Clinical and genetic risk factors for radiation-associated ototoxicity: A report from the Childhood Cancer Survivor Study and the St. Jude Lifetime Cohort

BACKGROUND

Cranial radiation therapy (CRT) is associated with ototoxicity, which manifests as hearing loss and tinnitus. The authors sought to identify clinical determinants and genetic risk factors for ototoxicity among adult survivors of pediatric cancer treated with CRT.

METHODS

Logistic regression evaluated associations of tinnitus (n = 1991) and hearing loss (n = 2198) with nongenetic risk factors and comorbidities among CRT-treated survivors in the Childhood Cancer Survivor Study. Genome-wide association studies (GWASs) of CRT-related tinnitus and hearing loss were also performed.

RESULTS

Males were more likely to report CRT-related tinnitus (9.4% vs 5.4%; P = 5.1 × 10^-4 ) and hearing loss (14.0% vs 10.7%; P = .02) than females. Survivors with tinnitus or hearing loss were more likely to experience persistent dizziness or vertigo (tinnitus: P < 2 × 10^-16 ; hearing loss: P = 6.4 × 10^-9 ), take antidepressants (tinnitus: P = .02; hearing loss: P = .01), and report poorer overall health (tinnitus: P = 1.5 × 10^-6 ; hearing loss: P = 1.7 × 10^-6 ) in comparison with controls. GWAS of CRT-related tinnitus revealed a genome-wide significant signal in chromosome 1 led by rs203248 (P = 1.5 × 10^-9 ), whereas GWAS of CRT-related hearing loss identified rs332013 (P = 5.8 × 10^-7 ) in chromosome 8 and rs67522722 (P = 7.8 × 10^-7 ) in chromosome 6 as nearly genome-wide significant. A replication analysis identified rs67522722, intronic to ATXN1, as being significantly associated with CRT-related hearing loss (P = .03) and de novo hearing loss (P = 3.6 × 10^-4 ).

CONCLUSIONS

CRT-associated ototoxicity was associated with sex, several neuro-otological symptoms, increased antidepressant use, and poorer self-reported health. GWAS of CRT-related hearing loss identified rs67522722, which was supported in an independent cohort of survivors.

LAY SUMMARY

Hearing loss and subjective tinnitus (the perception of noise or ringing in the ear) are long-term side effects of cancer treatment and are common in children treated with radiation to the brain. These toxicities can affect childhood development and potentially contribute to serious learning and behavioral difficulties. This study's data indicate that males are at greater risk for hearing loss and tinnitus than females after radiation therapy to the brain. Those who develop these toxicities are more likely to use antidepressants and report poorer overall health. Health care providers can improve the management of survivors by informing patients and/or their parents of these risks.

Clinical and genetic risk factors for radiation-associated ototoxicity: A report from the childhood cancer survivor study and the St. Jude Lifetime Cohort

10550

Background: Cranial radiation therapy (CRT) for pediatric cancer often results in ototoxicity in the form of hearing loss and tinnitus. We sought to identify clinical determinants and genetic risk factors for ototoxicity among adult survivors of pediatric cancer treated with cranial radiation. Methods: Relationships between age at last observation, sex, cumulative CRT dose and self-reported ototoxicity were evaluated for hearing loss and tinnitus among 1,991 (tinnitus) and 2,198 (hearing loss) survivors in the Childhood Cancer Survivor Study who received CRT. Logistic regression evaluated associations with non-genetic risk factors and comorbidities as well as SNP dosages in GWAS of CRT-related tinnitus (cases: 146; controls: 1,845) and hearing loss (cases: 270; controls: 1,928). Results: Males were more likely to report CRT-related tinnitus (9.4% vs. 5.4%; p = 5.81x10−4) and hearing loss (14.0% vs. 10.7%; p = 0.02) than females after adjusting for dose and age at last observation. Survivors with tinnitus or hearing loss were more likely to experience persistent dizziness or vertigo (tinnitus: p < 2.00x10−16; hearing loss: p = 6.35x10−9), take antidepressants (tinnitus: p = 0.02; hearing loss: p = 0.01) and report poorer overall health (tinnitus: p = 9.40x10−7; hearing loss: p = 1.30x10−6) compared to survivors without tinnitus or hearing loss after age-adjustment. GWAS of CRT-related tinnitus revealed a prominent signal in chromosome 1 led by rs203248 (p = 1.50x10−9), while GWAS of CRT-related hearing loss identified rs332013 (p = 5.79x10−7) in chromosome 8 and rs67522722 (p = 7.78x10−7) in chromosome 6 as approaching genome-wide significance. Replication analysis in an independent cohort of pediatric cancer survivors (SJLIFE) indicated that rs67522722, intronic to ATXN1, a gene associated with the neurodegenerative disorder spinocerebellar ataxia type 1, was significantly associated with CRT-related hearing loss (p = 0.03). Enrichment analysis and LD score regression with previous GWAS results of cisplatin-related hearing loss and tinnitus in testicular cancer survivors showed no detectable enrichment in genetic architecture with CRT-related hearing loss and tinnitus, respectively. Conclusions: Radiation-associated ototoxicity was associated with sex, several neuro-otological symptoms, increased antidepressant use and poorer self-reported health. GWAS of CRT-related hearing loss identified rs67522722 that was replicated in an independent cohort of pediatric cancer survivors.

