-noise ratios were reduced at frequencies of 8, 12, 16, and 24 kHz (p = 0.001, p = 0.01, p = 0.01, and p = 0.00, respectively). Histopathologically, both light microscopy and SEM revealed that the cisplatin + memantine group exhibited fewer hair cells and nuclear degeneration in the spiral ganglion than the cisplatin and cisplatin + PS groups. Additionally, the stria vascularis thickness was greater in the cisplatin + memantine group than in cisplatin and cisplatin + PS groups.

CONCLUSION

Despite the negative electrophysiological findings, the histopathological outcomes suggest that intratympanic memantine may have a potential protective effect against cisplatin-induced ototoxicity. However, further investigations are warranted to corroborate these findings and elucidate the underlying mechanisms of action of memantine.

Apoptosis, autophagy, ferroptosis, and pyroptosis in cisplatin-induced ototoxicity and protective agents

Cisplatin is widely used to treat various solid tumors. However, its toxicity to normal tissues limits its clinical application, particularly due to its ototoxic effects, which can result in hearing loss in patients undergoing chemotherapy. While significant progress has been made in preclinical studies to elucidate the cellular and molecular mechanisms underlying cisplatin-induced ototoxicity (CIO), the precise mechanisms remain unclear. Moreover, the optimal protective agent for preventing or mitigating cisplatin-induced ototoxicity has yet to be identified. This review summarizes the current understanding of the roles of apoptosis, autophagy, ferroptosis, pyroptosis, and protective agents in cisplatin-induced ototoxicity. A deeper understanding of these cell death mechanisms in the inner ear, along with the protective agents, could facilitate the translation of these agents into clinical therapeutics, help identify new therapeutic targets, and provide novel strategies for cisplatin-based cancer treatment.

Prevention and treatment of cisplatin-induced ototoxicity in adults: A systematic review

OBJECTIVES

Ototoxicity is a common disabling side effect of platinum-based chemotherapy. This study aimed to assess the evidence on the management of platinum-induced ototoxicity in adult cancer patients.

METHODS

Four databases were searched up to 1 November 2022. Original studies were included if they reported on a pharmacologic or non-pharmacologic intervention to prevent or treat platinum ototoxicity in adults. The articles' quality was assessed via two grading scales.

RESULTS

Nineteen randomised controlled trials and five quasi-experimental studies with 1673 patients were analysed. Eleven interventions were identified, nine pharmacological and two non-pharmacological. Six of the interventions (sodium thiosulphate, corticoids, sertraline, statins, multivitamins and D-methionine) showed mild benefits in preventing cisplatin-induced ototoxicity. Only one trial assessed corticoids as a potential treatment. Overall, only six trials were deemed with a low risk of bias. The majority of studies inadequately documented intervention-related adverse effects, thereby limiting safety conclusions.

CONCLUSIONS

Current interventions have mild benefits in preventing cisplatin-induced ototoxicity in adult cancer patients. Sodium thiosulphate is the most promising intervention as a preventive strategy. Rigorous, high-quality research is warranted, encompassing an evaluation of all potential symptoms and innovative treatment modalities.

The Chemoprotective Potentials of Alpha-lipoic Acid against Cisplatin-induced Ototoxicity: A Systematic Review

PURPOSE

Ototoxicity is one of the major adverse effects of cisplatin therapy which restrict its clinical application. Alpha-lipoic acid administration may mitigate cisplatin-induced ototoxicity. In the present study, we reviewed the protective potentials of alpha-lipoic acid against the cisplatin-mediated ototoxic adverse effects.

METHODS

Based on the PRISMA guideline, we performed a systematic search for the identification of all relevant studies in various electronic databases up to June 2022. According to the inclusion and exclusion criteria, the obtained articles (n=59) were screened and 13 eligible articles were finally included in the present study.

RESULTS

The findings of in-vitro experiments showed that cisplatin treatment significantly reduced the auditory cell viability in comparison with the control group; nevertheless, the alpha-lipoic acid co-administration protected the cells against the reduction of cell viability induced by cisplatin treatment. Moreover, the in-vivo results of the auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) tests revealed a decrease in DPOAE and an increase in ABR threshold of cisplatin-injected animals; however, it was shown that alpha-lipoic acid co-treatment had an opposite pattern on the evaluated parameters. Other findings demonstrated that cisplatin treatment could significantly induce the biochemical and histopathological alterations in inner ear cells/tissue; in contrast, alpha-lipoic acid co-treatment ameliorated the cisplatin-mediated biochemical and histological changes.

CONCLUSION

The findings of audiometry, biochemical parameters, and histological evaluation showed that alpha-lipoic acid co-administration alleviates the cisplatin-induced ototoxicity. The protective role of alpha-lipoic acid against the cisplatin-induced ototoxicity can be due to different mechanisms of anti-oxidant, anti-apoptotic, anti-inflammatory activities, and regulation of cell cycle progression.

Systematic Review and Meta-Analysis of the Influence of Genetic Variation on Ototoxicity in Platinum-Based Chemotherapy

OBJECTIVE

The objective of this meta-analysis is to evaluate the impact of genetic polymorphisms on platinum-based chemotherapy (PBC)-induced ototoxicity.

DATA SOURCES

Systematic searches of PubMed, Embase, Cochrane, and Web of Science were conducted from the inception of the databases to May 31, 2022. Abstracts and presentations from conferences were also reviewed.

REVIEW METHODS

Four investigators independently extracted data in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Differences in the prevalence of PBC-induced ototoxicity between reference and variant (i) genotypes and (ii) alleles were analyzed. The overall effect size was presented using the random-effects model as an odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

From 32 included articles, 59 single nucleotide polymorphisms on 28 genes were identified, with 4406 total unique participants. For allele frequency analysis, the A allele in ACYP2 rs1872328 was positively associated with ototoxicity (OR: 2.61; 95% CI: 1.06-6.43; n = 2518). Upon limiting to cisplatin use only, the T allele of COMT rs4646316 and COMT rs9332377 revealed significant results. For genotype frequency analysis, the CT/TT genotype in ERCC2 rs1799793 demonstrated an otoprotective effect (OR: 0.50; 95% CI: 0.27-0.94; n = 176). Excluding studies using carboplatin or concomitant radiotherapy revealed significant effects with COMT rs4646316, GSTP1 rs1965, and XPC rs2228001. Major sources of variations between studies include differences in patient demographics, ototoxicity grading systems, and treatment protocols.

