Risk factors for cisplatin-associated ototoxicity in pediatric oncology patients

Gynecologic cancers in pregnancy: guidelines based on a third international consensus meeting

We aimed to provide comprehensive protocols and promote effective management of pregnant women with gynecological cancers. New insights and more experience have been gained since the previous guidelines were published in 2014. Members of the International Network on Cancer, Infertility and Pregnancy (INCIP), in collaboration with other international experts, reviewed existing literature on their respective areas of expertise. Summaries were subsequently merged into a manuscript that served as a basis for discussion during the consensus meeting. Treatment of gynecological cancers during pregnancy is attainable if management is achieved by collaboration of a multidisciplinary team of health care providers. This allows further optimization of maternal treatment, while considering fetal development and providing psychological support and long-term follow-up of the infants. Nonionizing imaging procedures are preferred diagnostic procedures, but limited ionizing imaging methods can be allowed if indispensable for treatment plans. In contrast to other cancers, standard surgery for gynecological cancers often needs to be adapted according to cancer type and gestational age. Most standard regimens of chemotherapy can be administered after 14 weeks gestational age but are not recommended beyond 35 weeks. C-section is recommended for most cervical and vulvar cancers, whereas vaginal delivery is allowed in most ovarian cancers. Breast-feeding should be avoided with ongoing chemotherapeutic, endocrine or targeted treatment. More studies that focus on the long-term toxic effects of gynecologic cancer treatments are needed to provide a full understanding of their fetal impact. In particular, data on targeted therapies that are becoming standard of care in certain gynecological malignancies is still limited. Furthermore, more studies aimed at the definition of the exact prognosis of patients after antenatal cancer treatment are warranted. Participation in existing registries (www.cancerinpregnancy.org) and the creation of national tumor boards with multidisciplinary teams of care providers (supplementary Box S1, available at Annals of Oncology online) is encouraged.

Advances in Toxicological Research of the Anticancer Drug Cisplatin

Cisplatin is one of the most widely used chemotherapeutic agents for various solid tumors in the clinic due to its high efficacy and broad spectrum. The antineoplastic activity of cisplatin is mainly due to its ability to cross-link with DNA, thus blocking transcription and replication. Unfortunately, the clinical use of cisplatin is limited by its severe, dose-dependent toxic side effects. There are approximately 40 specific toxicities of cisplatin, among which nephrotoxicity is the most common one. Other common side effects include ototoxicity, neurotoxicity, gastrointestinal toxicity, hematological toxicity, cardiotoxicity, and hepatotoxicity. These side effects together reduce the life quality of patients and require lowering the dosage of the drug, even stopping administration, thus weakening the treatment effect. Few effective measures exist clinically against these side effects because the exact mechanisms of various side effects from cisplatin remain still unclear. Therefore, substantial effort has been made to explore the complicated biochemical processes involved in the toxicology of cisplatin, aiming to identify effective ways to reduce or eradicate its toxicity. This review summarizes and reviews the updated advances in the toxicological research of cisplatin. We anticipate to provide insights into the understanding of the mechanisms underlying the side effects of cisplatin and designing comprehensive therapeutic strategies involving cisplatin.

A Review of Cisplatin-Associated Ototoxicity

Cisplatin, an effective antineoplastic drug used in the treatment of many cancers, has ototoxic potential, thus placing cancer patients, receiving this treatment, at risk of hearing loss. It is therefore important for health care professionals managing these patients to be aware of cisplatin's ototoxic properties and its clinical signs to identify patients at risk of developing a hearing impairment. Eighty-five English peer-reviewed articles and two books, from January 1975 to July 2015, were identified from PubMed, ScienceDirect, and EBSCOhost. An overview of cisplatin-associated ototoxicity, namely its clinical features, incidence rates, molecular and cellular mechanisms, and risk factors, is presented in this article. This review further highlights the importance of a team-based approach to complement an audiological monitoring program in reducing any further loss in the quality of life of affected patients, as there is currently no otoprotective agent routinely recommended for the prevention of cisplatin-associated ototoxicity.

Mechanisms of Cisplatin-Induced Ototoxicity and Prevention

Cisplatin is a highly effective antineoplastic agent used to treat solid tumors. Unfortunately, the administration of this drug leads to significant side effects, including ototoxicity, nephrotoxicity, and neurotoxicity. This review addresses the mechanisms of cisplatin-induced ototoxicity and various strategies tested to prevent this distressing adverse effect. The molecular pathways underlying cisplatin ototoxicity are still being investigated. Cisplatin enters targeted cells in the cochlea through the action of several transporters. Once it enters the cochlea, cisplatin is retained for months to years. It can cause DNA damage, inhibit protein synthesis, and generate reactive oxygen species that can lead to inflammation and apoptosis of outer hair cells, resulting in permanent hearing loss. Strategies to prevent cisplatin ototoxicity have utilized antioxidants, transport inhibitors, G-protein receptor agonists, and anti-inflammatory agents. There are no FDA-approved drugs to prevent cisplatin ototoxicity. It is critical that potential protective agents do not interfere with the antitumor efficacy of cisplatin.

Retrospective Analysis of Childhood Hepatoblastoma in a Single Centre in China

AIMS

To investigate the protocol efficacy and prognostic factors for paediatric hepatoblastoma in a multidisciplinary model in our centre.

MATERIALS AND METHODS

Consecutive hepatoblastoma patients (<18 years old) treated at Shanghai Children's Medical Center in China from August 2011 to October 2017 were analysed retrospectively for clinical features, chemotherapy courses, surgical treatment and outcomes.

RESULTS

One hundred and four cases of paediatric hepatoblastoma (64 males, 40 females; median age at diagnosis 1.64 years) had a median follow-up of 30.68 months (range 8.3-73.3 months). First complete remission was achieved in 95 cases, 85 of which achieved continuous complete remission. Another three cases were lost to follow-up after a median of 24.73 months in complete remission. Seven cases relapsed later, with two achieving a second complete remission and four deaths. Nine cases did not achieve complete remission and five of them died. In general, the 5-year overall survival rate and 5-year event-free survival (EFS) rate were 86.3 ± 5.0% and 81.8 ± 4.3%, respectively. Thirty-two cases were classified as standard risk and 72 as high risk with 5-year EFS of 96.8 ± 3.2% and 75.7 ± 5.7% (P = 0.029) and 5-year overall survival of 100% and 80.5 ± 7.0%, respectively. The mean platelet count (P = 0.0036), lactate dehydrogenase (P = 0.0443) and ferritin level (P = 0.0006) at diagnosis were much higher in the high-risk group than in the standard-risk group. Univariate analysis showed that patients <5 years of age (P = 0.018), with higher α-fetoprotein (AFP) level (>100 ng/ml, P = 0.008), without metastases at diagnosis (P = 0.001) and postoperative AFP recovery after no more than three chemocycles (P = 0.014) had better overall survival. In addition, the above factors, except metastases at diagnosis and risk group, were associated with prognosis in the multivariate analysis.

CONCLUSIONS

The result of this protocol had similar overall survival and EFS rates compared with those in developed countries. Normal postoperative AFP levels after three chemocycles has prognostic value.