Clinical and Genome-wide Analysis of Cisplatin-induced Tinnitus Implicates Novel Ototoxic Mechanisms

PURPOSE

Cisplatin, a commonly used chemotherapeutic, results in tinnitus, the phantom perception of sound. Our purpose was to identify the clinical and genetic determinants of tinnitus among testicular cancer survivors (TCS) following cisplatin-based chemotherapy.

EXPERIMENTAL DESIGN

TCS (n = 762) were dichotomized to cases (moderate/severe tinnitus; n = 154) and controls (none; n = 608). Logistic regression was used to evaluate associations with comorbidities and SNP dosages in genome-wide association study (GWAS) following quality control and imputation (covariates: age, noise exposure, cisplatin dose, genetic principal components). Pathway over-representation tests and functional studies in mouse auditory cells were performed.

RESULTS

Cisplatin-induced tinnitus (CisIT) significantly associated with age at diagnosis (P = 0.007) and cumulative cisplatin dose (P = 0.007). CisIT prevalence was not significantly greater in 400 mg/m²-treated TCS compared with 300 (P = 0.41), but doses >400 mg/m² (median 580, range 402-828) increased risk by 2.61-fold (P < 0.0001). CisIT cases had worse hearing at each frequency (0.25-12 kHz, P < 0.0001), and reported more vertigo (OR = 6.47; P < 0.0001) and problems hearing in a crowd (OR = 8.22; P < 0.0001) than controls. Cases reported poorer health (P < 0.0001) and greater psychotropic medication use (OR = 2.4; P = 0.003). GWAS suggested a variant near OTOS (rs7606353, P = 2 × 10^-6) and OTOS eQTLs were significantly enriched independently of that SNP (P = 0.018). OTOS overexpression in HEI-OC1, a mouse auditory cell line, resulted in resistance to cisplatin-induced cytotoxicity. Pathway analysis implicated potassium ion transport (q = 0.007).

CONCLUSIONS

CisIT associated with several neuro-otological symptoms, increased use of psychotropic medication, and poorer health. OTOS, expressed in the cochlear lateral wall, was implicated as protective. Future studies should investigate otoprotective targets in supporting cochlear cells.

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.

Adverse health outcomes in relationship to hypogonadism (HG) after platinum-based chemotherapy: A multicenter study of North American testicular cancer survivors (TCS)