CONCLUSION

Our meta-analysis presents polymorphisms that exert ototoxic or otoprotective effects in patients undergoing PBC. Importantly, several of these alleles are observed at high frequencies globally, highlighting the potential for polygenic screening and cumulative risk evaluation for personalized care.

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.

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.

Global burden of ototoxic hearing loss associated with platinum-based cancer treatment: A systematic review and meta-analysis

Platinum-based chemotherapeutic agents cisplatin and carboplatin are widely used in cancer treatment worldwide and may result in ototoxic hearing loss. The high incidence of cancer and salient ototoxic effects of platinum-based compounds pose a global public health threat. The purpose of this study was twofold. First, to estimate the prevalence of ototoxic hearing loss associated with treatment with cisplatin and/or carboplatin via a systematic review and meta-analysis. Second, to estimate the annual global burden of ototoxic hearing loss associated with exposure to cisplatin and/or carboplatin. For the systematic review, three databases were searched (Ovid Medline, Ovid Embase, and Web of Science Core Collection) and studies that reported prevalence of objectively measured ototoxic hearing loss in cancer patients were included. A random effects meta-analysis determined pooled prevalence (95% confidence intervals [CI]) of ototoxic hearing loss overall, and estimates were stratified by treatment and patient attributes. Estimates of ototoxic hearing loss burden were created with published global estimates of incident cancers often treated with platinum-based compounds and cancer-specific treatment rates. Eighty-seven records (n = 5077 individuals) were included in the meta-analysis. Pooled prevalence of ototoxic hearing loss associated with cisplatin and/or carboplatin exposure was 43.17% [CI 37.93-48.56%]. Prevalence estimates were higher for regimens involving cisplatin (cisplatin only: 49.21% [CI 42.62-55.82%]; cisplatin & carboplatin: 56.05% [CI 45.12-66.43%]) versus carboplatin only (13.47% [CI 8.68-20.32%]). Our crude estimates of burden indicated approximately one million individuals worldwide are likely exposed to cisplatin and/or carboplatin, which would result in almost half a million cases of hearing loss per year, globally. There is an urgent need to reduce impacts of ototoxicity in cancer patients. This can be partially achieved by implementing existing strategies focused on primary, secondary, and tertiary hearing loss prevention. Primary ototoxicity prevention via otoprotectants should be a research and policy priority.

Biopolymer Lipid Hybrid Microcarrier for Transmembrane Inner Ear Delivery of Dexamethasone

Dexamethasone is one of the most often used corticosteroid drugs for sensorineural hearing loss treatment, and is used either by intratympanic injection or through systemic delivery. In this study, a biopolymer lipid hybrid microcarrier was investigated for enhanced local drug delivery and sustained release at the round window membrane level of the middle ear for the treatment of sensorineural hearing loss (SNHL). Dexamethasone-loaded and dexamethasone-free microparticles were prepared using biopolymers (polysaccharide and protein, pectin and bovine serum albumin, respectively) combined with lipid components (phosphatidylcholine and Dimethyldioctadecylammonium bromide) in order to obtain a biopolymer–liposome hybrid system, with a complex structure combining to enhance performance in terms of physical and chemical stability. The structure of the microparticles was evaluated by FTIR, XRD, thermal analysis, optical microscopy, and scanning electron microscopy (SEM). The encapsulation efficiency determination and the in vitro Dexamethasone release study were performed using UV-Vis spectroscopy. The high value of encapsulation efficiency and the results of the release study indicated six days of sustained release, encouraging us to evaluate the in vitro cytotoxicity of Dexamethasone-loaded microparticles and their influence on the cytotoxicity induced by Cisplatin on auditory HEI-OC1 cells. The results show that the new particles are able to protect the inner ear sensory cells.

Association of hearing loss and tinnitus symptoms with health-related quality of life among long-term oropharyngeal cancer survivors

BACKGROUND

This study investigated the association of hearing loss and tinnitus with overall health-related quality of life (HRQoL) among long-term oropharyngeal cancer (OPC) survivors.

METHODS

This study included OPC survivors treated between 2000 and 2013 and surveyed from September 2015 to July 2016. Hearing loss and tinnitus were measured by asking survivors to rate their "difficulty with hearing loss and/or ringing in the ears" from 0 (not present) to 10 (as bad as you can imagine). Hearing loss and tinnitus scores were categorized as follows: 0 for none, 1-4 for mild, and 5-10 for moderate to severe. The primary outcome was the mean score of MD nderson Symptom Inventory Head & Neck module interference component as a HRQoL surrogate dichotomized as follows: 0 to 4 for none to mild and 5 to 10 for moderate to severe interference.

RESULTS

Among 880 OPC survivors, 35.6% (314), reported none, 39.3% (347) reported mild, and 25.1% (221) reported moderate to severe hearing loss and tinnitus. On multivariable analysis, mild (OR, 5.83; 95% CI; 1.48-22.88; p = 0.012) and moderate (OR, 30.01; 95% CI; 7.96-113.10; p < 0.001) hearing loss and tinnitus were associated with higher odds of reporting moderate to severe symptom interference scores in comparison to no hearing loss and tinnitus. This association of hearing dysfunction was consistent with all domains of HRQoL.

CONCLUSIONS

Our findings provide preliminary evidence to support the need for continued audiological evaluations and surveillance to detect hearing dysfunction, to allow for early management and to alleviate the long-term impact on QoL.

The cumulative incidence of cisplatin-induced hearing loss in young children is higher and develops at an early stage during therapy compared with older children based on 2052 audiological assessments

BACKGROUND

Ototoxicity is a common adverse event of cisplatin treatment. The authors investigated the development of cisplatin-induced hearing loss (CIHL) over time in children with cancer by age and examined the influence of other clinical characteristics on the course of CIHL.

METHODS

Data from Canadian patients with childhood cancer were retrospectively reviewed. Hearing loss was graded according to International Society of Pediatric Oncology criteria. The Kaplan-Meier method was applied to estimate the cumulative incidence of CIHL for the total cohort and according to age. Cox regression models were used to explore the effects of independent variables on CIHL development up to 3 years after the start of therapy.

RESULTS

In total, 368 patients with 2052 audiological assessments were included. Three years after initiating therapy, the cumulative incidence of CIHL was highest in patients aged ≤5 years (75%; 95% confidence interval [CI], 66%-84%), with a rapid increase observed to 27% (95% CI, 21%-35%) at 3 months and to 61% (95% CI, 53%-69%) at 1 year, compared with patients aged >5 years (48%; 95% CI, 37%-62%; P < .001). The total cumulative dose of cisplatin at 3 months (per 100 mg/m² increase: hazard ratio [HR], 1.20; 95% CI, 1.01-1.41) vincristine (HR, 2.87; 95% CI, 1.89-4.36) and the total duration of concomitantly administered antibiotics (>30 days: HR, 1.85; 95% CI, 1.17-2.95) further influenced CIHL development over time.

