Hair mass index obtained by cross-section trichometry: an objective and clinically useful parameter to quantify hair...

In order to evaluate the efficacy of scalp cooling for the prevention of chemotherapy-induced alopecia (CIA), it is essential to precisely quantify the amount of hair mass that is present. We wanted to determine if the hair mass index (HMI), obtained by cross-section trichometry (CST), was a suitable parameter for hair mass measurement, and whether or not marking the measurement site on the scalp was necessary.

Ten patients receiving chemotherapy were sequentially measured using CST during their treatment. At the same time, they were asked to report severity of hair loss via three subjective parameters: World Health Organization (WHO) grade, visual analog scale (VAS) score, and patients' need to wear wig or head cover. To investigate the need of marking of the measurement area, differences in HMI between a random 2 × 2-cm site (HMI-C) and four surrounding areas (HMI-S4) on the scalp of eight volunteers and eight chemotherapy patients were calculated and compared.

Using CTS, hair loss due to CIA was quite measurable and ranged from 13 to 82 %. Reported VAS scores and WHO grades showed an increase in patients in time; 50 % of patients reported the need to wear a wig or head cover. The difference between HMI-S4 and the HMI-C values in all subjects of the marking group was homogeneously distributed between -11 and +10 and was not statistically different between the volunteer and the patient groups (p = 0.465).

CST for HMI measurement is a useful mechanical modality for assessing hair loss in CIA patients. It is quantitatively more precise than existing non-mechanical measuring methods. It is recommended when detection of minor changes in hair quantity is required. Marking a fixed sampling area to ensure return to the exact same site is only required when a minor change in pre- and posttreatment HMI values is anticipated and the mid-line locating device is not/cannot be used.