The genetic vulnerability to cisplatin ototoxicity: a systematic review

Ototoxicity is one of the major side-effects of platinum-based chemotherapy, in particular cisplatin (cis-diammine dichloroplatinum II). To our knowledge, no systematic review has previously provided a quantitative summary estimate of the impact of genetics upon the risk of developing hearing loss. We searched Embase, Medline, ASSIA, Pubmed, Scopus, and Web of Science, for studies documenting the genetic risk of ototoxicity in patients with cancer treated with cisplatin. Titles/abstracts and full texts were reviewed for inclusion. Meta-analytic estimates of risk (Odds Ratio) from the pooled data were calculated for studies that have been repeated twice or more. The search identified 3891 papers, of which 30 were included. The majority were retrospective (44%), ranging from n = 39 to n = 317, some including only patients younger than 25 years of age (33%), and some on both genders (80%). The most common cancers involved were osteosarcoma (53%), neuroblastoma (37%), prostate (17%) and reproductive (10%). Most studies performed genotyping, though only 5 studies performed genome-wide association studies. Nineteen single-nucleotide polymorphisms (SNPs) from 15 genes were repeated more than twice. Meta-analysis of group data indicated that rs1872328 on ACYP2, which plays a role in calcium homeostasis, increases the risk of ototoxicity by 4.61 (95% CI: 3.04-7.02; N = 696, p < 0.0001) as well as LRP2 rs4668123 shows a cumulated Odds Ratio of 3.53 (95% CI: 1.48-8.45; N = 118, p = 0.0059), which could not be evidenced in individual studies. Despite the evidence of heterogeneity across studies, these meta-analytic results from 30 studies are consistent with a view of a genetic predisposition to platinum-based chemotherapy mediated ototoxicity. These new findings are informative and encourage the genetic screening of cancer patients in order to identify patients with greater vulnerability of developing hearing loss, a condition having a potentially large impact on quality of life. More studies are needed, with larger sample size, in order to identify additional markers of ototoxic risk associated with platinum-based chemotherapy and investigate polygenic risks, where multiple markers may exacerbate the side-effects.

Cisplatin-induced Ototoxicity in Children With Solid Tumor

Cisplatin is the principal chemotherapeutic agent and also tremendously increases the survival for pediatric patients with neuroblastoma or hepatoblastoma. With the extended overall survival period, clinical medical workers and parents gradually attach more attention to the late effect of chemotherapy of these children. The purpose of this study is to analyze the incidence and risk factors of cisplatin-based hearing loss. We retrospectively collected the archives of cisplatin-based chemotherapy and audiometric evaluation from 2005 through 2017 at Xinhua Hospital. From 384 patients treated with cisplatin, full data of 59 patients were available, and 14 cases (23.7%) were identified as significant hearing loss. The median time from usage of platinum compounds to the most recent audio test was 406 days. Cumulative and single maximum cisplatin dose was 622.6±283.2 and 137.6±51.6 mg/m/cycle, respectively. Accumulated cisplatin dose (95% confidence interval, 1.001-1.006; P=0.012) and single maximum cisplatin dose (95% confidence interval, 1.000-1.029; P=0.049) were independently important predictors for moderate to severe hearing loss in children treated with cisplatin. Cisplatin can cause ototoxicity which profoundly handicap language development and social communication for children. Regular audiological management and long-term follow-up are strongly recommended for this vulnerable group.

Contribution of the GSTP1 c.313A>G variant to hearing loss risk in patients exposed to platin chemotherapy during childhood

BACKGROUND AND AIM

Ototoxicity is a potential adverse effect of chemotherapy with platin drugs, such as cisplatin and carboplatin, in children. Hearing loss (HL) affecting frequencies below 4 kHz can compromise speech perception. The aim of this study was to investigate whether genetic variants previously implicated in ototoxicity are associated with HL overall and HL below 4 kHz in pediatric oncology patients treated with cisplatin or carboplatin.

MATERIALS AND METHODS

Patients given cisplatin or carboplatin for a pediatric cancer at least 5 years prior to the start of the study were enrolled. The patients underwent comprehensive audiological evaluations and genotyping to detect the presence of the GJB2 c.35delG, GSTP1 c.313A>G, and MT-RNR1 m.1555A>G polymorphisms.

RESULTS

HL was identified in 31/61 patients (50.8%), including 28/42 treated with cisplatin (66.6%) and 3/19 treated with carboplatin (15.8%). HL was associated with higher mean doses of cisplatin (p = .002) and carboplatin (p = .010). The c.313A>G variant of GSTP1 (heterozygous or homozygous) was detected in 31/61 patients (50.8%). An association between this variant allele and HL involving frequencies ≤ 4 kHz was identified (p = .020; 10-fold vs. non-carriers). No associations with HL were observed for GJB2 or MT-RNR1 gene variants.

CONCLUSION

The GSTP1 c.313A>G variant may increase the risk of low-frequency HL in pediatric oncology patients treated with cisplatin or carboplatin chemotherapy.

Genetic and Modifiable Risk Factors Contributing to Cisplatin-induced Toxicities

Effective administration of traditional cytotoxic chemotherapy is often limited by off-target toxicities. This clinical dilemma is epitomized by cisplatin, a platinating agent, which has potent antineoplastic activity due to its affinity for DNA and other intracellular nucleophiles. Despite its efficacy against many adult-onset and pediatric malignancies, cisplatin elicits multiple off-target toxicities that can not only severely impact a patient's quality of life but also lead to dose reductions or the selection of alternative therapies that can ultimately affect outcomes. Without an effective therapeutic measure by which to successfully mitigate many of these symptoms, there have been attempts to identify a priori those individuals who are more susceptible to developing these sequelae through studies of genetic and nongenetic risk factors. Older age is associated with cisplatin-induced ototoxicity, neurotoxicity, and nephrotoxicity. Traditional genome-wide association studies have identified single-nucleotide polymorphisms in ACYP2 and WFS1 associated with cisplatin-induced hearing loss. However, validating associations between specific genotypes and cisplatin-induced toxicities with enough stringency to warrant clinical application remains challenging. This review summarizes the current state of knowledge with regard to specific adverse sequelae following cisplatin-based therapy, with a focus on ototoxicity, neurotoxicity, nephrotoxicity, myelosuppression, and nausea/emesis. We discuss variables (genetic and nongenetic) contributing to these detrimental toxicities and currently available means to prevent or treat their occurrence.

Incidence and associated risk factors for platinum-induced ototoxicity in pediatric patients

OBJECTIVES

Platinum-based chemotherapy is effective against a variety of pediatric malignancies. Unfortunately, the use of cisplatin and carboplatin can lead to permanent and progressive sensorineural hearing loss which can affect the quality of life of cancer survivors. The objectives of this study were to evaluate the incidence of platinum-induced ototoxicity in children and analyze potential risk factors.

METHODS

Prospective cohort study. All pediatric patients receiving chemotherapy with cisplatin and/or carboplatin from 01/2012 until 10/2017 were included. Hearing evaluations were performed before every chemotherapy cycle, and following the end of chemotherapy, with auditory brainstem response, otoacoustic emissions and/or audiometry. Demographics, cumulative doses, cranial irradiation and exposure to other ototoxic agents were analyzed.

RESULTS

Twenty-eight patients were included, with a mean age of 7.2 years at the beginning of chemotherapy (range 5 months-15 years 2 months); twenty-one patients received cisplatin, four received carboplatin, and three received both agents. Twelve patients had cranial irradiation and seven received another ototoxic medication. The most frequent malignancies were germ cell tumors, medulloblastoma and gliomas. Sensorineural hearing loss occurred in 28.6% of the patients with a mean follow-up period of 21.5 months (range: 1-53 months). All patients evaluated with audiometry had ≥ Chang 2b ototoxicity. Risk factors include age less than 5 years, cranial irradiation, and cisplatin cumulative dose greater than 400 mg/m².

CONCLUSION

Sensorineural hearing loss is a potential side effect of platinum-based chemotherapy. Pediatric patients receiving cisplatin chemotherapy with a cumulative dose exceeding 400 mg/m², cranial irradiation as well as patients younger than 5 years are at greater risk of developing hearing loss.

