To assess the robustness of our findings, a sensitivity analysis using a clinically significant SNHL threshold (Chang ≥ 2a) was performed: both cochlear dose and cisplatin exposure remained associated with increased risk, though the former did not reach statistical significance (p = 0.07) due to reduced power while cisplatin exposure remained highly significant (HR = 6.21; p = 0.007).
In multivariate analysis adjusting for cisplatin exposure, Dmin showed a trend toward significance (HR = 6.77; 95% CI: 0.89–51.5; p = 0.065), while cisplatin remained independently associated with SNHL (HR = 4.35; 95% CI: 1.60–11.8; p = 0.004) (Table 4 ).
Although the comparison between mild and moderate/severe SNHL did not reach statistical significance (p = 0.56), likely due to the limited number of events, this finding supports a dose–severity relationship that extends beyond a simple binary outcome and reinforces the importance of minimizing cochlear dose whenever feasible.