CONCLUSIONS

In young children, the cumulative incidence of CIHL is higher compared with that in older children and develops early during therapy. The course of CIHL is further influenced by the total cumulative dose of cisplatin and other ototoxic (co-)medication. These results highlight the need for audiological monitoring at each cisplatin cycle.

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.

Extended high frequency audiometry thresholds in healthy school children

OBJECTIVES

Extended high frequency (EHF) audiometry is the recommended method for monitoring oxotoxic hearing loss in children. This study aims to provide high quality reference audiological data for the EHF range in healthy children.

METHODS

Participants were 126 healthy schoolchildren between 6 and 14 years of age. All participants were term born with normal birthweight, had not suffered severe neonatal illness and had no history of middle ear disease.

RESULTS

The averaged mean (SD) hearing threshold for the EHF 9, 10, 11.2, 12.5, 14 and 16 kHz was -0.4 (6.0) dB HL. The lowest mean hearing thresholds were observed at 14 kHz with -4.2 (8.7) dB and at 16 kHz with -6.4 (12.1) dB HL. We found significantly lower thresholds at 16 kHz for children aged 6-9 years (-8.7 dB HL) compared to age 10-14 years (-3.9 db HL), p 0.042. For both age groups the inter-subject variability increased in the highest frequencies. We found no significant differences in mean hearing thresholds between right and left ears at any frequency, and no gender differences in the EHF range.

CONCLUSION

Our findings support that decreased hearing sensitivity in the EHF's may start around or even before the age of 10 years. In order to use EHF audiometry for ototoxic monitoring in children, we suggest to establish an international reference standard for hearing levels in children under the age of 18. Specific references for different age groups are needed as hearing in the EHF range appears to gradually deteriorate from an early age.

CLINICAL TRIAL REGISTRATION

NCT03253614.

Knockdown of sorcin increases HEI-OC1 cell damage induced by cisplatin in vitro

Hearing loss caused by ototoxic drugs is a kind of acquired hearing loss. Cisplatin is one of the most commonly used drugs and its main action sites are hair cells (HCs). Sorcin is a drug-resistant calcium-binding protein belonging to the small penta-EF-hand protein family. Sorcin is highly expressed in many tissues, including bone, heart, brain, lung, and skin tissues. Single-cell RNA sequencing showed that sorcin was expressed in the outer HCs of mice, but its role remained unknown. We also found that sorcin was highly expressed in the cytoplasm of cochlear HCs and HEI-OC1 cells. After cisplatin injury, the expression of sorcin in HCs and HEI-OC1 cells decreased significantly. SiRNA transfection technology was used to knock down the expression of sorcin. The results showed that the number of apoptotic cells, the expression of cleaved caspased-3, and the expression of Bax increased while the anti-apoptotic factor Bcl-2 decreased in the siRNA-Sorcin + CIS group. The observed increase in apoptosis was related to the increase of reactive oxygen species (ROS) and the destruction of the mitochondrial membrane potential (MMP). Finally, we found that the downregulated sorcin worked by activating the P-ERK1/2 signaling pathway. Overall, this study showed that sorcin can be used as a new target to prevent the ototoxicity of platinum drugs.

Early Physiological and Cellular Indicators of Cisplatin-Induced Ototoxicity

Cisplatin chemotherapy often causes permanent hearing loss, which leads to a multifaceted decrease in quality of life. Identification of early cisplatin-induced cochlear damage would greatly improve clinical diagnosis and provide potential drug targets to prevent cisplatin's ototoxicity. With improved functional and immunocytochemical assays, a recent seminal discovery revealed that synaptic loss between inner hair cells and spiral ganglion neurons is a major form of early cochlear damage induced by noise exposure or aging. This breakthrough discovery prompted the current study to determine early functional, cellular, and molecular changes for cisplatin-induced hearing loss, in part to determine if synapse injury is caused by cisplatin exposure. Cisplatin was delivered in one to three treatment cycles to both male and female mice. After the cisplatin treatment of three cycles, threshold shift was observed across frequencies tested like previous studies. After the treatment of two cycles, beside loss of outer hair cells and an increase in high-frequency hearing thresholds, a significant latency delay of auditory brainstem response wave 1 was observed, including at a frequency region where there were no changes in hearing thresholds. The wave 1 latency delay was detected as early cisplatin-induced ototoxicity after only one cycle of treatment, in which no significant threshold shift was found. In the same mice, mitochondrial loss in the base of the cochlea and declining mitochondrial morphometric health were observed. Thus, we have identified early spiral ganglion-associated functional and cellular changes after cisplatin treatment that precede significant threshold shift.

Usefulness of current candidate genetic markers to identify childhood cancer patients at risk for platinum-induced ototoxicity: Results of the European PanCareLIFE cohort study

BACKGROUND

Irreversible sensorineural hearing loss is a common side effect of platinum treatment with the potential to significantly impair the neurocognitive, social and educational development of childhood cancer survivors. Genetic association studies suggest a genetic predisposition for cisplatin-induced ototoxicity. Among other candidate genes, thiopurine methyltransferase (TPMT) is considered a critical gene for susceptibility to cisplatin-induced hearing loss in a pharmacogenetic guideline. The aim of this cross-sectional cohort study was to confirm the genetic associations in a large pan-European population and to evaluate the diagnostic accuracy of the genetic markers.

METHODS

Eligibility criteria required patients to be aged less than 19 years at the start of chemotherapy, which had to include cisplatin and/or carboplatin. Patients were assigned to three phenotype categories: no, minor and clinically relevant hearing loss. Fourteen variants in eleven candidate genes (ABCC3, OTOS, TPMT, SLC22A2, NFE2L2, SLC16A5, LRP2, GSTP1, SOD2, WFS1 and ACYP2) were investigated. Multinomial logistic regression was performed to model the relationship between genetic predictors and platinum ototoxicity, adjusting for clinical risk factors. Additionally, measures of the diagnostic accuracy of the genetic markers were determined.

RESULTS

900 patients were included in this study. In the multinomial logistic regression, significant unique contributions were found from SLC22A2 rs316019, the age at the start of platinum treatment, cranial radiation and the interaction term [platinum compound]∗[cumulative dose of cisplatin]. The predictive performance of the genetic markers was poor compared with the clinical risk factors.

