Background: The incidence and severity of baseline hearing abnormality in HNCP is poorly characterized, as is the subsequent CDDP associated hearing loss. While formal behavioral audiograms can characterize CDDP associated hearing loss in great detail, most oncologists either rely on subjective evaluation of hearing loss or grade hearing impairment using the CTCAE. Two new grading systems for grading cisplatin ototoxicity have been developed for use in pediatrics, the Brock and Chang systems. This report is the first evaluation of these 3 hearing loss criteria in an adult cancer patient population. Methods: We conducted an electronic medical records (EMR) search for all HNCP between 2004 and 2010 treated at the Stanford Cancer Institute (SCI) and identified which patients had audiograms in the EMR, and who had received CDDP. Three investigators (RL, ADC, KC) independently graded these audiograms using the CTCAE v3 and v4, Brock and Chang criteria. Baseline distributions, changes following CDDP dosing, and inter-observer variability were calculated for hearing impairment grading using all four criteria. Results: We evaluated 460 audiograms in 111 patients. Because 282/460 of the audiograms did not have threshold shifts measured at 1,2,3,4,6 and 8 kHz, CTCAE v4 could not be applied to them . We therefore limited all further comparisons to CTCv3, Brock and Chang criteria. The table below summarizes the analysis. Conclusions: The Brock and Chang ototoxity criteria scales deliver a distribution of hearing AE grades at baseline more compatible than the CTCAE v3 with respect to the expectation that most HNCP do not have severe baseline hearing loss. Both the Brock and Chang scales are more sensitive than the CTCv3 to CDDP associated hearing changes. The Brock scale, followed by the Chang scale, demonstrated highest inter-rater agreement. Additional data concerning performance characteristics and utility of these three grading systems will be presented. Replacement of the present hearing impairment criteria in the CTCAE with either the Brock or Chang scales should be considered.

Ototoxicity scale	CTCAE v3	Brock	Chang
Baseline median grade	2	0	0
% inter-rater agreement	69	91	80
% with grade changes following CDDP	33	44	47