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

Background Irreversible sensorineural hearing loss is a common side effect of platinum treatment with the potential to significantly impair the neurocognitive, social and educational development of childhood cancer survivors. Genetic association studies suggest a genetic predisposition for cisplatin-induced ototoxicity. Among other candidate genes, thiopurine methyltransferase (TPMT) is considered a critical gene for susceptibility to cisplatin-induced hearing loss in the FDA drug label and a pharmacogenetic guideline. The aim of this cross-sectional cohort study was to confirm the genetic associations in a large pan-European population and to evaluate the diagnostic accuracy of the genetic markers. Methods: Eligibility criteria required patients to be aged less than 19 years at the start of chemotherapy, which had to include cisplatin and/or carboplatin. Patients were assigned to three phenotype categories: no, minor, and clinically relevant hearing loss. Fourteen variants in eleven candidate genes (ABCC3, OTOS, TPMT, SLC22A2, NFE2L2, SLC16A5, LRP2, GSTP1, SOD2, WFS1, andACYP2) were investigated. Multinomial logistic regression was performed to model the relationship between genetic predictors and platinum ototoxicity, adjusting for clinical risk factors. Additionally, measures of the diagnostic accuracy of the genetic markers were determined. Findings: 900 patients were included in this study. In the multinomial logistic regression, significant unique contributions were found from SLC22A2 rs316019, the age at start of platinum treatment, cranial radiation, and the interaction term [platinum compound]*[cumulative dose of cisplatin]. Meta-analysis confirmed an allelic association of SLC22A2 rs316019 with cisplatin ototoxicity (odds ratio 1.46, 95% CI 1.10–1.95, p=0.009). Predictive performance of the genetic markers was poor, compared with the clinical risk factors. Interpretation: PanCareLIFE is the largest study of cisplatin-induced ototoxicity to date and confirmed a role for the polyspecific organic cation transporter SLC22A2. However, our study cannot recommend the use of any of the investigated genetic markers to guide the management and prevention of cisplatin-induced hearing loss. The study results will require a revision of the pharmacogenetic guideline and the FDA drug label. Funding Statement: This work was supported by the PanCareLIFE project that has received funding from the European Union’s Seventh Framework Programme for research, technological development, and demonstration under grant agreement no. 602030. CEK was funded by the Swiss Cancer Research Foundation (grant no. 4157-02-2017), the Swiss Cancer League (grant no. 3412-02-2014), the Bernese Cancer League, and the Lung League Bern. JFW received supplementary funding from the Danish Childhood Cancer Foundation and Soroptimist International Helsingor, Denmark. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The PanCareLIFE study has been approved by the local ethics committees: Kantonale Ethikkommission Bern, 362/2015; Comitate Etico Regionale, 507REG2014; Ethical Committee University Hospital Brno, June 11, 2016; Ethics Committee Fakultni Nemocnice v Motole, Prague; De Videnskabsetiske Komiteer Region Hovedstaden, H-1- 2014-125; Ethikkommission Medizinische Universitat Graz, 27-015 ex 14/15; Ethikkommission der Universitat Ulm, 160/17; Ethikkommission der Universitat zu Lubeck, 14/181; Ethik-Kommission der Arztekammer Westfalen-Lippe und der Westfalischen Wilhelms-Universitat Munster, 2014-619; Medische Ethische Toetsings Commissie Erasmus MC; Medisch Ethische Toetsingscommissie, 2015_202. The informed consent of the patient (if adult) or his/her legal representative has been obtained.