CONCLUSIONS

PanCareLIFE is the largest study of cisplatin-induced ototoxicity to date and confirmed a role for the polyspecific organic cation transporter SLC22A2. However, the predictive value of the current genetic candidate markers for clinical use is negligible, which puts the value of clinical factors for risk assessment of cisplatin-induced ototoxicity back into the foreground.

Implantable Drug Reservoir Devices for Inner Ear Delivery of Pharmacotherapeutics

Objective

Cisplatin is a platinum-based chemotherapeutic drug that secondarily induces toxicity in inner ear sensory epithelia, contributing to auditory and vestibular dysfunction. We describe the creation of a drug reservoir device (DRD) to combat this ototoxicity for the duration of chemotherapy. As ototoxic side effects of chemotherapy may limit an oncologist’s ability to prescribe first-line agents such as cisplatin, mitigating such devastating effects through prolonged topical therapy would be tremendously valuable.

Study Design

We investigated (1) the ability of an electrospun polylactic acid DRD to provide prolonged delivery of the posited otoprotectant metformin and (2) the development of an in vitro model utilizing Sh-Sy5y human neuroblastoma cells to assess the efficacy of metformin in reducing cisplatin-induced toxicity.

Setting

Neurophysiology laboratory.

Methods

Basic science experiments were performed to assess DRD properties and metformin’s effects on cisplatin toxicity in culture.

Results

We found that DRDs with increasing polylactic acid concentrations exhibited metformin release for up to 8 weeks. In modeling elution across the round window in vitro, continued elution of metformin was observed for at least 6 weeks, as quantified by spectrophotometry. Unfortunately, metformin did not exhibit protective efficacy in this model using Sh-Sy5y cells.

Conclusion

While metformin was not found to be protective in Sh-Sy5y cells, these results suggest that an electrospun DRD can provide a tailorable drug delivery system providing medication for the duration of chemotherapy treatment. This represents a novel drug delivery system and efficacy screening assay with broad clinical applications in personalized delivery of inner ear therapies.

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.

Platinum-drugs Ototoxicity in Pediatric Patients With Brain Tumors: A 10-Year Review

PURPOSE

Platinum-derived chemotherapy is one of the cornerstones in the treatment of central nervous system tumors in children. We aimed to assess the incidence of hearing loss in children after the exposure to platinum drugs.

MATERIAL AND METHODS

Retrospective study of prospectively collected data on children consecutively diagnosed with brain tumors and treated with platinum derivatives at a tertiary referral hospital between January 2006 and December 2015. We analyzed multiples variables, such as: age at diagnosis, tumor location, hydrocephalus, platinum drug type, radiotherapy, and follow-up time. The final sample size was 51 patients.

RESULTS

The median age at diagnosis was 6 years. The median overall follow-up time was 75 months. The incidence of ototoxicity was 23.5%. Rates of hearing loss with carboplatinum were lower than with cisplatinum. A statistically significant association occurred between the presence of hydrocephalus, radiotherapy exposure, infratentorial tumor location, and ototoxicity after treatment with platinum derivatives.

CONCLUSIONS

Childhood central nervous system tumors nowadays exhibit improved cure and survival rates. However, the ototoxicity resulting from the chemotherapy treatment may accompany patients for the rest of their lives. This study reveals that this occurrence is not negligible, and the association of radiotherapy and the presence of hydrocephalus can be potentiating factors.

Effects of chemotherapy on the auditory system of children with cancer: a systematic literature review

ABSTRACT Purpose: to identify and analyze the effects of chemotherapy on the auditory system of children and/or adolescents with cancer treated with cisplatin and carboplatin, assessed through standardized audiological procedures. Methods: studies in Brazilian Portuguese and in English were searched for, as available in the databases Science Direct, PubMed, LILACS, BIREME, Embase, SciELO, Web of Science and Cochrane. The descriptors were: Hearing Loss, Audiology, Child Cancer, Chemotherapy, and Child. Articles with levels 1 and 2 of scientific evidence, published in the last 20 years (1997 to 2017), were considered, of which the audiological results were analyzed, as well as the prevalence of hearing loss in children with cancer undergoing chemotherapy. Results: 3,625 articles were found, of which only 23 were selected for analysis in the present review. Studies have shown a high incidence of sensorineural hearing loss and decrease or even loss of otoacoustic emissions in children and adolescents with cancer, even after the first dose of chemotherapy drugs, with high frequencies being the most affected. Conclusion: there is evidence that both carboplatin and especially cisplatin from the first doses may impair the hearing of children and adolescents, mainly affecting the cochlear function, thus, the importance of long-term audiological monitoring.

Overview of cisplatin-induced neurotoxicity and ototoxicity, and the protective agents

Cisplatin has dramatically improved the survival rate of cancer patients, but it has also increased the prevalence of hearing and neurological deficits in this population. Cisplatin induces ototoxicity, peripheral (most prevalent) and central (rare) neurotoxicity. This review addresses the ototoxicity and the neurotoxicity associated with cisplatin-based chemotherapy, providing an integrated view of the potential protective agents that have been evaluated in vitro, in vivo and in clinical trials, their targets and mechanisms of protection and their effects on the antitumor activity of cisplatin. So far, the findings are insufficient to support the use of any oto- or neuroprotective agent before, during or after cisplatin chemotherapy. Despite their promising effects in vitro and in animal studies, many agents have not been evaluated in clinical trials. Additionally, the clinical trials have limitations concerning the sample size, controls, measurement, heterogeneous groups, several arms of treatment, short follow-up or no blinding. Besides that, for most agents, the effects on the antitumor activity of cisplatin have not been evaluated in tumor-bearing animals, which discourages clinical trials. Further well-designed randomized controlled clinical trials are necessary to definitely demonstrate the effectiveness of the oto- or neuroprotective agents proposed by animal and in vitro studies.