High incidence of cisplatin-induced ototoxicity in paediatric patients in the Western Cape, South Africa

Background: Fourteen million new cancer cases are reported annually, and up to 10% of those involve children below 15 years. Cisplatin, a commonly used anti-cancer drug for its high success rate, is associated with ototoxicity. Cisplatin-induced ototoxicity is characterised by permanent bilateral severe-to-profound hearing loss. Hearing loss, when occurring during childhood, can impact negatively communication development, scholastic performance and quality of life.Aim: To determine the incidence of cisplatin-induced ototoxicity in paediatric oncology.Setting: A retrospective records review of paediatric oncology patients who underwent cisplatin-based chemotherapy and had ototoxicity monitoring from January 2015 to December 2017 at a children’s hospital.Method: Data collected included demographic, cisplatin treatment and audiometric information. The data were analysed using descriptive and inferential statistics.Results: A total of 49 records meeting the inclusion criteria were reviewed. Ototoxic hearing loss was found in 39 (80%) of the patients whose records were reviewed and the majority (56%) presented with a bilateral moderate-to-severe sensorineural hearing loss. Distortion product otoacoustic emissions were absent in 32 (67%) patients. Cumulative dose (> 200 mg/m2) was associated with higher incidences of ototoxicity (odds ratio [OR]: 1.81; 95% confidence interval [CI]: 0.67–17.34; p = 0.044). Younger patients (< 10 years) had higher odds of developing ototoxicity, but this was not statistically significant (OR: 4.00; 95% CI: 0.82–19.46; p = 0.085).Conclusion: This study found a high incidence of cisplatin-induced ototoxicity in paediatric oncology patients. This is concerning because hearing loss during this age can have long-term negative impact on a child’s development and overall quality of life. Early identification of ototoxicity-induced hearing loss and appropriate intervention are highly recommended in this patient group.

Association between genetic polymorphisms and platinum-induced ototoxicity in children

Platinum is extensively used in the treatment of several childhood cancers. However, ototoxicity is one of the most notable adverse effects, especially in children. Several studies suggest that genetics may predict its occurrence. Here, polymorphisms associated with platinum-induced ototoxicity were selected from the literature and were investigated in a pediatric population treated with platinum-based agents. In this retrospective study, patients treated with cisplatin and/or carboplatin were screened. The patients with pre- and post-treatment audiogram (Brock criteria) available were included. We selected polymorphisms that have previously been associated with cisplatin ototoxicity with a minor allele frequency ≥30%. Deletion of GSTM1 and GSTT1, rs1799735 (GSTM3), rs1695 (GSTP1), rs4880 (SOD2), rs2228001 (XPC), rs1799793 (XPD) and rs4788863 (SLC16A5) were investigated. Data of one hundred and six children matching the eligible criteria were analyzed. Thirty-three patients (31%) developed ototoxicity (with a Brock grade ≥2). The probability of hearing loss increased significantly in patients carrying the null genotype for GSTT1 (P = 0.03), A/A genotype at rs1695 (P = 0.01), and C/C genotype at rs1799793 (P = 0.008). We also showed an association of the cumulative doses of carboplatin with cisplatin ototoxicity (P <0.05). To conclude, deletion of GSTT1, rs1695 and rs1799793 may constitute potential predictors of platinum-induced ototoxicity.

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.

Ototoxicity: A Challenge in Diagnosis and Treatment

Ototoxicity is the pharmacological adverse reaction affecting the inner ear or auditory nerve, characterized by cochlear or vestibular dysfunction. The panorama of drug-induced hearing loss has widened over last few decades. Although ototoxic medications play an imperative role in modern medicine, they have the capacity to cause harm and lead to significant morbidity. Evidence has shown early detection of toxicity through prospective ototoxicity monitoring allows for consideration of treatment modifications to minimize or prevent permanent hearing loss and balance impairment. Although many ototoxicity monitoring protocols exist, their practicality is questionable due to several factors. Even though the existing protocols have proven to be effective, certain lacunae in practice have been encountered due to discrepancies among recommended protocols. Implementation of these protocols is mostly held back due to the incapacitated status of the patient. The choice of early ototoxicity identification techniques is still debatable due to variables such as high degree of sensitivity, specificity and reliability, less time consumption and less labour-intensive to the patient. Hence, the diagnosis and effective treatment of ototoxicity is challenging, even today. A stringent protocol with more practicality encompassing all elements aimed at profiling the effects of ototoxicity is greatly needed. This review describes an efficient application of ototoxicity monitoring and treatment protocol as an attempt to reduce the challenges in diagnosis and management of ototoxicity.

Effect of Remote Ischemic Preconditioning on Systemic Toxicity and Ototoxicity Induced by Cisplatin in Rats: Role of TNF-α and Nitric Oxide

BACKGROUND/AIMS

Cisplatin is a chemotherapeutic agent. The use of remote ischemic preconditioning (RIPC) was proposed after the observation that ischemic preconditioning of a cardiac vascular area could protect another completely distinctly.

METHODS

This is an experimental study. Male Wistar rats were anesthetized, and they underwent a hearing evaluation via measurement of the brainstem auditory evoked potential (BSAEP). Then, cisplatin was administered intraperitoneally (IP) at a dose of 8 mg/kg/day for 4 consecutive days to group 1, whereas saline solution was administered IP to group 2. In groups 3 and 4, ischemia of the right hind paw was performed for 10 min, followed by reperfusion for 30 min, after which cisplatin or saline was administered IP to group 3 or group 4, respectively. Afterwards, all animals were evaluated via the BSAEP. The right cochlea was dissected for immunohistochemistry.

RESULTS

RIPC lowered the increase in BSAEP of the animals treated with cisplatin (p = 0.0146). Weight loss decreased in the animals subjected to RIPC (p < 0.005). In group 3, RIPC reversed immunostaining for tumor necrosis factor-α and inducible nitric oxide synthase in the stria vascularis injured by cisplatin (p < 0.05).

CONCLUSION

RIPC protects against systemic toxicity and ototoxicity induced by cisplatin in rats.

Medicações ototóxicas utilizadas no tratamento oncológico pediátrico: uma revisão sistemática

RESUMO Objetivo Fazer um levantamento dos medicamentos ototóxicos utilizados no tratamento do câncer pediátrico, apontar os danos das drogas para o sistema auditivo e os métodos utilizados na identificação destes danos nessa população. Estratégia de pesquisa: Foram utilizados periódicos nacionais e internacionais pertinentes ao assunto, acessados eletronicamente em bases de dados da Biblioteca Virtual em Saúde - MS, PubMed, Biblioteca Digital Brasileira de Teses e Dissertações, que envolvessem a população pediátrica com histórico de tratamento oncológico, publicados entre 2007 e 2016, e no Banco de Teses e Dissertações da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior. Critérios de seleção Foram selecionados estudos que contemplassem os seguintes critérios: estudos observacionais nas línguas portuguesa, inglesa ou espanhola e resumos disponíveis que informassem o método de avaliação do dano auditivo. Resultados A amostra final resultou em 12 artigos. Destes, a audiometria tonal limiar foi o método de avaliação auditiva mais utilizado, estando presente em 10 (84,61%) dos estudos, seguido das emissões otoacústicas (46,15%). Todos os estudos foram desenvolvidos com pacientes que fizeram uso de cisplatina ou derivados da platina e, quanto ao dano auditivo, apenas 1 dos estudos incluídos não relatou presença de alteração na população estudada. Conclusão Os derivados da platina expressam papel importante no tratamento do câncer em diversos níveis e são os agentes ototóxicos mais citados em pesquisas. A cóclea é o local mais afetado, mais especificamente as células ciliadas externas. Os métodos de investigação da alteração auditiva mais utilizados são a audiometria tonal limiar e as emissões otoacústicas.

COAST (Cisplatin ototoxicity attenuated by aspirin trial): A phase II double-blind, randomised controlled trial to establish if aspirin reduces cisplatin induced hearing-loss

BACKGROUND

Cisplatin is one of the most ototoxic chemotherapy drugs, resulting in a permanent and irreversible hearing loss in up to 50% of patients. Cisplatin and gentamicin are thought to damage hearing through a common mechanism, involving reactive oxygen species in the inner ear. Aspirin has been shown to minimise gentamicin-induced ototoxicity. We, therefore, tested the hypothesis that aspirin could also reduce ototoxicity from cisplatin-based chemotherapy.

