Evaluation of Radiobiological Effects in Skin Toxicities for Breast Cancer Patients With Pencil Beam Scanning Proton Therapy

During the study, digital photos of patients' skin will be taken to assess the amount of redness, without revealing their identity. Patients will be given a self-report questionnaire and medical staff will document the skin reactions in the patients' medical charts. The degree of skin reactions will be compared against historical occurrence rates, and the location of any skin reactions that occur will be compared against the predicted location from the computer model. In this study, we aim to test the hypothesis that the "Spot Delete" technique in proton therapy reduces radiation dermatitis in breast cancer patients compared to historical data from patients who underwent regular proton therapy without the technique. To evaluate this, we will compare the extent of skin reactions in patients who receive proton therapy with the "Spot Delete" technique to historical data from patients who did not receive this treatment. The effectiveness of the technique will be evaluated by measuring and documenting the degree of skin reactions in patients undergoing proton therapy with the Spot Delete technique. Digital photographs of the treatment area will be taken to assess radiation dermatitis using the treatment using the Common Terminology Criteria for Adverse Events (CTCAE) ver. 5.0 and using the Radiation Dermatitis Severity (RDS) scoring system. Radiation dermatitis will be assessed at baseline, weekly after every fifth treatment session, at the end of treatment, and at 2 post treatment follow-up appointments (e.g. 1-month and 6-months post treatment).These results will be compared to historical occurrence rates of skin reactions in regular proton therapy.