Efficacy of 2 Different Intratympanic Steroid Regimen on Prevention of Cisplatin Ototoxicity: An Experimental Study

Ototoxicity is the general name of cochlear and vestibular organ injury resulting from encountering various therapeutic agents and chemical substances. Cisplatin is commonly used in the treatment of many cancers. In this study, the efficacy of intratympanic steroids was compared for preventing cisplatin ototoxicity. In this study, 32 (64 ears) rats were used by separating into 4 groups. Cisplatin was administered intraperitoneally to the first group (n = 8). Methylprednisolone and then cisplatin were administered intratympanically to the second group (n = 8). On the third group (n = 8), dexamethasone and then cisplatin were administered intratympanically. To the fourth group (n = 8), 0.9% NaCl and then cisplatin were given intratympanically. Otoacoustic emission (OAE) measurements and auditory brainstem responses (ABRs) tests were performed on all groups before and 72 hours after the procedure. Pretreatment of ABR-IV values were 4.29 ± 0.19 milliseconds in group 2 and 4.27 ± 0.16 milliseconds in group 3, whereas posttreatment ABR-IV values were 4.95 ± 0.35 milliseconds in group 2 and 4.65 ± 0.26 milliseconds in group 3. The ABR-IV values were measured significantly shorter in the rats given dexamethasone and methylprednisolone, according to control and cisplatin groups (P < .001). Pretreatment of ABR I-IV interval values were 2.98 ± 0.34 milliseconds and 3.03 ± 0.42 milliseconds in group 1 and group 4, respectively, and ABR I-IV interval values in group 1 and group 4 posttreatment were 3.49 ± 0.39 milliseconds and 3.5 ± 0.39 milliseconds in group 1 and group 4, respectively. Auditory brainstem responses I-IV interval was significantly longer in the cisplatin and control group than in the rats given dexamethasone and methylprednisolone (P < .001). After cisplatin treatment, OAE amplitudes decreased significantly in group 1 and group 4 for all frequencies, while OAE values were protected in methylprednisolone and dexamethasone group (P < .001). In conclusion, it has been shown that both agents have protective effects on cisplatin ototoxicity, with dexamethasone slightly more than methylprednisolone.

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

Objective: To identify any change in quality of life (QoL) caused by chemotherapy-induced toxicities, such as hearing loss and tinnitus, to provide information in order to improve services and aid clinicians in their decision-making. Design: This systematic review followed the preferred reporting items for systematic reviews and meta-analysis (PRISMA) checklist. The search terms were cancer, platinum-based chemotherapy, ototoxicity and "quality of life". Titles and abstracts, followed by full texts, were screened by two independent researchers. The relevant data were extracted and quality analysis was performed using the NIH Quality Assessment Tool. Study sample: About 308 titles and abstracts were screened, and 27 full-text articles were screened. Ten articles representing 11 studies were included in the review. Study design included cross-sectional studies, randomised control trials and longitudinal studies. Results: Diagnostic criteria consisted of audiograms, questionnaires and patient complaints. The study quality ranged from 21.43% to 85.71%. Overall results found that those treated with cisplatin had more hearing loss and tinnitus than those treated with other therapies. Furthermore, those with hearing loss and tinnitus were more likely to have a lower QoL. Conclusions: There is an urgent need to standardise diagnostics when investigating ototoxicity and its effect on QoL, particularly for research into risk factors, prevention and management.

Genetic Determinants of Ototoxicity During and After Childhood Cancer Treatment: Protocol for the PanCareLIFE Study

Background

Survival rates after childhood cancer now reach nearly 80% in developed countries. However, treatments that lead to survival and cure can cause serious adverse effects with lifelong negative impacts on survivor quality of life. Hearing impairment is a common adverse effect in children treated with cisplatin-based chemotherapy or cranial radiotherapy. Ototoxicity can extend from high-tone hearing impairment to involvement of speech frequencies. Hearing impairment can impede speech and language and neurocognitive development. Although treatment-related risk factors for hearing loss following childhood cancer treatment have been identified, the individual variability in toxicity of adverse effects after similar treatment between childhood cancer patients suggests a role for genetic susceptibility. Currently, 12 candidate gene approach studies have been performed to identify polymorphisms predisposing to platinum-induced ototoxicity in children being treated for cancer. However, results were inconsistent and most studies were underpowered and/or lacked replication.

Objective

We describe the design of the PanCareLIFE consortium’s work packages that address the genetic susceptibility of platinum-induced ototoxicity.

Methods

As a part of the PanCareLIFE study within the framework of the PanCare consortium, we addressed genetic susceptibility of treatment-induced ototoxicity during and after childhood cancer treatment in a large European cohort by a candidate gene approach and a genome-wide association screening.

Results

This study included 1124 survivors treated with cisplatin, carboplatin, or cranial radiotherapy for childhood cancer, resulting in the largest clinical European cohort assembled for this late effect to date. Within this large cohort we defined a group of 598 cisplatin-treated childhood cancer patients not confounded by cranial radiotherapy. The PanCareLIFE initiative provided, for the first time, a unique opportunity to confirm already identified determinants for hearing impairment during childhood cancer using a candidate gene approach and set up the first international genome-wide association study of cisplatin-induced direct ototoxicity in childhood cancer patients to identify novel allelic variants. Results will be validated in an independent replication cohort. Patient recruitment started in January 2015 and final inclusion was October 2017. We are currently performing the analyses and the first results are expected by the end of 2019 or the beginning of 2020. 

Conclusions

Genetic factors identified as part of this pan-European project, PanCareLIFE, may contribute to future risk prediction models that can be incorporated in future clinical trials of platinum-based therapies for cancer and may help with the development of prevention strategies.

International Registered Report Identifier (IRRID)

DERR1-10.2196/11868

Exploring the Experiences of Cancer Patients With Chemotherapy-Induced Ototoxicity: Qualitative Study Using Online Health Care Forums

BACKGROUND

Many cancer patients and survivors experience permanent and life-debilitating effects, such as ototoxicity, from treatment. Ototoxicity manifests as high-frequency hearing loss and tinnitus, which can have a detrimental effect on the quality of life (QoL) of those affected. Currently, there is little information and support offered to these patients who experience ototoxicity, potentially leading to many being undiagnosed and untreated.

OBJECTIVE

The aim of this study was to explore the extent of ototoxic side effects, such as hearing loss and tinnitus, and their impact on cancer patients following chemotherapy treatment. Secondary objectives included detecting the time periods of onset and duration of the ototoxicity and identifying what support was available to this population.

METHODS

Posts from publicly available online forums were thematically analyzed using the guidelines by Braun and Clarke. A coding manual was iteratively developed to create a framework for the analysis of the ototoxicity experience among the cancer population.

RESULTS

A total of 9 relevant online forums were identified, consisting of 86 threads and 570 posts from 377 members. Following the bottom-up thematic analysis, 6 major themes were identified: nature of ototoxicity, time of experienced ototoxicity, information on ototoxicity, quality of life, therapies, and online social support.

CONCLUSIONS

There was a significant number of reports expressing concerns about the lack of information on the risk of ototoxicity. More support for those suffering is needed; for example, improved interdepartmental communication between oncology and audiology services could optimize patient care. Patients should also be encouraged to communicate with their health care professionals about their ototoxicity and relay how their QoL is impacted by ototoxicity when accessing support. Tinnitus was the most common concern and was associated with distress. Hearing loss was less common; however, it was associated with fear and employment issues. Those who reported preexisting conditions were fearful about worsening their condition as their QoL was already impacted.

