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Association Between EGFR-TKI-Associated Skin Rash and Recorded Mortality in Non-Small Cell Lung Cancer: A Real-World
Yasutaka Ihara1,2,3, Yukihiro Nakamura4, Shoichiro Yamamoto4,5
1Clinical Research Promotion Unit, Clinical Therapeutic Trial Center, Ehime University Hospital, Toon, Ehime, Japan.
Purpose:
Skin rash during epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) therapy has been associated with better outcomes in non-small cell lung cancer (NSCLC), but previous studies may have overestimated this association because of immortal time bias. We evaluated the association between EGFR-TKI-associated skin rash and mortality while accounting for rash timing.
Methods:
We identified patients with NSCLC who initiated first-line EGFR-TKIs between August 2018 and December 2024 using a Japanese claims database. EGFR-TKI-associated skin rash was defined using a qualifying diagnosis and rash-related treatment recorded in the same calendar month. We performed time-dependent propensity score sequential matching: each patient who newly developed skin rash was matched on the rash-onset day to patients still at risk who had not yet developed skin rash; follow-up started on the matched day. For comparison, we also performed an analysis that did not account for immortal time bias and landmark analyses.
Results:
Among 11 830 eligible patients, 560 developed incident skin rash. In the time-dependent propensity score sequential matching analysis, 560 patients with skin rash were matched to 5600 patients without skin rash, and skin rash was associated with lower recorded mortality (HR, 0.621; 95% CI, 0.404-0.953). The estimate was stronger in the analysis not accounting for immortal time bias (HR, 0.410), whereas the association was attenuated in landmark analyses.
Conclusions:
EGFR-TKI-associated skin rash was associated with lower recorded mortality, but the association was weaker after accounting for immortal time bias. Prior studies may have overestimated this association.
