Scalp hair repigmentation in the penumbral region of radiotherapy– a case series

Abstract

Introduction: Hair colour is determined by varying ratios of black-brown eumelanin and reddish-brown/reddish-yellow pheomelanin. Hair colour change has been reported with cancer therapies. Radiotherapy (RT) usually causes temporary epilation to permanent alopecia. A change in hair colour following radiation is rare and usually results in depigmentation. There has only been one other case reported of repigmentation after RT. Cases: We present five cases of changes to scalp hair pigmentation in the penumbral region in patients treated with volumetric modulated arc therapy (VMAT) for skin cancer. Five treated areas across four patients involved repigmentation from grey to black, and there was one case of depigmentation from brown to grey. The latter occurred during immunotherapy administration. For the two cases where recalculation of the dosimetry was possible for three areas, repigmentation changes happened at an average mean dose of 16 Gy (9.3 – 26 Gy) in an average of 26 (25 - 27) fractions; that is, 0.6 Gy per fraction at five fractions per week. Discussion: This series of six areas in five patients of hair colour change in the penumbral region of VMAT to the scalp for skin cancer is the first report of this phenomenon. Repigmentation of scalp hair with RT is rare. Even though rare, the potential for hair colour change may need to be part of the informed consent discussion in patients contemplating this treatment.