5 vs. 9-day Course of Whole Breast Radiotherapy With Boost for Early-stage Breast Cancer

This study is comparing two schedules of radiation therapy after lumpectomy (breast-conserving surgery): a 5-day course versus a 9-day course — both of which are much shorter than the traditional multi-week approach. Researchers want to find out if a 5-day schedule works just as well for women with breast cancer who have certain higher-risk features. **You may be eligible if...** - You are a woman aged 18 or older - You have been diagnosed with invasive breast cancer or DCIS (early-stage non-invasive breast cancer) - Your cancer is stage T0–T3, N0, M0 (early-stage, no lymph node spread, no distant spread) - You had a lumpectomy within the past 84 days with clear surgical margins - You have at least one higher-risk feature (e.g., grade 3 cancer, low hormone receptor levels, lymphovascular invasion, close margins, or you are 50 or younger) **You may NOT be eligible if...** - You have cancer in both breasts - You had prior radiation to the chest - You had prior chemotherapy - Your cancer has spread to lymph nodes or other organs - You had a prior breast cancer in either breast - You have severe heart disease or a recent stroke or blood clot Talk to your doctor to see if this trial is right for you.