METHODS

A total of 94 patients receiving cisplatin-based chemotherapy for multiple cancer types were recruited into a phase II, double-blind, placebo-controlled trial and randomised in a ratio of 1:1 to receive aspirin 975 mg tid and omeprazole 20 mg od, or matched placebos from the day before, to 2 days after, their cisplatin dose(s), for each treatment cycle. Patients underwent pure tone audiometry before and at 7 and 90 days after their final cisplatin dose. The primary end-point was combined hearing loss (cHL), the summed hearing loss at 6 kHz and 8 kHz, in both ears.

RESULTS

Although aspirin was well tolerated, it did not protect hearing in patients receiving cisplatin (p-value = 0.233, 20% one-sided level of significance). In the aspirin arm, patients demonstrated mean cHL of 49 dB (standard deviation [SD] 61.41) following cisplatin compared with placebo patients who demonstrated mean cHL of 36 dB (SD 50.85). Women had greater average hearing loss than men, and patients treated for head and neck malignancy experienced the greatest cHL.

CONCLUSIONS

Aspirin did not protect from cisplatin-related ototoxicity. Cisplatin and gentamicin may therefore have distinct ototoxic mechanisms, or cisplatin-induced ototoxicity may be refractory to the aspirin regimen used here.

Clinical Practice Recommendations for the Management and Prevention of Cisplatin-Induced Hearing Loss Using Pharmacogenetic Markers

Currently no pharmacogenomics-based criteria exist to guide clinicians in identifying individuals who are at risk of hearing loss from cisplatin-based chemotherapy. This review summarizes findings from pharmacogenomic studies that report genetic polymorphisms associated with cisplatin-induced hearing loss and aims to (1) provide up-to-date information on new developments in the field, (2) provide recommendations for the use of pharmacogenetic testing in the prevention, assessment, and management of cisplatin-induced hearing loss in children and adults, and (3) identify knowledge gaps to direct and prioritize future research. These practice recommendations for pharmacogenetic testing in the context of cisplatin-induced hearing loss reflect a review and evaluation of recent literature, and are designed to assist clinicians in providing optimal clinical care for patients receiving cisplatin-based chemotherapy.

Cisplatin is retained in the cochlea indefinitely following chemotherapy

Cisplatin chemotherapy causes permanent hearing loss in 40–80% of treated patients. It is unclear whether the cochlea has unique sensitivity to cisplatin or is exposed to higher levels of the drug. Here we use inductively coupled plasma mass spectrometry (ICP-MS) to examine cisplatin pharmacokinetics in the cochleae of mice and humans. In most organs cisplatin is detected within one hour after injection, and is eliminated over the following days to weeks. In contrast, the cochlea retains cisplatin for months to years after treatment in both mice and humans. Using laser ablation coupled to ICP-MS, we map cisplatin distribution within the human cochlea. Cisplatin accumulation is consistently high in the stria vascularis, the region of the cochlea that maintains the ionic composition of endolymph. Our results demonstrate long-term retention of cisplatin in the human cochlea, and they point to the stria vascularis as an important therapeutic target for preventing cisplatin ototoxicity.

Permanent hearing loss occurs in many cancer patients treated with cisplatin. In this study, the authors examine cisplatin pharmacokinetics in the cochleae of mice and humans showing that cisplatin is retained for months to years after treatment.

TPMT, COMT and ACYP2 genetic variants in paediatric cancer patients with cisplatin-induced ototoxicity

OBJECTIVES

Cisplatin ototoxicity affects 42-88% of treated children. Catechol-O-methyltransferase (COMT), thiopurine methyltransferase (TPMT) and AYCP2 genetic variants have been associated with ototoxicity, but the findings have been contradictory. The aims of the study were as follows: (a) to investigate these associations in a carefully phenotyped cohort of UK children and (b) to perform a systematic review and meta-analysis.

METHODS

We recruited 149 children from seven UK centres using a retrospective cohort study design. All participants were clinically phenotyped carefully. Genotyping was performed for one ACYP2 (rs1872328), three TPMT (rs12201199, rs1142345 and rs1800460) and two COMT (rs4646316 and rs9332377) variants.

RESULTS

For CTCAE grading, hearing loss was present in 91/120 (75.8%; worst ear) and 79/120 (65.8%; better ear). Using Chang grading, hearing loss was diagnosed in 85/119 (71.4%; worst ear) versus 75/119 (63.0%; better ear). No TPMT or COMT single-nucleotide polymorphisms (SNPs) were associated with ototoxicity. ACYP2 SNP rs1872328 was associated with ototoxicity (P=0.027; worst ear). Meta-analysis of our data with that reported in previous studies showed the pooled odds ratio (OR) to be statistically significant for both the COMT SNP rs4646316 (OR: 1.50; 95% confidence interval: 1.15-1.95) and the ACYP2 SNP rs1872328 (OR: 5.91; 95% confidence interval: 1.51-23.16).

CONCLUSION

We showed an association between the ACYP2 polymorphism and cisplatin-induced ototoxicity, but not with the TPMT and COMT. A meta-analysis was statistically significant for both the COMT rs4646316 and the ACYP2 rs1872328 SNPs. Grading the hearing of children with asymmetric hearing loss requires additional clarification.

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.

Analysis of Cisplatin-Induced Ototoxicity Risk Factors in Iranian Patients with Solid Tumors: a Cohort, Prospective and Single Institute Study

Background: Cisplatin has been associated with irreversible hearing damage. Up to now, there is no therapeutic intervention showing benefit in preventing Cisplatin-induced ototoxicity. The aim of this study was to determine risk factors contributing to hearing impairment after cisplatin administration in Iranian patients. Methods: Hearing thresholds of 124 patients before and after cisplatin administration were assessed with reference to pure-tone audiometry averages at several frequencies from 2006 to 2010. Mean values were calculated at each tested frequency in each ear at baseline and subsequent follow-up audiometry. Hearing impairment was assessed with the Münster score. Results: The mean age at diagnosis and the median cumulative Cisplatin dose were 47.3 years and 453.8 milligrams, respectively. Bilateral hearing loss, mostly of grade 1, and tinnitus were detected in 26% and 3.2% of patients. Logistic regression analysis showed that a high cumulative dose of cisplatin was the most important risk factor for developing hearing damage (P=0.034). The most significant changes in the status of the auditory system and the most severe threshold shift from base line (35 dB) were observed at a frequency of 8 kHz. Also, patients who received higher individual doses of Cisplatin showed significantly more tinnitus (P=0.002). Conclusions: The results are testament to benefits of routine audiometric monitoring program during cisplatin-based chemotherapy. Further research should be performed to understand other risk factors, such as genetic predictors of Cisplatin-induced ototoxicity.

Long-term ototoxicity in women after cisplatin treatment for ovarian germ cell cancer

OBJECTIVE

Evaluate long-term cisplatin-induced ototoxicity in women treated for malignant ovarian germ cell tumors (MOGCT).

METHODS

Seventy-four women treated for MOGCT in Norway (1980-2009) were analyzed: 41 had received cisplatin-based chemotherapy (CBCT) ("Cases") and 33 had no CBCT ("Controls"). Median follow-up was 15years. Hearing was assessed by pure tone audiometry and by the SCIN questionnaire. Air conduction thresholds were reported as absolute hearing thresholds and age-adjusted thresholds. Absolute and age-adjusted hearing loss were defined as thresholds of >20dB at any frequency. Tinnitus was evaluated using the Tinnitus Handicap Inventory. Serum Platinum Concentration (SPC) was determined.

RESULTS

Absolute hearing loss was identified in 21 Cases (51%) and 24 Controls (73%). After adjusting for age, only 9 Cases (22%) and 5 Controls (15%) remained. Age-adjusted hearing thresholds at 4, 6 and 8kHz were slightly but significantly higher in Cases compared to Controls. Subjective hearing loss was reported by 27% of Cases and 21% of Controls, who were significantly older. Elevated SPC values were detected up to 20years after CBCT, but SPC did not correlate significantly with age-adjusted hearing loss. The rate of tinnitus was similar in Cases and Controls.

