Monitoring of Early Skin Reactions by Optical Coherence Tomography and Dermatoscopy in Patients Receiving Radiation Therapy for Head and Neck Cancer.

Purpose: Patients with head and neck cancer undergoing radiation therapy (RT) may experience pronounced acute skin reactions. We tested whether optical coherence tomography (OCT) and dermatoscopy could detect and monitor early subclinical RT-induced skin changes and might be used as a noninvasive prediction tool for higher-grade acute toxicity. Methods and Materials: Handheld OCT and dermatoscopy were used to monitor skin conditions during RT in head and neck cancer patients. Images were reviewed for typical and suspicious features facilitated by electronic image analyses. Radiation toxicity was graded weekly by a radiation oncologist. Machine learning was used to analyze the recorded data and to extract features, patterns/anomalies, and risk prediction values for high-grade radiation toxicity. Results: The most common skin features during RT observed by OCT were expressions of hyperkeratosis, blister formation, and in selected cases, formation of extensive microvascular structures or stratification disorder. Dermatoscopy revealed an almost linear increase in skin redness and saturation over the course of RT. By integrating all imaging and clinical data from RT weeks 1 to 3, it was possible to predict an increased risk of severe radiation toxicity (National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) grade 3 or higher) in the second half of RT. A prediction accuracy of 72%, 75%, and 77% was achieved with OCT and clinical assessment, dermatoscopy and clinical assessment, and all 3 modes combined, respectively. Conclusions: OCT and dermatoscopy can detect early radiation-induced skin changes at a subclinical level. Dermatoscopy is more accessible, whereas OCT requires training and further electronic processing to interpret images. Dermatoscopy, but not OCT, can quantify skin color changes, whereas OCT is able to deliver unique information on epidermal suspicious microstructural changes.