Assessment and Treatment Outcomes of Persistent Radiation-Induced Alopecia in Patients With Cancer

Persistent radiation-induced alopecia (pRIA) and its management have not been systematically described.To characterize pRIA in patients with primary central nervous system (CNS) tumors or head and neck sarcoma.A retrospective cohort study of patients from January 1, 2011, to January 30, 2019, was conducted at 2 large tertiary care hospitals and comprehensive cancer centers. Seventy-one children and adults diagnosed with primary CNS tumors or head and neck sarcomas were evaluated for pRIA.The clinical and trichoscopic features, scalp radiation dose-response relationship, and response to topical minoxidil were assessed using standardized clinical photographs of the scalp, trichoscopic images, and radiotherapy treatment plans.Of the 71 patients included (median [range] age, 27 [4-75] years; 51 female [72%]), 64 (90%) had a CNS tumor and 7 (10%) had head and neck sarcoma. Alopecia severity was grade 1 in 40 of 70 patients (56%), with localized (29 of 54 [54%]), diffuse (13 of 54 [24%]), or mixed (12 of 54 [22%]) patterns. The median (range) estimated scalp radiation dose was 39.6 (15.1-50.0) Gy; higher dose (odds ratio [OR], 1.15; 95% CI, 1.04-1.28) and proton irradiation (OR, 5.7; 95% CI, 1.05-30.8) were associated with greater alopecia severity (P < .001), and the dose at which 50% of patients were estimated to have severe (grade 2) alopecia was 36.1 Gy (95% CI, 33.7-39.6 Gy). Predominant trichoscopic features included white patches (16 of 28 [57%]); in 15 patients, hair-shaft caliber negatively correlated with scalp dose (correlation coefficient, -0.624; P = .01). The association between hair density and scalp radiation dose was not statistically significant (-0.381; P = .16). Twenty-eight of 34 patients (82%) responded to topical minoxidil, 5% (median follow-up, 61 [interquartile range, 21-105] weeks); 4 of 25 (16%) topical minoxidil recipients with clinical images improved in severity grade. Two patients responded to hair transplantation and 1 patient responded to plastic surgical reconstruction.Persistent radiation-induced alopecia among patients with primary CNS tumors or head and neck sarcomas represents a dose-dependent phenomenon that has distinctive clinical and trichoscopic features. The findings of this study suggest that topical minoxidil and procedural interventions may have benefit in the treatment of pRIA.