LBA10012

Background: HG affects a substantial percentage of TCS and can contribute to significant morbidity, but few studies have examined the relationship between HG and adverse health outcomes (AHO), taking into account genetic variation. Methods: Eligible TCS were < 55 y at diagnosis and treated with only first line chemotherapy after 1990. TCS underwent physical exams and genotyping, and completed questionnaires regarding 16 AHO and health behaviors. HG was defined as serum testosterone ≤ 3.0 ng/mL or the use of testosterone replacement therapy. Results: We evaluated 491 TCS. Median age at evaluation was 38 y (range 19-68). 38.5% had HG. Two SNPs in the sex-hormone-binding globulin ( SHBG) locus previously implicated in increased HG risk in the general population (Ohlsson et al, PLOS Genetics 2011) displayed effect sizes consistent with prior reports (rs6258, OR = 1.3; rs12150660, OR = 0.79), but were not statistically significant. However, TCS with ≥ 2 risk alleles for the two SNPs in the SHBG locus vs no risk alleles had 2-fold increased risk for HG (OR = 2.2, P = .12). Multivariate analysis identified risk factors for HG including: age (OR = 1.4 per 10 year increase, P = .007), and BMI ≥ 25 kg/m2 (OR = 2.2, P = .003). Vigorous-intensity physical activity appeared protective (OR = 0.6, P = .06). Type of chemotherapy regimen and socioeconomic factors did not correlate with HG. Only 35% of TCS with HG vs 49% of those without HG reported none or 1 AHO ( P = .003). TCS with HG were more likely to take medications for dyslipidemia (20% vs 6%, P < .001), hypertension (19% vs 11%, P = .01), erectile dysfunction (ED) (20% vs 12%, P = .02), diabetes (6% vs 3%, P = .07), or anxiety/depression (15% vs 10%, P = 0.06) compared to TCS with normal levels, and also to have peripheral neuropathy (PN) (31% vs 23%, P = .04). HG status did not correlate with oto- or renal toxicity. Conclusions: Over a third of TCS have HG at a relatively young age. HG was associated with increased cardiovascular disease risk factors, ED, and PN. SHBG polymorphisms appear important in TCS, but our study was underpowered to confirm an association. Providers should screen TCS for HG and treat those who are symptomatic.

Clinical and Genome-Wide Analysis of Cisplatin-Induced Peripheral Neuropathy in Survivors of Adult-Onset Cancer

Purpose: Our purpose was to characterize the clinical influences, genetic risk factors, and gene mechanisms contributing to persistent cisplatin-induced peripheral neuropathy (CisIPN) in testicular cancer survivors (TCSs).Experimental Design: TCS given cisplatin-based therapy completed the validated EORTC QLQ-CIPN20 questionnaire. An ordinal CisIPN phenotype was derived, and associations with age, smoking, excess drinking, hypertension, body mass index, diabetes, hypercholesterolemia, cumulative cisplatin dose, and self-reported health were examined for 680 TCS. Genotyping was performed on the Illumina HumanOmniExpressExome chip. Following quality control and imputation, 5.1 million SNPs in 680 genetically European TCS formed the input set. GWAS and PrediXcan were used to identify genetic variation and genetically determined gene expression traits, respectively, contributing to CisIPN. We evaluated two independent datasets for replication: Vanderbilt's electronic health database (BioVU) and the CALGB 90401 trial.Results: Eight sensory items formed a subscale with good internal consistency (Cronbach α = 0.88). Variables significantly associated with CisIPN included age at diagnosis (OR per year, 1.06; P = 2 × 10^-9), smoking (OR, 1.54; P = 0.004), excess drinking (OR, 1.83; P = 0.007), and hypertension (OR, 1.61; P = 0.03). CisIPN was correlated with lower self-reported health (OR, 0.56; P = 2.6 × 10^-9) and weight gain adjusted for years since treatment (OR per Δkg/m², 1.05; P = 0.004). PrediXcan identified lower expressions of MIDN and RPRD1B, and higher THEM5 expression as associated with CisIPN (P value for each < 5 × 10^-6) with replication of RPRD1B meeting significance criteria (Fisher combined P = 0.0089).Conclusions: CisIPN is associated with age, modifiable risk factors, and genetically determined expression level of RPRD1B Further study of implicated genes could elucidate the pathophysiologic underpinnings of CisIPN. Clin Cancer Res; 23(19); 5757-68. ©2017 AACR.

Adverse health outcomes in relationship to hypogonadism (HG) after platinum-based chemotherapy: A multicenter study of North American testicular cancer survivors (TCS)

LBA10012

The full, final text of this abstract will be available at abstracts.asco.org at 2:00 PM (EDT) on Friday, June 2, 2017, and in the Annual Meeting Proceedings online supplement to the June 20, 2017, issue of the Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Saturday edition of ASCO Daily News.