CONCLUSION

Long-term MOGCT survivors treated with CBCT have small but significant reductions in age-adjusted hearing thresholds at 4, 6 and 8kHz versus Controls. Approximately one in four women experienced subjective hearing loss. To avoid overestimation of clinically relevant cisplatin-induced ototoxicity, absolute hearing thresholds should be age-adjusted and compared to an age-matched control group.

Long-term auditory complications after childhood cancer: A report from the Swiss Childhood Cancer Survivor Study

BACKGROUND

Auditory complications are an adverse event of childhood cancer treatment, especially common in children treated with platinum chemotherapy or cranial radiation. Variation between diagnostic childhood cancer groups has rarely been studied, and we do not know if the burden of auditory complications has changed over the last decades.

PROCEDURE

Within the Swiss Childhood Cancer Survivor Study, we sent a questionnaire to all survivors who were diagnosed at age 16 years or less between 1976 and 2005. We compared prevalence of self-reported hearing loss and tinnitus between all diagnostic childhood cancer groups and siblings, used multivariable logistic regression to analyze the effect of treatment-related factors on hearing loss, and compared the cumulative incidence of hearing loss between different periods of cancer diagnosis.

RESULTS

Prevalence of self-reported hearing loss was higher in survivors (10%) than in siblings (3%, P < 0.001), and highest in survivors of central nervous system tumors (25%). Significant risk factors were treatment with platinum compounds (carboplatin: odds ratio [OR] 2.4; cisplatin: OR 9.4), cranial radiation (>29 Gy: OR >1.7), or brain surgery (OR 2.2). Children diagnosed in 1986-1995, when platinum compounds came into widespread use, had a significantly higher cumulative incidence of hearing loss than those diagnosed in 1976-1985. In the most recent period, 1996-2005, the risk decreased again, both for patients treated with platinum compounds and with cranial radiation.

CONCLUSIONS

Our data show that the burden of hearing loss has stabilized in recently treated survivors, suggesting that survivors have benefited from new treatment regimens that use less ototoxic radiation and more carefully dosed platinum compounds.

Cisplatin-Associated Ototoxicity: A Review for the Health Professional

Cisplatin is an effective drug used in the treatment of many cancers, yet its ototoxic potential places cancer patients, exposed to this drug, at risk of hearing loss, thus negatively impacting further on a patient's quality of life. It is paramount for health care practitioners managing such patients to be aware of cisplatin's ototoxic properties and the clinical signs to identify patients at risk of developing hearing loss. English peer-reviewed articles from January 1975 to July 2015 were assessed from PubMed, Science Direct, and Ebscohost. Seventy-nine articles and two books were identified for this review, using MeSH terms and keywords such as "ototoxicity", "cisplatin", "hearing loss", and "ototoxicity monitoring". This review provides an up-to-date overview of cisplatin-associated ototoxicity, namely, its clinical features, incidence rates, and molecular and cellular mechanisms and risk factors, to health care practitioners managing the patient with cancer, and highlights the need for a team-based approach to complement an audiological monitoring programme to mitigate any further loss in the quality of life of affected patients, as there is currently no otoprotective agent recommended routinely for the prevention of cisplatin-associated ototoxicity. It also sets the platform for effective dialogue towards policy formulation and strengthening of health systems in developing countries.

Ototoxicity management: An investigation into doctors' knowledge and practices, and the roles of audiologists in a tertiary hospital

BACKGROUND

A significant number of medications that are prescribed by doctors to treat cancers, tuberculosis and infections are ototoxic. Disclosure of ototoxic risks is ethical practice as patients have the right to be properly informed about and involved in decisions about their health care. Often, doctors fail to disclose such information.

AIM

This research investigated whether a group of doctors working in a South African academic hospital inform their patients about the ototoxic risks associated with specific medications, and if not, explore the reasons for it. It was determined what the participants' knowledge levels of ototoxicity were as knowledge is seen as a precursor to disclosing information to their patients. A further aim of the research was to determine whether audiologists should expand their role by sharing information with patients and other professionals in the management of ototoxicity and in the hospital.

METHOD

There were 90 participants included in the study through convenience sampling, which represented interns, medical officers, registrars and consultants in the neonatal intensive care unit, intensive care unit, ear-nose-throat, and internal and family medicine departments. The research made use of a descriptive survey design that collected mainly quantitative data and a limited amount of qualitative data through questionnaires. The data were descriptively analysed, and the qualitative data were listed and quantified.

RESULTS

The research firstly determined the participants' knowledge and understanding of ototoxicity, and it was found that there was room for improvement. With reference to the current practices of doctors in the prescription of ototoxic medicines, it was found that disclosure of ototoxic risks was limited, mostly because of a lack of time and insufficient knowledge. In comparing knowledge and practices between levels of employment, it was found that particular post levels performed better than others. The participants regarded the role of the audiologist as team member important, although very few referred their patients for audiological monitoring when they prescribe ototoxic medication.

CONCLUSION

A need for additional support to doctors was identified, which indicates that audiologists should expand their role to include the provision of continued professional development activities and to renew their efforts to advocate their role in the hospital so that doctors are made aware of the importance to refer their patients for ototoxic screening and monitoring.

Determinants of ototoxicity in 451 platinum-treated Dutch survivors of childhood cancer: A DCOG late-effects study

Platinum-containing chemotherapeutics are efficacious for a variety of pediatric malignancies, nevertheless these drugs can induce ototoxicity. However, ototoxicity data on large cohorts of childhood cancer survivors (CCSs) who received platinum agents, but not cranial irradiation are scarce. Therefore, we have studied the frequency and determinants of ototoxicity in a cross-sectional multicenter CCS cohort, including the role of co-medication since it has been suggested that these play a role in ototoxicity. We have collected treatment data and audiograms from the medical records of CCS treated in the seven pediatric oncology centres in The Netherlands. Ototoxicity was defined as Münster grade ≥2b (>20 dB at ≥4-8 kHz). Four-hundred-fifty-one CCS who received platinum agents, but not cranial irradiation (median age at diagnosis: 4.9 years, range: 0.01-19 years) were included. The overall frequency of ototoxicity was 42%. Ototoxicity was observed in 45% of the cisplatin-treated CCS, in 17% of the carboplatin-treated CCS and in 75% of the CCS that had received both agents. Multivariate analysis showed that younger age at diagnosis (odds ratio [OR]: 0.6, 95% confidence interval [CI]: 0.5-0.6 per 5 years increase); higher total cumulative dose cisplatin (OR: 1.2, 95% CI: 1.2-1.5 per 100 mg/m² increase); and co-treatment with furosemide (OR: 2.3, 95% CI: 1.4-3.9) were associated with ototoxicity. We conclude that treatment with (higher total cumulative dose of) cisplatin, young age and furosemide co-medication independently are associated with an increased risk of ototoxicity in CCS. Future prospective studies are necessary to confirm the additive risk of co-medication on the development of ototoxicity.

Analysis of genetic and non genetic risk factors for cisplatin ototoxicity in pediatric patients

OBJECTIVE

The aim of this study was to analyse the genetic and non genetic risk factors for cisplatin ototoxicity.

METHODS

This study was conducted on 72 children who received cisplatin based chemotherapy. Brock and Muenster classifications were used to evaluate ototoxicity seen in these children. 6 single nucleotide polymorphisms (SNP); ERCC1 rs 11615, GSTP1 rs1138272, GSTP1 rs1695, LRP2 rs 2075252, TPMT rs 12201199, COMT rs 9332377, were evaluated as genetic factors by real time PCR. Non genetic factors such as cranial irradiation, cumulative doses of cisplatin, age, gender, administration of other ototoxic drugs were analysed as well. By using Chi-square test, risk factors were matched with the ototoxicity classifications. Significant risk factors were reevaluated using logistic regression modelling.

