Table 5.
Criteria and radiation doses to the cochlea in correlation with the incidences of SNHL
| Study | RT | Criteria | Doses to cochlea | Median follow up & SNHL (per ear) |
|---|---|---|---|---|
| Kwong et al[10] | Conv RT + chemo (227 ears) |
>15 dB at each frequency | not defined | 30 months 24.2% |
| Oh et al [19] | Conv RT + chemo (48 ears) |
>15 dB at 4 kHz and PTA |
mean inner ear dose 66.2 ± 6.2 | 1 year 29.2% |
| Ho et al [12] | Conv RT + chemo (526 ears) |
>10 dB at 4 kHz and PTA |
estimated 70-91 Gy, 2.5-3.5 Gy/F |
4.5 years, 4 kHz 60% PTA 18% |
| Chan et al [5] | Conf RT vs Conf RT + chemo (170 ears) |
>15 dB at 4 kHz |
mean cochlea dose 33-71.7 Gy |
24 months 33.3% vs 55% (Conf RT vs Conf RT+ chemo) |
| Chen et al.[4] | Conf RT+ chemo (44 ears) |
>20 dB at one frequency >10 dB at two frequencies |
28.4 - 70.0 Gy | 29 months 57% |
| Our study | Conv RT +chemo vs IMRT+ chemo (134 ears, 68 patients) |
>15 db loss at 4 kHz and PTA |
Mean cochlea dose 25.09-75.54 Gy (IMRT) | 14 months 4 kHz Conv 48.75% IMRT 37% PTA Conv 5% IMRT 7.4% |
Conv RT = Conventional radiation therapy Conf RT = Conformal radiation therapy