Genome-wide association study (GWAS) of chemotherapy-induced Raynaud's phenomenon (RP) to reveal shared pathways with cardiovascular disease (CVD)

e18162

Background: RP is an adverse drug reaction characterized by reduced blood flow to the extremities causing pain and sensations of cold. Few studies have examined the genetic basis for RP, although family studies suggest a heritable component to primary RP. Methods: Eligible testicular cancer survivors (TCS) were < 55 y at diagnosis, treated with first line cisplatin-based chemotherapy, and completed questionnaires. Genotyping with standard quality control and imputation were performed. A case-control RP phenotype was derived from patient-reported outcomes and associations were computed by logistic regression. GWAS used cumulative bleomycin dose and 10 genetic principal components as covariates. Gene set enrichment analysis (GSEA) utilized genes ranked by the most significant GWAS SNP in/within 20 kilobases. A polygenic risk score for CVD derived from four prior independent GWAS (Khera et al. NEJM 2016) was assessed for association with RP. Results: Of 749 patients (median age 38 y, median time since chemotherapy 5 y), 38% reported RP. Bleomycin dose was the most significant predictor of RP (OR100 mg/m2 = 1.25, p < 0.0001). Number of years smoking also correlated with RP (ORyear = 1.05, p = 0.002). Age and hypertension showed no significant correlation with RP. GSEA revealed several significant pathways (FDR q < 0.1), including “ cellular response to VEGF stimulus” (q = 0.05) and “ cardiac muscle cell action potential” (q = 0.09). We hypothesized that RP may share genetic architecture with CVD. Deriving a polygenic risk score from genome-wide significant SNPs in prior CVD GWAS (n = 4260-22,389), we showed nearly significant case-control differences in CVD polygenic risk score (two-tailed t-test, p = 0.053). RP frequency significantly increased with polygenic risk score quartile (OR = 1.19, p = 0.008). Conclusions: Over one third of TCS report RP, with greater frequency among bleomycin-treated patients and smokers. Implicated genetic pathways include ones established in CVD. Although shared genetic risk between chemotherapy-induced RP and CVD may be possible, further investigation is required. Primary RP has been inconsistently linked with CVD.

Genome-Wide Association Studies of Chemotherapeutic Toxicities: Genomics of Inequality

With an estimated global population of cancer survivors exceeding 32 million and growing, there is a heightened awareness of the long-term toxicities resulting from cancer treatments and their impact on quality of life. Unexplained heterogeneity in the persistence and development of toxicities, as well as an incomplete understanding of their mechanisms, have generated a growing need for the identification of predictive pharmacogenomic markers. Early studies addressing this need used a candidate gene approach; however, over the last decade, unbiased and comprehensive genome-wide association studies (GWAS) have provided markers of phenotypic risk and potential targets to explore the mechanistic and regulatory pathways of biological functions associated with chemotherapeutic toxicity. In this review, we provide the current status of GWAS of chemotherapeutic toxicities with an emphasis on examining the ancestral diversity of the representative cohorts within these studies. Persistent calls to incorporate both ancestrally diverse and/or admixed populations into genomic efforts resulted in a recent rise in the number of studies utilizing cohorts of East Asian descent; however, few pharmacogenomic studies to date include cohorts of African, Indigenous American, Southwest Asian, and admixed populations. Through comprehensively evaluating sample size, composition by ancestry, genome-wide significant variants, and population-specific minor allele frequencies as reported by HapMap/dbSNP using NCBI PubMed and the NHGRI-EBI GWAS Catalog, we illustrate how allele frequencies and effect sizes tend to vary among individuals of differing ancestries. In an era of personalized medicine, the lack of diversity in genome-wide studies of anticancer agent toxicity may contribute to the health disparity gap. Clin Cancer Res; 23(15); 4010-9. ©2017 AACR.

