Non-Invasive Imaging in Post-Radiotherapy Monitoring of Non-Melanoma Skin Cancer

Non-melanoma skin cancers, including basal cell carcinoma and squamous cell carcinoma, are the most common forms of skin cancer worldwide. Though less aggressive than melanoma, they cause significant morbidity if untreated. Radiotherapy is a common treatment alternative for patients for whom surgery is contraindicated, particularly the elderly or those with tumors in anatomically challenging locations. Effective post-radiotherapy monitoring assesses treatment response, recurrence, and complications. Traditional post-radiotherapy monitoring often involves clinical examination and, if needed, invasive biopsies. Recently, noninvasive imaging modalities, such as reflectance confocal microscopy and line-field confocal optical coherence tomography, have gained attention. These technologies provide high-resolution, in vivo skin visualization. Reflectance confocal microscopy and line-field confocal optical coherence tomography offer complementary imaging data, facilitating the identification of residual tumor cells, inflammatory changes, and radiotherapy-induced skin alterations. They are valuable for follow-up as they monitor skin without biopsy. Early studies suggest high sensitivity and specificity in detecting treatment response and complications. Reflectance confocal microscopy and line-field confocal optical coherence tomography represent promising noninvasive tools for post-radiotherapy assessment of non-melanoma skin cancers. They enhance diagnostic accuracy, reduce the need for biopsies, and may improve patient outcomes through earlier detection of recurrence or complications. Further studies are warranted to standardize imaging criteria and validate their routine clinical use.