New International Society of Pediatric Oncology Boston Ototoxicity Grading Scale for pediatric oncology: still room for improvement

Long-Term Variability of Distortion-Product Otoacoustic Emissions in Infants and Children and Its Relation to Pediatric Ototoxicity Monitoring

OBJECTIVE

Distortion-product otoacoustic emissions (DPOAEs) provide a rapid, noninvasive measure of outer hair cell damage associated with chemotherapy and are a key component of pediatric ototoxicity monitoring. Serial monitoring of DPOAE levels in reference to baseline measures is one method for detecting ototoxic damage. Interpreting DPOAE findings in this context requires that test-retest differences be considered in relation to normal variability, data which are lacking in children. This study sought to (1) characterize normal test-retest variability in DPOAE level over the long time periods reflective of pediatric chemotherapy regimens for a variety of childhood ages and f2 primary frequencies using common clinical instrumentation and stimulus parameters; (2) develop level-shift reference intervals; and (3) account for any age-related change in DPOAE level or measurement error that may occur as the auditory system undergoes maturational change early in life.

DESIGN

Serial DPOAE measurements were obtained in 38 healthy children (25 females and 13 males) with normal hearing and ranging in age from one month to 10 years at the initial (baseline) visit. On average, children were tested 5.2 times over an observation period of 6.5 months. Data were collected in the form of DP grams, in which DPOAE level was measured for f2 ranging from 1.4 to 10 kHz, using a fixed f2/f1 ratio of 1.22 and stimulus level of 65/55 dB SPL for L1/L2. Age effects on DPOAE level and measurement error were estimated using Bayesian regression of the longitudinal data. The raw and model-based distribution of DPOAE test-retest differences were characterized using means and standard error of the measurement for several ages and f2's.

RESULTS

DPOAE test-retest differences for the children in this study are at the high end of those previously observed in adults, as reflected in the associated shift reference intervals. Further, although we observe substantial child-specific variation in DPOAE level, the pattern of age-related changes is highly consistent across children. Across a wide range of f2's, DPOAE level decreases by 3 to 4 dB from 1 to 13 months of age followed by a more gradual decline of <1 dB/year. An f2 of 6 kHz shows the smallest decrease during the early rapid maturation period. DPOAE measurement error is fairly constant with age. It is 3 to 4 dB at most f2's and is greater (indicating poorer reliability) at 1.5, 8, and 10 kHz.

CONCLUSIONS

DPOAE level decreases with childhood age, with the greatest changes observed in the first year of life. Maturational effects during infancy and greater measurement error at very low and high f2's affect test-retest variability in children. An f2 of 6 kHz shows minimal maturation and measurement error, suggesting it may be an optimal sentinel frequency for ototoxicity monitoring in pediatric patients. Once validated with locally developed normative data, reference intervals provided herein could be used to determine screen fail criteria for serial monitoring using DPOAEs. Employing state-of-the-art calibration techniques might reduce variability, allowing for more sensitive screen fail criteria.

Comparison of radiation and chemoradiation-induced sensorineural hearing loss in head and neck cancer patients

Aim

The purpose of this study was to assess and compare the incidence and severity of sensorineural hearing loss (SNHL) in head-and-neck patients undergoing radiotherapy (RT) and concurrent cisplatin-based chemoradiotherapy (CRT).

Materials and Methods

Pure tone audiometry (PTA) was performed at 0.25-12 kHz on 35 RT and 25 CRT patients after 12-month followed up. The hearing loss was evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) criteria.

Results

SNHL increased to 84% in patients who had received CRT, compared with 26% increasing in patients who had treated with RT. There was an increased risk of SNHL at all frequencies for ears received a cochlear mean dose >50 Gy in RT group, compared to those receiving cochlear mean dose >30 Gy in CRT group. SNHL was more severe at higher frequencies in both patient groups.

Conclusion

Characteristic of radiation-induced SNHL is different from CRT-induced SNHL, especially in threshold radiation dose and PTA frequency.

Clinical trials, ototoxicity grading scales and the audiologist's role in therapeutic decision making

OBJECTIVES

Define clinical trials and adverse event (AE) monitoring from the perspective of the audiologist. Rationalise the importance of audiology's involvement before, during and after monitoring. Identify strengths and weaknesses in toxicity grading scales, and discuss factors that may influence these.

DESIGN

Literature involving commonly cited grading scales used to capture ototoxicity is reviewed. Current regulations and language associated with clinical trial implementation and AE monitoring are described. Personal observations based on a variety of clinical populations are drawn from years of experience developing and employing ototoxicity monitoring protocols in a complex medical setting.

RESULTS

Six commonly used grading scales for ototoxicity are systematically reviewed for strengths and weaknesses. Necessary considerations that inform selection of grading scales are presented. A review of and historical context for clinical trial development and AE monitoring is provided.

CONCLUSIONS

The audiologist's role in therapeutic decision making goes beyond collection of the audiogram. Clear communication to stakeholders in ototoxicity monitoring is paramount, and toxicity grading scales are one tool to facilitate this exchange. Various factors should be considered in advance of selecting the most appropriate scale to capture hearing loss, and no scale is without limitation.

