DESCARTES: De-ESCAlation of RadioTherapy in Patients With Pathologic Complete rESponse to Neoadjuvant Systemic Therapy

This study is exploring whether women with breast cancer who have a complete response to pre-surgery chemotherapy (meaning no cancer is found in the removed tissue) can safely reduce or skip radiation therapy after surgery. The goal is to avoid unnecessary radiation side effects in patients who may no longer need it. **You may be eligible if...** - You are a woman aged 18 or older - You have invasive breast cancer (hormone receptor positive, HER2+, or triple negative) - You received chemotherapy before surgery (neoadjuvant therapy) - After surgery, pathology confirmed no remaining invasive cancer (complete pathological response) **You may NOT be eligible if...** - Cancer was still found in the breast or lymph nodes after surgery - You have had prior breast cancer or radiation to the chest - You have inflammatory breast cancer - You are pregnant - You have a condition that makes radiation especially risky Talk to your doctor to see if this trial is right for you.