[Drug-induced hearing loss as a manifestation of drug-induced ototoxicity]

The ability of drugs to have an ototoxic effect has been studied for a long time, however, the true prevalence of this undesirable phenomenon is unknown, which is due to the use of various audiological protocols, a wide range of reactions to drugs in different ethnic groups, and most importantly, the lack of caution with regard to otological symptoms due to their reversibility or lack of immediate threat to life. Drug-induced ototoxicity is a functional disorder of the inner ear (cochlea and/or vestibular apparatus) or eighth pair of cranial nerves. Pharmacotherapy, associated with the development of ototoxic drug reactions, may remain undervalued for a long time, often until irreversible hearing impairment is formed. The most frequently prescribed drugs that cause ototoxic phenomena include anticancer drugs, antibacterial drugs of the aminoglycoside group, loop diuretics, calcium channel blockers, non-steroidal anti-inflammatory drugs, antimalarial drugs, salicylates, etc. Monitoring the degree of hearing impairment before and during therapy is important in preventing the development of drug-induced ototoxicity and makes it possible to consider alternative treatment regimens in a timely manner. It is in this connection that the role of participation in the appointment of rational pharmacotherapy to patients with a potential risk of developing otological phenomena of a clinical pharmacologist and audiologist undoubtedly increases.

Drug-Induced Ototoxicity: Diagnosis and Monitoring

Ototoxicity diagnosis and management has historically been approached using a variety of methods. However, in recent years a consensus on useful and practical approaches has been developed through clinical guidelines of the American Speech Language Hearing Association, the American Academy of Audiology, and multiple clinical trials published in peer-reviewed literature. Some of the guidelines and approaches are used to detect and monitor ototoxicity, while others are used to grade adverse events. Some of the audiologic measures are primary, while others are adjunct measures and may be tailored to the specific needs of the patient or clinical trial. For some types of monitoring, such as drug-induced tinnitus or dizziness, validated paper survey instruments can be both sensitive and easy for fragile patients. This review addresses the characteristics of some of the most common clinical ototoxins and the most common methods for detecting and monitoring ototoxicity in clinical practice and clinical trials.

Age-corrected hearing loss after chemoradiation in cervical cancer patients

OBJECTIVE

This study aimed to evaluate subjective and objective hearing loss in cervical cancer patients after chemoradiation with cisplatin (mono).

PATIENTS AND METHODS

A total of 51 cervical cancer patients with indication for chemoradiation were included. Pure tone and impedance audiometry were performed before and after chemoradiation. Hearing loss was scaled according to ASHA criteria. Subjective hearing was assessed with the Oldenburger Sentence Test. To consider age-dependent changes, hearing loss was corrected for age and the time interval between measurements.

RESULTS

Median age at diagnosis was 46 years, 46% were active/former smokers (n = 24), 28 (54%) patients were never-smokers. Median total weekly cisplatin dose was 70 ± 14.2 mg. Cumulative doses of cisplatin during chemoradiation ranged between 115.2 and 400 mg cisplatin (mean 336.1 mg, median 342 ± 52.7 mg). The median interval between last chemotherapy and second audiometry was 320 ± 538 days (35-2262 days). Changes in hearing threshold ≥20 dB were experienced by 32/52 patients (62%) following chemoradiation, 55% of them for frequencies ≥6000 Hz. No statistically significant hearing loss remained after chemoradiation upon correction for age and time interval. Patients >40 years had a higher risk of hearing loss than younger patients. Objective data on hearing function did not correlate with subjective hearing loss and did not impair daily activity in any patient.

CONCLUSION

Chemoradiation with cumulative cisplatin doses up to 400 mg did not lead to significant impairment of objective or subjective hearing. For cervical cancer patients undergoing chemoradiation, standard audiometry is not indicated.

Hearing loss before and after cisplatin-based chemotherapy in testicular cancer survivors: a longitudinal study

BACKGROUND

Hearing loss is a well-known long-term effect after cisplatin-based chemotherapy (CBCT) in testicular cancer survivors (TCS), but longitudinal data are sparse. We evaluate hearing loss and the impact of age in TCS treated with CBCT in this longitudinal study.

MATERIAL AND METHODS

Forty-six TCS treated with CBCT 1980-1994 with audiograms (0.25-8 kHz) pre-chemotherapy (PRE) and at a follow-up survey (SURV) after median 10 years were included (cases). Audiograms at SURV from 46 age-matched TCS without CBCT were included as controls. Linear regression was performed to evaluate predictors for change in the hearing threshold level (HTL) from PRE to SURV. Two definitions of a audiogram-defined hearing loss was applied if: (1) mean HTL for both ears exceeded 20 dB at any frequency 0.25-8 kHz (American Speech-Language-Hearing Association (ASHA) definition) and (2) average HTL for the frequencies 0.5, 1, 2 and 4 kHz exceeded 20 dB (WHO-M4 definition). Self-reported hearing impairment (SURV) was assessed by a questionnaire.

RESULTS

Age and cisplatin dose was significantly associated with a greater change in HTL for the frequencies 2-8 kHz. For the 8 kHz frequency, each 100 mg increase in cumulative cisplatin dose was associated with a deterioration of 3.6 dB (95% CI 1.8-5.3, p < .001). The prevalence of hearing loss (ASHA) among cases was 33% PRE, 70% at SURV and 65% among controls at SURV (cases vs. controls, p = .66). According to M4, the prevalence of hearing loss among cases was 6.5% PRE, 13% at SURV and 2.2% among controls at SURV (cases vs. controls, p = .049). Twenty-nine percent of cases, and 33% of controls (p = .70) reported hearing impairment at SURV.

CONCLUSION

Cisplatin is associated with a hearing loss particularly at higher frequencies. Age appear to be an important factor for hearing loss regardless of treatment. The ASHA definition overestimates the hearing problem.

Associations Between Perceived Stress and Chemotherapy-Induced Peripheral Neuropathy and Otoxicity in Adult Cancer Survivors

CONTEXT

The most common adverse effects from neurotoxic chemotherapy are chemotherapy-induced neuropathy (CIPN), hearing loss, and tinnitus. Although associations between perceived stress and persistent pain, hearing loss, and tinnitus are documented, no studies have examined these associations in cancer survivors who received neurotoxic chemotherapy.

OBJECTIVES

In this cross-sectional study, we evaluated for associations between perceived stress and the occurrence of CIPN, hearing loss, and tinnitus, in 623 adult cancer survivors who received platinum and/or taxane compounds.

