Clinical and genetic predictors of persistent chemotherapy-induced alopecia despite scalp cooling in breast cancer

Scalp cooling is commonly used to reduce chemotherapy-induced alopecia (CIA) and has been suggested to aid hair regrowth after treatment. However, a subset of patients still experience persistent CIA (PCIA) despite undergoing scalp cooling. In this post hoc analysis of two prospective trials, we investigated clinical and genetic factors associated with PCIA among 123 women with stage I–III breast cancer treated with anthracycline- and/or taxane-based chemotherapy and scalp cooling. PCIA, defined as incomplete hair regrowth at 6 months post-chemotherapy, was observed in 12% of patients. Tamoxifen monotherapy was identified as a strong independent risk factor (adjusted odds ratio, 11.66; 95% CI, 1.87–120.20), while variants in chr20p11 and HLA-DQB1 showed non-significant trends. Hair thickness remained significantly lower in the tamoxifen monotherapy. These findings suggest that tamoxifen may impair follicular recovery after chemotherapy, highlighting the importance of individualized counseling and close dermatologic follow-up in patients undergoing scalp cooling.