title: Monitoring carboplatin ototoxicity with distortion-product otoacoustic emissions in children with retinoblastoma.
abstract: OBJECTIVE
  Carboplatin is a common chemotherapy agent with potential ototoxic side effects that is used to treat a variety of pediatric cancers, including retinoblastoma. Retinoblastoma is a malignant tumor of the retina that is usually diagnosed in young children. Distortion-product otoacoustic emission tests offer an effective method of monitoring for ototoxicity in young children. This study was designed to compare measurements of distortion-product otoacoustic emissions obtained before and after several courses of carboplatin chemotherapy in order to examine if (a) mean distortion-product otoacoustic emission levels were significantly different; and (b) if criterion reductions in distortion-product otoacoustic emission levels were observed in individual children.
  
  
  METHODS
  A prospective repeated measures study. Ten children with a median age of 7.6 months (range, 3-72 months) diagnosed with unilateral or bilateral retinoblastoma were examined. Distortion-product otoacoustic emissions were acquired from both ears of the children with 65/55 dB SPL primary tones (f(2)=793-7996 Hz) and a frequency resolution of 3 points/octave. Distortion-product otoacoustic emission levels in dB SPL were measured before chemotherapy treatment (baseline measurement) and after 3-4 courses of chemotherapy (interim measurement). Comparisons were made between baseline and interim distortion-product otoacoustic emission levels (collapsed across ears). Evidence of ototoxicity was based on criterion reductions (≥ 6 dB) in distortion-product otoacoustic emission levels.
  
  
  RESULTS
  Significant differences between baseline and interim mean distortion-product otoacoustic emission levels were only observed at f(2) = 7996 Hz. Four children exhibited criterion reductions in distortion-product otoacoustic emission levels.
  
  
  CONCLUSIONS
  Mean distortion-product otoacoustic emission levels at most frequencies were not changed following 3-4 courses of carboplatin chemotherapy in children with retinoblastoma. However, on an individual basis, children receiving higher doses of carboplatin exhibited criterion reductions in distortion-product otoacoustic emission level at several frequencies. These findings suggest that higher doses of carboplatin affect outer hair cell function, and distortion-product otoacoustic emission tests can provide useful information when monitoring children at risk of developing carboplatin ototoxicity.
authors.affiliation: School of Audiology and Speech-Language Pathology, The University of Memphis, Memphis, TN, United States. sbhagat@memphis.edu
authors.forename: Shaum P
authors.initials: SP
authors.lastname: Bhagat
authors.forename: Johnnie K
authors.initials: JK
authors.lastname: Bass
authors.forename: Stephanie T
authors.initials: ST
authors.lastname: White
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Qaddoumi
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Wilson
authors.forename: Jianrong
authors.initials: J
authors.lastname: Wu
authors.forename: Carlos
authors.initials: C
authors.lastname: Rodriguez-Galindo
mesh_terms: D000970:Antineoplastic Agents / Q000009:adverse effects*; D001299:Audiometry / Q000379:methods; D016190:Carboplatin / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D005260:Female; D034381:Hearing Loss / Q000139:chemically induced* / Q000175:diagnosis*; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000187:drug effects; D010865:Pilot Projects; D011237:Predictive Value of Tests; D019572:Retinal Neoplasms / Q000188:drug therapy*; D012175:Retinoblastoma / Q000188:drug therapy*
chemical_list: D000970:Antineoplastic Agents; D016190:Carboplatin