METHODS

Survivors completed self-report measures of hearing loss, tinnitus, and perceived stress (i.e., Impact of Events Scale-Revised [IES-R]). Separate logistic regression analyses were done for each neurotoxicity to evaluate whether each of the IES-R subscale (i.e., intrusion, avoidance, hyperarousal) and total scores made a significant independent contribution to neurotoxicity group membership.

RESULTS

Of the 623 survivors in this study, 68.4% had CIPN, 34.5% reported hearing loss, and 31.0% reported tinnitus. Older age, higher body mass index, poorer functional status, being born prematurely, cancer diagnosis, and higher intrusion (P = 0.013), hyperarousal (P = 0.014), and total (P = 0.047) IES-R scores were associated with CIPN. Older age, being male, poorer functional status, a worse comorbidity profile, and a higher IES-R hyperarousal (P = 0.007) score were associated with hearing loss. Being male, having less education, a worse comorbidity profile, and a higher IES-R hyperarousal (P = 0.029) score were associated with tinnitus.

CONCLUSION

These findings suggest that increased levels of perceived stress are associated with the most common chemotherapy-induced neurotoxicities.

Prevention of cisplatin-induced hearing loss in children: Informing the design of future clinical trials

Cisplatin is an essential chemotherapeutic agent in the treatment of many pediatric cancers. Unfortunately, cisplatin-induced hearing loss (CIHL) is a common, clinically significant side effect with life-long ramifications, particularly for young children. ACCL05C1 and ACCL0431 are two recently completed Children's Oncology Group studies focused on the measurement and prevention of CIHL. The purpose of this paper was to gain insights from ACCL05C1 and ACCL0431, the first published cooperative group studies dedicated solely to CIHL, to inform the design of future pediatric otoprotection trials. Use of otoprotective agents is an attractive strategy for preventing CIHL, but their successful development must overcome a unique constellation of methodological challenges related to translating preclinical research into clinical trials that are feasible, evaluate practical interventions, and limit risk. Issues particularly important for children include use of appropriate methods for hearing assessment and CIHL severity grading, and use of trial designs that are well-informed by preclinical models and suitable for relatively small sample sizes. Increasing interest has made available new funding opportunities for expanding this urgently needed research.

An evaluation of hearing in infants administered with colistin in the premature neonatal intensive care unit

AIM

The aim of this study was to investigate the effects of colistin on hearing by evaluating the otoacoustic emission tests and clinical auditory brainstem responses in preterm infants treated with colistin in the neonatal intensive care unit.

METHOD

The study included 30 neonates (male: n = 16, female: n = 14) born before 37 weeks who were admitted to the Neonatal Intensive Care Unit at the Kahramanmaras Sutcu Imam Medical Faculty between January 2014 and January 2015 and who were treated with colistin during their time in intensive care because of infection. A control group was formed consisting of 30 preterm infants (male: n = 18, female: n = 12) with no additional disease born in the hospital during the same period. Following an ear, nose and throat examination the distortion product otoacoustic emission test, transient evoked otoacoustic emission and clinical auditory brainstem response tests were applied to all 60 patients.

RESULTS

The otoacoustic emission responses obtained from the control group were positive and clinical auditory brainstem responses up to 15 dB were obtained. In the colistin group negative otoacoustic emission responses were obtained in two patients unilaterally and in one patient bilaterally and loss was observed at the thresholds in the clinical auditory brainstem response test. Significantly prolonged fifth wave latency was observed in the colistin group compared to the control group for the clinical auditory brainstem response at 15 dB.

CONCLUSIONS

Given that the study results showed unilateral hearing loss in two patients and bilateral hearing loss in one as well as latency at 15 dB, hearing tests to check for ototoxicity are recommended for patients given colistin.

Clinical and genetic associations for carboplatin-related ototoxicity in children treated for retinoblastoma: A retrospective noncomparative single-institute experience

BACKGROUND

Children with retinoblastoma treated with carboplatin chemotherapy risk moderate to severe, irreversible hearing loss. Based on published evidence, we hypothesized that ototoxicity risk is associated with clinical parameters and variants in candidate genes in drug metabolism pathways (methyltransferases [thiopurine S-methyltransferase, TPMT] and [catechol-O-methyltransferase, COMT], and drug transporter ABCC3).

PROCEDURE

We retrospectively reviewed clinical records of patients with retinoblastoma treated with carboplatin chemotherapy regarding age (at diagnosis and chemotherapy initiation), chemotherapy sessions (cycles number, drug doses, and cumulative carboplatin dose), and hearing loss (defined as ototoxicity ≥grade 2 by at least one classification system). Blood samples were genotyped for genetic variants in TPMT (rs12201199, rs1800460), COMT (rs4646316, rs9332377), and ABCC3 (rs1051640) by quantitative PCR and confirmed by allele-specific PCR. Univariate statistical tests, receiver-operating characteristic analysis, and Kaplan-Meier curves were used to examine the association between hearing loss, clinical factors, and variants in candidate genes.

RESULTS

Audiometric data and stored DNA were available for 71 patients with retinoblastoma (88% carried an RB1 pathogenic variant allele). Median carboplatin cumulative dose was 1,400 mg/m² (260-5,148 mg/m² ). Ototoxicity occurred in 18 patients (25%), strongly associated with age at diagnosis (P = 0.01) and age at chemotherapy initiation (OR = 4.99, P = 0.008). The highest likelihood ratio of hearing loss was associated with chemotherapy initiation <4.25 months of age. Ototoxicity was not associated with any tested genetic variants.

CONCLUSIONS

We observed a 25% prevalence of ototoxicity in patients with retinoblastoma treated with carboplatin, higher than previously published. Age at chemotherapy initiation was associated with carboplatin-induced ototoxicity, with children <4.25 months of age at highest risk.

Evaluation of efficacy and safety for Brucea javanica oil emulsion in the control of the malignant pleural effusions via thoracic perfusion

Background

Brucea javanica oil emulsion (BJOE) is traditional Chinese medicine with implicated anti-tumor activity, which has been used for treating lung cancer in China. The aim of this investigation was to evaluate the effects and safety of intrapleural injection of BJOE in treating malignant pleural effusion (MPE).

Methods

The randomised controlled trials (RCTs) on the effects and safety of BJOE in treating MPE were searched from electronic medical database including MEDLINE, SCI, EMBASE, Cochrance Library and CNKI. A total of 14 RCTs with 1085 patients were involved in this meta-analysis.