Ototoxicity (cochleotoxicity) classifications: A review

OBJECTIVE

Drug-mediated ototoxicity, specifically cochleotoxicity, is a concern for patients receiving medications for the treatment of serious illness. A number of classification schemes exist, most of which are based on pure-tone audiometry, in order to assist non-audiological/non-otological specialists in the identification and monitoring of iatrogenic hearing loss. This review identifies the primary classification systems used in cochleototoxicity monitoring. By bringing together classifications published in discipline-specific literature, the paper aims to increase awareness of their relative strengths and limitations in the assessment and monitoring of ototoxic hearing loss and to indicate how future classification systems may improve upon the status-quo.

DESIGN

Literature review.

STUDY SAMPLE

PubMed identified 4878 articles containing the search term ototox*.

RESULTS

A systematic search identified 13 key classification systems. Cochleotoxicity classification systems can be divided into those which focus on hearing change from a baseline audiogram and those that focus on the functional impact of the hearing loss.

CONCLUSIONS

Common weaknesses of these grading scales included a lack of sensitivity to small adverse changes in hearing thresholds, a lack of high-frequency audiometry (>8 kHz), and lack of indication of which changes are likely to be clinically significant for communication and quality of life.

Short-term cohort study on sensorineural hearing changes in head and neck radiotherapy

The aim of this study was to investigate the risk of sensorineural hearing loss (SNHL) and the relationship between SNHL and radiation dose to the cochlea and frequency range of hearing loss in patients with head and neck cancer. Pure tone audiometry at 250-12,000 Hz was performed on 29 patients diagnosed with head and neck tumours who were treated with 3-dimensional conformal radiation therapy and followed up for 6 months. Paired t test indicated that the mean air conduction threshold before and after radiotherapy was significantly different (paired t test, p < 0.001). SNHL was observed in 15 patients (51 %) according to CTCAE. SNHL increased to 77 % in patients who had received at least five concurrent cisplatin cycles. There was an increased risk of SNHL for ears receiving a mean dose of 5000 cGy compared to those receiving <5000 cGy. SNHL was more severe at higher frequencies of pure tone audiometry in patients with cisplatin-based chemoradiation. The ototoxicity effect of radiation and cisplatin must be considered in the treatment of head and neck tumours. Increasing the dose of cisplatin, radiation dose of cochlea and follow-up interval time may result in increasing severity and frequency of hearing loss incidences. However, characteristic of radiation-induced SNHL seems to be different from chemoradiation-induced SNHL.

Evaluation of amifostine for protection against cisplatin-induced serious hearing loss in children treated for average-risk or high-risk medulloblastoma

BACKGROUND

The purpose of this study was to evaluate amifostine for protection from cisplatin-induced serious hearing loss in patients with average-risk medulloblastoma by extending a previous analysis to a much larger sample size. In addition, this study aimed to assess amifostine with serious hearing loss in patients with high-risk medulloblastoma treated with cisplatin.

METHODS

Newly diagnosed medulloblastoma patients (n = 379; ages 3-21 years), enrolled on one of 2 sequential St. Jude clinical protocols that included 4 courses of 75 mg/m(2) cisplatin, were compared for hearing loss by whether or not they received 600 mg/m(2) of amifostine immediately before and 3 hours into each cisplatin infusion. Amifostine administration was not randomized. The last audiological evaluation between 5.5 and 24.5 months following protocol treatment initiation was graded using the Chang Ototoxicity Scale. A grade of ≥ 2b (loss requiring a hearing aid or deafness) was considered a serious event.

RESULTS

Among average-risk patients (n = 263), amifostine was associated with protection from serious hearing loss (adjusted OR, 0.30; 95% CI, 0.14-0.64). For high-risk patients (n = 116), however, there was not sufficient evidence to conclude that amifostine prevented serious hearing loss (OR, 0.89; 95% CI, 0.31-2.54).

CONCLUSIONS

Although patients in this study were not randomly assigned to amifostine treatment, we found evidence in favor of amifostine administration for protection against cisplatin-induced serious hearing loss in average-risk but not in high-risk, medulloblastoma patients.

A New Grading System for Ototoxicity in Adults

Objective:

This study aimed to propose an ototoxicity grading system sensitive to the effect of ototoxicity on specific daily life situations like speech intelligibility and the perception of ultra-high sounds and to test its feasibility compared to current criteria.

Methods:

Pure tone averages (PTAs) for speech perception (1-2-4 kHz) and ultra-high frequencies (8-10-12.5 kHz) were incorporated. Threshold shift and hearing level posttreatment were taken into account. Criteria were tested on head and neck cancer patients treated with (chemo-)radiotherapy ([C]RT) and compared with the Common Terminology Criteria for Adverse Events version 4 (CTCAEv4) and the American Speech-Language-Hearing Association criteria (ASHA).

Results:

Grades 1 and 2 were based on threshold shifts from baseline (in dB) and subjective complaints. Grades 3 and 4 were defined as treatment-induced hearing loss of ≥ 35 dB at PTA 1-2-4 kHz and ≥ 70 dB at PTA 1-2-4 kHz, respectively. In high-dose cisplatin CRT incidences by the new criteria, CTCAEv4 and ASHA were comparable (78%-88%). In RT and low-dose cisplatin CRT, incidences were 36% to 39% in the new criteria versus 22% to 53% in CTCAEv4 and ASHA.

Conclusion:

The new criteria show an increased sensitivity to ototoxicity compared to CTCAEv4 and ASHA and provide insight into the effect of hearing loss on certain daily life situations. The new grading system seems feasible for clinic and research purposes.