Sensorineural hearing loss in combined modality treatment of nasopharyngeal carcinoma.
BACKGROUND
Combined modality therapy has become the standard of care for nasopharyngeal carcinoma, yet the combined ototoxic effects of radiation and cisplatin are poorly understood. The incidence and severity of sensorineural hearing loss (SNHL) with combined modality therapy was evaluated and the dose-response relation between radiation and hearing loss was investigated.


METHODS
Patients with newly diagnosed AJCC Stage II-IVB nasopharynx carcinoma treated from 1994-2003 were identified. The records of 44 ears in 22 patients who received a preirradiation pure tone audiogram and followup audiograms 12+ months postirradiation were included in the analysis. All patients were treated with conformal radiotherapy to 70 Gy and received platinum-based chemotherapy similar to the Intergroup 0099 trial. Composite cochlear dose distributions were calculated. Ototoxicity was measured using intrasubject audiogram comparisons and SNHL was defined as per the American Speech and Hearing Association guidelines, with standard range of speech between 2000-4000 Hz. SNHL was analyzed using Fisher exact test and linear and logistic regression models.


RESULTS



METHODS
median age, 45; 27% Asian; 68% male; 64% WHO III. Median audiologic followup was 29 months (range, 12-76 mos). Mean cochlear dose (Dmean) ranged from 28.4-70.0 Gy (median, 48.5 Gy). SNHL was detected in 25 of the 44 ears (57%) studied. There was an increased risk of SNHL for ears receiving Dmean > 48 Gy compared with those receiving < or = 48 Gy at all frequencies within the range of speech (P = 0.04). Using univariate logistic regression analysis, Dmean to the cochlea, cycles of cisplatin, and time postradiotherapy were independently significant factors in determining the incidence of SNHL (P = 0.02, P = 0.03, and P = 0.04, respectively). In univariate and multivariate linear regression analysis, Dmean was statistically significant at all frequencies in affecting degree of SNHL, whereas the significance of cisplatin and time was variable.


CONCLUSIONS
There was a significant increase in risk of SNHL among patients receiving > 48 Gy, suggesting a threshold in cochlear radiation dose-response in the setting of combined modality therapy. This dose should serve as a Dmean constraint maximum for intensity-modulated radiotherapy treatment of nasopharynx carcinoma.
Chen
William C
WC
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Jackson
Andrew
A
Budnick
Amy S
AS
Pfister
David G
DG
Kraus
Dennis H
DH
Hunt
Margie A
MA
Stambuk
Hilda
H
Levegrun
Sabine
S
Wolden
Suzanne L
SL
D000293:Adolescent; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects* / Q000627:therapeutic use; D001299:Audiometry; D002277:Carcinoma / Q000188:drug therapy* / Q000532:radiotherapy*; D002945:Cisplatin / Q000008:administration & dosage / Q000009:adverse effects; D003131:Combined Modality Therapy / Q000009:adverse effects; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy*; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D012189:Retrospective Studies; D012720:Severity of Illness Index
D002945:Cisplatin