Results

The overall response rate (ORR) of traditional chemotherapy drugs plus BJOE was higher than that of traditional chemotherapy drugs alone (p = 0.001; odds ratio = 1.39). Meanwhile, the combination of BJOE and traditional chemotherapy drugs improved the quality of life (QOL) of patients with MPE (p < 0.001; odds ratio = 1.56) compared with traditional chemotherapy drugs alone. Moreover, the participation of BJOE reduced the myelotoxicity and digestive reactions caused by traditional chemotherapy drugs (p < 0.05).

Conclusions

The efficacy and safety of traditional chemotherapy drugs plus BJOE was superior to traditional chemotherapy drugs alone via intrapleural injection in controlling MPE, which suggested that BJOE can be used to treat MPE.

Pantoprazole, an Inhibitor of the Organic Cation Transporter 2, Does Not Ameliorate Cisplatin-Related Ototoxicity or Nephrotoxicity in Children and Adolescents with Newly Diagnosed Osteosarcoma Treated with Methotrexate, Doxorubicin, and Cisplatin

Lessons Learned.

Using a randomized crossover design and continuous variables such as change in hearing threshold and biomarkers of acute renal injury as short‐term endpoints, it was determined that pantoprazole, an organic cation transporter 2 inhibitor, did not ameliorate cisplatin‐associated nephrotoxicity or ototoxicity.

Cystatin C is a robust method to estimate glomerular filtration rate in patients with cancer. Using a patient‐reported outcome survey, all patients identified tinnitus and subjective hearing loss occurring “at least rarely” after cycle 1, prior to objective high‐frequency hearing loss measured by audiograms.

New therapies that improve outcome with less acute and long‐term toxicity are needed.

Background.

Organic cation transporter 2 (OCT2), which is a cisplatin uptake transporter expressed on renal tubules and cochlear hair cells but not on osteosarcoma cells, mediates cisplatin uptake. Pantoprazole inhibits OCT2 and could ameliorate cisplatin ototoxicity and nephrotoxicity. Using a randomized crossover design, we evaluated audiograms, urinary acute kidney injury (AKI) biomarkers, and glomerular filtration rate (GFR) estimated from cystatin C (GFR_cysC) in patients receiving cisplatin with and without pantoprazole.

Materials and Methods.

Cisplatin (60 mg/m² × 2 days per cycle) was administered concurrently with pantoprazole (intravenous [IV], 1.6 mg/kg over 4 hours) on cycles 1 and 2 or cycles 3 and 4 in 12 patients with osteosarcoma (OS) with a median (range) age of 12.8 (5.6–19) years. Audiograms, urinary AKI biomarkers, and serum cystatin C were monitored during each cycle.

Results.

Pantoprazole had no impact on decrements in hearing threshold at 4–8 kHz, post‐treatment elevation of urinary AKI biomarkers, or GFR_cysC (Fig. 1, Table 1). Histological response (percent necrosis) after two cycles was similar with or without pantoprazole. All eight patients with localized OS at diagnosis are alive and in remission; three of four patients with metastases at diagnosis have died.

Conclusion.

Pantoprazole did not ameliorate cisplatin ototoxicity or nephrotoxicity. The decrease in GFR_cysC and increase in N‐acetyl‐ß‐glucosaminidase (NAG) and creatinine demonstrate that these biomarkers can quantify cisplatin glomerular and proximal tubular toxicity. OCT2 inhibition by pantoprazole did not appear to alter antitumor response or survival.

Pharmacogenetics of drug-induced ototoxicity caused by aminoglycosides and cisplatin

Aminoglycosides and the anticancer drug cisplatin can cause permanent hearing loss, which impacts patients' quality of life and results in considerable subsequent costs. Since patients' individual susceptibility to aminoglycoside- and cisplatin-induced ototoxicity varies considerably, strategies are needed to identify patients at risk, who may require alternative treatments or specific protection strategies. For both drugs, various genetic variants were linked to an increased or decreased risk for ototoxicity. Except for the association between the A1555G mitochondrial DNA mutation and aminoglycoside ototoxicity, their evidence is considered low because study cohorts were often small and replication studies either missing or contradictory. This review summarizes the pharmacogenetic markers linked to aminoglycoside- or cisplatin-induced ototoxicity and discusses reasons for replication failure and future perspective.

Marine Sponge Natural Products with Anticancer Potential: An Updated Review

Despite the huge investment into research and the significant effort and advances made in the search for new anticancer drugs in recent decades, cancer cure and treatment continue to be a formidable challenge. Many sources, including plants, animals, and minerals, have been explored in the oncological field because of the possibility of identifying novel molecular therapeutics. Marine sponges are a prolific source of secondary metabolites, a number of which showed intriguing tumor chemopreventive and chemotherapeutic properties. Recently, Food and Drug Administration-approved drugs derived from marine sponges have been shown to reduce metastatic breast cancer, malignant lymphoma, and Hodgkin's disease. The chemopreventive and potential anticancer activity of marine sponge-derived compounds could be explained by multiple cellular and molecular mechanisms, including DNA protection, cell-cycle modulation, apoptosis, and anti-inflammatory activities as well as their ability to chemosensitize cancer cells to traditional antiblastic chemotherapy. The present article aims to depict the multiple mechanisms involved in the chemopreventive and therapeutic effects of marine sponges and critically explore the limitations and challenges associated with the development of marine sponge-based anticancer strategy.

Pharmacogenetic variants in TPMT alter cellular responses to cisplatin in inner ear cell lines

Cisplatin is a highly-effective and widely-used chemotherapeutic agent that causes ototoxicity in many patients. Pharmacogenomic studies of key genes controlling drug biotransformation identified variants in thiopurine methyltransferase (TPMT) as predictors of cisplatin-induced ototoxicity, although the mechanistic basis of this interaction has not been reported. Expression constructs of TPMT*3A, *3B and *3C variants were generated and monitored in cultured cells. Cellular TPMT*3A levels were detected at >20-fold lower amounts than the wild type confirming the unstable nature of this variant. The expression of wild type TPMT (TPMT*1) in two murine ear cell lines, HEI-OC1 and UB/OC-1, significantly mitigated their susceptibility to cisplatin toxicity. Cisplatin treatment induced Tlr4 gene expression in HEI-OC1 cells and this response was blunted by the expression of wild type TPMT but not TPMT*3A. In line with the significant mitigation of TPMT*1-expressing cells to cisplatin cytotoxicity, these findings demonstrate a drug-gene interaction between increased TPMT activity and decreased susceptibility to cisplatin-induced toxicity of inner ear cells.