RESULTS

According to univariate analyses, male gender, co-treatment with aminoglycosides and mutant genotype of GSTP1 rs1695 were significantly related with cisplatin ototoxicity. Logistic regression modelling analyses also showed that male gender, co-treatment with aminoglycosides were found to be significantly related with cisplatin ototoxicity. Mutant genotype of GSTP1 rs1695 was not found to be significant, but close to the level of statistical significance.

CONCLUSION

Male gender, co-treatment with aminoglycosides are significant risk factors for cisplatin ototoxicity in pediatric patients. Mutant genotype of GSTP1 rs1695 seems to be a genetic risk factor in univariate analyses, although not confirmed by multivariate analyses. Therefore, GSTP1 rs1695 SNP needs to be studied in larger series.

Audiological profile of patients treated for childhood cancer

OBJECTIVE

To characterize the hearing loss after cancer treatment, according to the type of treatment, with identification of predictive factors.

METHODS

Two hundred patients who had cancer in childhood were prospectively evaluated. The mean age at diagnosis was 6 years, and at the audiometric assessment, 21 years. The treatment of the participants included chemotherapy without using platinum derivatives or head and neck radiotherapy in 51 patients; chemotherapy using cisplatin without radiotherapy in 64 patients; head and neck radiotherapy without cisplatin in 75 patients; and a combined treatment of head and neck radiotherapy and chemotherapy with cisplatin in ten patients. Patients underwent audiological assessment, including pure tone audiometry, speech audiometry, and immittancemetry.

RESULTS

The treatment involving chemotherapy with cisplatin caused 41.9% and 47.3% hearing loss in the right and left ear, respectively, with a 11.7-fold higher risk of hearing loss in the right ear and 17.6-fold higher in the left ear versus patients not treated with cisplatin (p<0.001 and p<0.001, respectively). Children whose cancer diagnosis occurred after the age of 6 have shown an increased risk of hearing loss vs. children whose diagnosis occurred under 6 years of age (p=0.02).

CONCLUSION

The auditory feature found after the cancer treatment was a symmetrical bilateral sensorineural hearing loss. Chemotherapy with cisplatin proved to be a risk factor, while head and neck radiotherapy was not critical for the occurrence of hearing loss.

Platinum-induced hearing loss after treatment for childhood cancer

BACKGROUND

Platinum-based therapy, including cisplatin, carboplatin, oxaliplatin or a combination of these, is used to treat a variety of paediatric malignancies. Unfortunately, one of the most important adverse effects is the occurrence of hearing loss or ototoxicity. There is a wide variation in the reported prevalence of platinum-induced ototoxicity and the associated risk factors. More insight into the prevalence of and risk factors for platinum-induced hearing loss is essential in order to develop less ototoxic treatment protocols for the future treatment of children with cancer and to develop adequate follow-up protocols for childhood cancer survivors treated with platinum-based therapy.

OBJECTIVES

To evaluate the existing evidence on the association between childhood cancer treatment including platinum analogues and the occurrence of hearing loss.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 8), MEDLINE (PubMed) (1945 to 23 September 2015) and EMBASE (Ovid) (1980 to 23 September 2015). In addition, we searched reference lists of relevant articles and the conference proceedings of the International Society for Paediatric Oncology (2008 to 2014), the American Society of Pediatric Hematology/Oncology (2008 to 2015) and the International Conference on Long-Term Complications of Treatment of Children and Adolescents for Cancer (2010 to 2015). Experts in the field provided information on additional studies.

SELECTION CRITERIA

All study designs, except case reports, case series (i.e. a description of non-consecutive participants) and studies including fewer than 100 participants treated with platinum-based therapy who had an ototoxicity assessment, examining the association between childhood cancer treatment including platinum analogues and the occurrence of hearing loss.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection. One review author performed data extraction and risk of bias assessment, which was checked by another review author.

MAIN RESULTS

We identified 13 eligible cohort studies including 2837 participants with a hearing test after treatment with a platinum analogue for different types of childhood cancers. All studies had methodological limitations, with regard to both internal (risk of bias) and external validity. Participants were treated with cisplatin, carboplatin or both, in varying doses. The reported prevalence of hearing loss varied considerably between 0% and 90.1%; none of the studies provided data on tinnitus. Three studies reported a prevalence of 0%, but none of these studies provided a definition for hearing loss and there might be substantial or even complete overlap in included participants between these three studies. When only studies that did provide a definition for hearing loss were included, the prevalence of hearing loss still varied widely between 1.7% and 90.1%. All studies were very heterogeneous with regard to, for example, definitions of hearing loss, used diagnostic tests, participant characteristics, (prior) anti-tumour treatment, other ototoxic drugs and length of follow-up. Therefore, pooling of results was not possible.Only two studies included a control group of people who had not received platinum treatment. In one study, the prevalence of hearing loss was 67.1% (95% confidence interval (CI) 59.3% to 74.1%) in platinum-treated participants, while in the control participants it was 7.4% (95% CI 6.2% to 8.8%). However, hearing loss was detected by screening in survivors treated with platinum analogues and by clinical presentation in control participants. It is uncertain what the effect of this difference in follow-up/diagnostic testing was. In the other study, the prevalence of hearing loss was 20.1% (95% CI 17.4% to 23.2%) in platinum-treated participants and 0.4% (95% CI 0.12% to 1.6%) in control participants. As neither study was a randomized controlled trial or controlled clinical trial, the calculation of a risk ratio was not feasible as it is very likely that both groups differed more than only the platinum treatment.Only two studies evaluated possible risk factors using multivariable analysis. One study identified a significantly higher risk of hearing loss in people treated with cisplatin 400 mg/m(2) plus carboplatin 1700 mg/m(2) as compared to treatment with cisplatin 400 mg/m(2) or less, irrespective of the definition of hearing loss. They also identified a significantly higher risk of hearing loss in people treated with non-anthracycline aminoglycosides antibiotics (using a surrogate marker) as compared to people not treated with them, for three out of four definitions of hearing loss. The other study reported that age at treatment (odds ratio less than 1 for each single-unit increase) and single maximum cisplatin dose (odds ratio greater than 1 for each single-unit increase) were significant predictors for hearing loss, while gender was not.

AUTHORS' CONCLUSIONS

This systematic review shows that children treated with platinum analogues are at risk for developing hearing loss, but the exact prevalence and risk factors remain unclear. There were no data available for tinnitus. Based on the currently available evidence we can only advise that children treated with platinum analogues are screened for ototoxicity in order to make it possible to diagnose hearing loss early and to take appropriate measures. However, we are unable to give recommendations for specific follow-up protocols including frequency of testing. Counselling regarding the prevention of noise pollution can be considered, such as the use of noise-limiting equipment, avoiding careers with excess noise and ototoxic medication. Before definitive conclusions on the prevalence and associated risk factors of platinum-induced ototoxicity can be made, more high-quality research is needed. Accurate and transparent reporting of findings will make it possible for readers to appraise the results of these studies critically.

Promoter region variation in NFE2L2 influences susceptibility to ototoxicity in patients exposed to high cumulative doses of cisplatin

Ototoxicity is a disabling reaction to cisplatin chemotherapy. Much of the inter-individual variability in the development of hearing impairment among cisplatin-receiving patients has not been fully accounted for. In particular, little is known about the pharmacogenomics of cisplatin-induced ototoxicity. This study sought to investigate the role of variation in five candidate genes in a cohort of South African cancer patients. Five variants within the candidate genes were genotyped in 214 patients, of which SLC22A2 rs316019 and NFE2L2 rs6721961 associated with reduced rates of ototoxicity. In the patients who were exposed to cumulative cisplatin doses ⩾200 mg m^-2 (n=113), the variant rs6721961 associated with ototoxicity according to three different grading scales of hearing loss (ASHA, P=0.005; Chang, P=0.028; CTCAE, P=0.004). The NFE2L2 promotor variant rs6721961 may therefore be protective against hearing loss in cisplatin-receiving cancer patients.

