Background  Antineoplastic treatment for breast cancer is frequently associated with alopecia. Increasingly, changes in the texture and shape of regrowing hair after chemotherapy have been reported, without evaluation on a scientific basis. Optical coherence tomography (OCT) provides highly reproducible measurements of hair shaft parameters.

Objectives  This study aims to evaluate hair shaft alterations using OCT in chemotherapy-induced alopecia and in patients taking tamoxifen.

Methods  The measurements of this prospective case series were performed on women aged 29–68 years, receiving either tamoxifen (n 17) or chemotherapy (n 17) prior to (T1) and after (T2) treatment. Each time, 20 hairs from two different sites of the scalp (frontal, occipital) were examined by OCT. The hair parameters were characterized by cross section (CS) and form factor (FF). The ratio of maximal to minimal hair diameters determined the FF.

Results  After chemotherapy, the CS of hairs was significantly lower compared with hairs taken at T1. The FF did not vary between T1 and T2 for the frontal area, but it did for the occipital area. In patients treated with tamoxifen, changes were observed neither in CS nor in FF. However, comparing both therapeutic groups, there were significant differences in CS and FF for T2, but not for T1.

Conclusions  Reported changes in hair structure after chemotherapy may be due to reduction of hair shaft calibre and increase of FF in regrowing hair. The OCT technique is a promising method to gain more insight into chemotherapy-induced changes of hair morphology.