Looking for complementary alternatives to CTCAE for skin toxicity in radiotherapy: quantitative determinations

Radiotherapy (RT) is an essential part of the patient's treatment diagnosed with cancer. Determination of the most common RT secondary effect, the cutaneous toxicity, is usually based on visual rating scales, like Common Terminology Criteria for Adverse Events with an inherent subjectivity. The aim of this work is to perform an objective method to evaluate the radiodermatitis using a non-invasive imaging technique based on laser Doppler flowmetry (LDF).

A prospective study was performed analysing 1,824 measurements. A LDF was used to measure the cutaneous microcirculation in real time. A basal measurement was taken prior to radiotherapy treatment. To be able to observe the microcirculation changes related to the delivered dose, several sets of measurements were taken in the irradiated area along the RT treatment and in the contralateral non-irradiated area.

A relative increase in blood flow at all measured points was found in the irradiated area. This relative increase in blood flow increases with the dose administered. In the non-irradiated contralateral area, the relative increase in blood flow is not significant and is independent of the dose administered. After treatment, a decrease in blood flow was detected with a trend towards returning to the baseline measurements.

LDF is an objective technique that assesses early radiodermatitis. This method is useful to develop strategies to prevent onset of radiation dermatitis in patients irradiated, such as the modification and individualization of fractionation parameters of the RT. This allows the reduction of radiation morbidities and maintains patient quality of life.