The role of pharmacogenetics in the treatment of osteosarcoma

In osteosarcoma, large variation is observed in the efficacy and toxicity of chemotherapeutic drugs among similarly treated patients. Treatment optimization using predictive factors or algorithms is of importance, because there has been a lack of improvement of treatment outcome and survival for decades. The outcome of cancer treatment is influenced by the genome, thus studying genetic variants involved in the efficacy and toxicity of the chemotherapeutic drugs used in the treatment of osteosarcoma could be an opportunity to optimize current treatments and improve our understanding of the individual's drug response in osteosarcoma patients. This review discusses the current insights in the pharmacogenetics of the treatment response of osteosarcoma patients regarding efficacy and toxicity, and implications for future research and treatment.

Audiological Monitoring in Children Treated with Platinum Chemotherapy

Platinum compounds constitute the standard treatment for solid tumors in pediatric oncology. The purpose of this study is to assess the impact of platinum compounds in the development of ototoxicity in children following chemotherapy. This study included 160 patients treated with cisplatin and carboplatin for malignant solid diseases from 2007 to 2014. Their audiograms were classified according to the Boston SIOP ototoxicity scale. Twenty-five percent of the children treated with platinum compounds developed ototoxicity. The incidence of ototoxicity was correlated with the type of platinum derivative (i.e. cisplatin vs. carboplatin), coadministration of both drugs and concomitant cranial radiotherapy, but not with sex and age. Cumulative dose was correlated only with the cisplatin administration. Nine patients (8.6%) showed further progression of hearing impairment after the end of chemotherapy. The low rate of ototoxicity suggests the pivotal role of auditory monitoring in children treated with platinum compounds in order to be able to identify hearing loss at an early stage and to provide, jointly with pediatric oncologists, strategies to reduce further progression of cochlear toxicity.

Replication of a genetic variant in ACYP2 associated with cisplatin-induced hearing loss in patients with osteosarcoma

OBJECTIVE

Irreversible hearing loss is a frequent side effect of the chemotherapeutic agent cisplatin and shows considerable interpatient variability. The variant rs1872328 in the ACYP2 gene was recently identified as a risk factor for the development of cisplatin-induced ototoxicity in children with brain tumors. We aimed to replicate this finding in patients with osteosarcoma.

METHODS

An independent cohort of 156 patients was genotyped for the rs1872328 variant and evaluated for the presence of cisplatin-induced ototoxicity.

RESULTS

A significant association was observed between carriership of the A allele and cisplatin-induced ototoxicity after the end of treatment (P=0.027).

CONCLUSION

This is the first study replicating the association of ACYP2 variant rs1872328 with cisplatin-induced ototoxicity in patients with osteosarcoma who did not receive potentially ototoxic cranial irradiation. Hence, the ACYP2 variant should be considered a predictive pharmacogenetic marker for hearing loss, which may be used to guide therapies for patients treated with cisplatin.

Long-term audiologic follow-up of carboplatin-treated children with retinoblastoma

BACKGROUND

Children treated for retinoblastoma with carboplatin have an increased risk for ototoxicity. Impaired hearing may have major consequences for these children, because they often suffer from reduced vision. Previous studies have shown limited information on the incidence and severity of carboplatin-induced ototoxicity and the used audiologic methods. The frequency of audiological testing is often limited and the audiologic follow-up time is relatively short.

OBJECTIVE

The aim of this study was to determine the long-term effects of carboplatin ototoxicity in children with retinoblastoma.

MATERIALS AND METHODS

In this retrospective non-randomized single center cohort study, we reviewed audiologic results of 25 patients. Experienced audiologists analyzed the pure-tone audiograms.

RESULTS

All patients had normal hearing prior to therapy and had a mean age of 11 months at first carboplatin administration. The mean audiologic follow-up was 12.0 years with a median of 11.6 (IQR 4.8) years. Three patients were excluded: two passed away and one could not participate in the audiologic tests. One of the 22 included patients developed sustained low-grade bilateral high-frequency hearing loss between 2 and 7 years after the last carboplatin dose. In one patient it was not possible to make a reliable conclusion due to a conductive hearing loss component. Twenty patients had normal hearing.

CONCLUSIONS

We observed no clear effect between carboplatin administration in young children and clinical significant ototoxicity in the long term. One child showed low-grade bilateral high-frequency hearing loss.

Human OCT2 variant c.808G>T confers protection effect against cisplatin-induced ototoxicity

AIM

Assuming that genetic variants of the SLC22A2 and SLC31A1 transporter affect patients' susceptibility to cisplatin-induced ototoxicity, we compared the distribution of 11 SLC22A2 variants and the SLC31A1 variant rs10981694 between patients with and without cisplatin-induced ototoxicity.

PATIENTS & METHODS

Genotyping was performed in 64 pediatric patients and significant findings were re-evaluated in 66 adults.

RESULTS

The SLC22A2 polymorphism rs316019 (c.808G>T; Ser270Ala) was significantly associated with protection from cisplatin-induced ototoxicity in the pediatric (p = 0.022) and the adult cohort (p = 0.048; both: Fisher's exact test). This result was confirmed by multiple logistic regression analysis accounting for age which was identified as a relevant factor for ototoxicity as well (rs316019: OR [G/T vs G/G] = 0.12, p = 0.009; age: OR [per year]: 0.84, p = 0.02).

CONCLUSION

These results identified rs316019 as potential pharmacogenomic marker for cisplatin-induced ototoxicity and point to a critical role of SLC22A2 for cisplatin transport in humans and its contribution to the organ specific side effects of this drug. Original submitted 17 September 2014; Revision submitted 19 December 2014.

Cochlear Implantation for Profound Hearing Loss After Multimodal Treatment for Neuroblastoma in Children

Objectives

Neuroblastoma (NBL) predominantly affects children under 5 years of age. Through multimodal therapy, including chemotherapy, radiotherapy, surgery, and peripheral blood stem cell transplantation, the survival rate in patients with NBL have improved while treatment-related complications have also increased. Treatment-related ototoxicity, mainly from cisplatin, can result in profound hearing loss requiring cochlear implantation (CI). We analyzed the effectiveness and hearing preservation of CI recipients who had treated with multimodal therapy due to NBL.

Methods

Patients who received multimodal therapy for NBL and subsequent CIs were enrolled. A detailed review of the perioperative hearing test, speech evaluation, and posttreatment complications was conducted. Speech performance was analyzed using the category of auditory performance (CAP) score and the postoperative hearing preservation of low frequencies was also compared. Patients who were candidates for electro-acoustic stimulation (EAS) used an EAS electrode for low frequency hearing preservation.

Results

Three patients were identified and all patients showed improvement of speech performance after CI. The average of CAP score improved from 4.3 preoperatively to 5.8 at 1 year postoperatively. Two patients who were fitted with the Flex electrode showed complete hearing preservation and the preserved hearing was maintained over 1 year. The one remaining patient was given the standard CI-512 electrode and showed partial hearing preservation.

Conclusion

Patients with profound hearing loss resulting from NBL multimodal therapy can be good candidates for CI, especially for EAS. A soft surgical technique as well as a specifically designed electrode should be applied to this specific population during the CI operation in order to preserve residual hearing and achieve better outcomes.

