A Study of GR1014 Cutaneous Gel for the Prevention of Skin Reactions Caused by Radiation Therapy for Breast Cancer

This clinical trial is testing a new skin gel called GR1014-CG to evaluate its safety and see if it can help prevent or reduce skin irritation (such as redness, soreness, etc.) caused by radiation therapy (RT) after breast-conserving surgery for early-stage breast cancer. The study is for women aged 18 and older who have had surgery to remove a breast tumor and need radiation therapy. The main goals of the study are to find out: * If GR1014-CG is safe to use * If the gel can prevent or lower the severity of skin irritation caused by RT. During the study participants will, * Be randomly assigned to use one of two strengths of GR1014-CG (4.7% or 2.4%) or a placebo gel (a gel with no active drug). * Apply the gel to the breast before each radiation session for 5 days. * Visit the clinic once a week for 4 weeks to check their skin and overall health. At the end of the 4th week, if there are still signs of irritation participants will come to the clinic for a checkup 2 weeks after, and then again 2 weeks after if the irritation is still observed. * Keep a diary to record any pain or itching they may feel.