Metabolic syndrome (MetS) after platinum-based chemotherapy (CHEM): A multicenter study of North American testicular cancer survivors (TCS)

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Background: Testicular cancer has an excellent prognosis since the introduction of platinum-based CHEM. However, several European studies report an excess of cardiovascular disease (CVD) in TCS. MetS is a cluster of cardiovascular risk factors that doubles CVD risk, with several European series noting a prevalence ranging from 13-39% in TCS. In the first large multi-center North American study of TCS, we examine the prevalence of and potential risk factors for MetS after modern CHEM (NCI R01 CA157823). Methods: Eligible TCS were <50 y at diagnosis and treated with only first line CHEM after 1990. TCS underwent physical exams, completed questionnaires regarding co-morbidities and health behaviors and had lipid panels, testosterone, and serum soluble cell adhesion molecule-1 (sICAM-1) measured. A single nucleotide polymorphism, rs523349 (V89L), in 5-α-reductase gene ( SRD5A2) previously suggested to associate with MetS in TCS was genotyped. MetS was defined as ≥3 of the following: hypertension (HTN), waist circumference ≥102 cm, triglycerides ≥150 mg/dL, HDL ≤40 mg/dL, and diabetes (Alberti et al, Circulation 2009). Controls (1:1) derived from the National Health and Nutrition Examination Survey were matched on age, race, and educational status. Results: We evaluated 486 consecutively enrolled TCS. Median age at evaluation was 38 y (range: 19-68). TCS had higher prevalence of HTN compared to controls (43% vs 31%, P < .01) but lower prevalence of low HDL (24% vs 35%, P < .01) and abdominal obesity (28% vs 40%, P < .01). Prevalence of MetS was comparable (21% TCS; 22% controls, P = .59). In multivariate analysis, age at evaluation (P < .01), serum testosterone <3.0 ng/mL (OR = 2.0, P = .005), and elevated sICAM-1 (OR for quartiles 2, 3, 4 vs lowest quartile: 2.7 (P = .01), 3.1 (P < .01), and 3.6 (P < .01), respectively) significantly correlated with MetS. The variant rs523349 (VL/LL) did not associate with MetS. Conclusions: One in 5 TCS treated with CHEM developed MetS. Providers should screen for MetS, adequately treat hypogonadism, HTN and hyperlipidemia, and encourage TCS to maintain a healthy lifestyle. Significant elevations in sICAM-1 underscore a role for inflammation in MetS.

Variants in WFS1 and Other Mendelian Deafness Genes Are Associated with Cisplatin-Associated Ototoxicity

Purpose: Cisplatin is one of the most commonly used chemotherapy drugs worldwide and one of the most ototoxic. We sought to identify genetic variants that modulate cisplatin-associated ototoxicity (CAO).Experimental Design: We performed a genome-wide association study (GWAS) of CAO using quantitative audiometry (4-12 kHz) in 511 testicular cancer survivors of European genetic ancestry. We performed polygenic modeling and functional analyses using a variety of publicly available databases. We used an electronic health record cohort to replicate our top mechanistic finding.Results: One SNP, rs62283056, in the first intron of Mendelian deafness gene WFS1 (wolframin ER transmembrane glycoprotein) and an expression quantitative trait locus (eQTL) for WFS1 met genome-wide significance for association with CAO (P = 1.4 × 10^-8). A significant interaction between cumulative cisplatin dose and rs62283056 genotype was evident, indicating that higher cisplatin doses exacerbate hearing loss in patients with the minor allele (P = 0.035). The association between decreased WFS1 expression and hearing loss was replicated in an independent BioVU cohort (n = 18,620 patients, Bonferroni adjusted P < 0.05). Beyond this top signal, we show CAO is a polygenic trait and that SNPs in and near 84 known Mendelian deafness genes are significantly enriched for low P values in the GWAS (P = 0.048).Conclusions: We show for the first time the role of WFS1 in CAO and document a statistically significant interaction between increasing cumulative cisplatin dose and rs62283056 genotype. Our clinical translational results demonstrate that pretherapy patient genotyping to minimize ototoxicity could be useful when deciding between cisplatin-based chemotherapy regimens of comparable efficacy with different cumulative doses. Clin Cancer Res; 23(13); 3325-33. ©2016 AACR.