SOD2 genetic variant associated with treatment-related ototoxicity in cisplatin-treated pediatric medulloblastoma

Manganese superoxide dismutase (MnSOD), encoded by the SOD2 gene, is involved in the detoxification of superoxide anion. Superoxide is likely a source of oxidative stress in the cochlea following treatment with platinum agents and radiation. Therefore, we examined SOD2 variants in association with ototoxicity among cisplatin-treated childhood medulloblastoma patients. Blood samples were obtained from 71 eligible patients treated for pediatric medulloblastoma at Texas Children’s Cancer Center (1987–2010). Ototoxicity was defined as requiring the use of a hearing aid sometime after the initiation of therapy. DNA was genotyped on the Illumina HumanOmni-1 Quad BeadChip. A linkage disequilibrium (LD)-based single-nucleotide polymorphism (SNP) selection strategy was used to identify a minimal set of informative variants. Associations between SNPs and ototoxicity were assessed using logistic regression. Of the 71 eligible patients, 26 (37%) suffered from cisplatin-related ototoxicity. Study participants were primarily male (73%) and non-Hispanic white (42%). Five SOD2 variants (rs7855, rs5746151, rs5746136, rs2758331, and rs4880) identified by the LD-based selection strategy were genotyped. After correcting for multiple comparisons, the C-allele of the rs4880 variant was significantly associated with ototoxicity (odds ratio = 3.06, 95% confidence interval: 1.30–7.20) in adjusted models. The rs4880 T > C substitution results in a Val > Ala amino acid change at position 16 of the MnSOD mitochondrial targeting sequence. The Ala variant, which has been associated with increased MnSOD activity, was associated with hearing damage in this study. Platinum-based therapies increase the expression of MnSOD, which may result in an abundance of hydrogen peroxide, a reactive oxygen species. Therefore, oxidative stress may be an important mechanism in therapy-related cochlear damage.

Cisplatin-Induced Ototoxicity: Effects, Mechanisms and Protection Strategies

Cisplatin is a highly effective chemotherapeutic agent that is widely used to treat solid organ malignancies. However, serious side effects have been associated with its use, such as bilateral, progressive, irreversible, dose-dependent neurosensory hearing loss. Current evidence indicates that cisplatin triggers the production of reactive oxygen species in target tissues in the inner ear. A variety of agents that protect against cisplatin-induced ototoxicity have been successfully tested in cell culture and animal models. However, many of them interfere with the therapeutic effect of cisplatin, and therefore are not suitable for systemic administration in clinical practice. Consequently, local administration strategies, namely intratympanic administration, have been developed to achieve otoprotection, without reducing the antitumoral effect of cisplatin. While a considerable amount of pre-clinical information is available, clinical data on treatments to prevent cisplatin ototoxicity are only just beginning to appear. This review summarizes clinical and experimental studies of cisplatin ototoxicity, and focuses on understanding its toxicity mechanisms, clinical repercussions and prevention strategies.

Genome-wide Association Study on Platinum-induced Hepatotoxicity in Non-Small Cell Lung Cancer Patients

Platinum-based chemotherapy has been shown to improve the survival of advanced non-small cell lung cancer (NSCLC) patients; the platinum-induced toxicity severely impedes the success of chemotherapy. Genetic variations, such as single nucleotide polymorphisms (SNPs), may contribute to patients’ responses to the platinum-based chemotherapy. To identify SNPs that modify the risk of hepatotoxicity in NSCLC patients receiving platinum-based chemotherapy, we performed a genome-wide association scan in 334 subjects followed by a replication study among 375 subjects. Consistent associations with platinum-induced hepatotoxicity risk was identified for SNP rs2838566 located at 21q22.3, as the minor A allele could significantly increase the risk of liver injury (OR = 3.78, 95%CI = 1.99–7.19, P = 4.90 × 10⁻⁵ for GWAS scan, OR = 1.89, 95%CI = 1.03–3.46, P = 0.039 for replication, and OR = 2.56, 95%CI = 1.65–3.95, P = 2.55 × 10⁻⁵ for pooled population). These results suggested that genetic variants at 21q22.3 may contribute to the susceptibility of platinum-induced hepatotoxicity in NSCLC patients.

An integrated view of cisplatin-induced nephrotoxicity and ototoxicity

Cisplatin is one of the most widely-used drugs to treat cancers. However, its nephrotoxic and ototoxic side-effects remain major clinical limitations. Recent studies have improved our understanding of the molecular mechanisms of cisplatin-induced nephrotoxicity and ototoxicity. While cisplatin binding to DNA is the major cytotoxic mechanism in proliferating (cancer) cells, nephrotoxicity and ototoxicity appear to result from toxic levels of reactive oxygen species and protein dysregulation within various cellular compartments. In this review, we discuss molecular mechanisms of cisplatin-induced nephrotoxicity and ototoxicity. We also discuss potential clinical strategies to prevent nephrotoxicity and ototoxicity and their current limitations.

N-acetylcysteine chemoprotection without decreased cisplatin antitumor efficacy in pediatric tumor models

Decreasing oxidative damage with the antioxidant agent N-acetylcysteine (NAC) can block the side effects of chemotherapy, but may diminish anti-tumor efficacy. We tested the potential for interactions of high dose NAC against a minimally effective cisplatin chemotherapy regimen in rat models of human pediatric cancers. Athymic rats received subcutaneous implantation of human SK-N-AS neuroblastoma cells or intra-cerebellar implantation of human D283-MED medulloblastoma cells. Rats were untreated or treated with cisplatin (3 or 4 mg/kg IV) with or without NAC (1,000 mg/kg IV) 30 min before or 4 h after cisplatin treatment. Blood urea nitrogen (BUN) and tumor volumes were measured. Cisplatin decreased the growth of SK-N-AS neuroblastoma subcutaneous tumors from 17.7 ± 4.9 to 6.4 ± 2.5 fold over baseline 2 weeks after treatment (P < 0.001). Pretreatment with NAC decreased cisplatin efficacy, while 4 h delayed NAC did not significantly affect cisplatin anti-tumor effects (relative tumor volume 6.8 ± 2.0 fold baseline, P < 0.001). In D283-MED medulloblastoma brain tumors, cisplatin decreased final tumor volume to 3.9 ± 2.3 mm(3) compared to untreated tumor volume of 45.9 ± 38.7 (P = 0.008). Delayed NAC did not significantly alter cisplatin efficacy (tumor volume 6.8 ± 8.1 mm(3), P = 0.014 versus control). Cisplatin was minimally nephrotoxic in these models. NAC decreased cisplatin-induced elevations in BUN (P < 0.02). NAC chemoprotection did not alter cisplatin therapy, if delayed until 4 h after chemotherapy. These data support a Phase I/II clinical trial of delayed NAC to reduce ototoxicity in children with localized pediatric cancers.

Influence of genetic variants in TPMT and COMT associated with cisplatin induced hearing loss in patients with cancer: two new cohorts and a meta-analysis reveal significant heterogeneity between cohorts

Treatment with cisplatin-containing chemotherapy regimens causes hearing loss in 40–60% of cancer patients. It has been suggested that genetic variants in the genes encoding thiopurine S-methyltransferase (TPMT) and catechol O-methyltransferase (COMT) can predict the development of cisplatin-induced ototoxicity and may explain interindividual variability in sensitivity to cisplatin-induced hearing loss. Two recently published studies however, sought to validate these findings and showed inconsistent results. The aim of this study was to evaluate the role of polymorphisms in the TPMT and COMT genes in cisplatin-induced ototoxicity. Therefore we investigated two independent cohorts of 110 Dutch and 38 Spanish patients with osteosarcoma and performed a meta-analysis including all previously published studies resulting in a total population of 664 patients with cancer. With this largest meta-analysis performed to date, we show that the influence of TPMT and COMT on the development of cisplatin-induced hearing loss may be less important than previously suggested.

Hearing loss in a pediatric patient following cisplatin chemotherapy and subsequent exposure to excessive noise

Cisplatin is a commonly-used chemotherapeutic agent that is highly-effective against a variety of pediatric cancers. Unfortunately, it may lead to ototoxicity, with serious consequences on the quality of life of survivors. Patients remain at risk of progression of ototoxicity even after completion of treatment. We report the case of a medulloblastoma survivor with previously documented normal hearing, who developed significant hearing loss and tinnitus following exposure to excessive noise at a nightclub three years after completion of treatment. We highlight the importance of long-term audiological follow up and education about the increased risk of hearing loss in this population.