no one wants to be known for cancer, but a treatment can be. keytruda is known to treat cancer. fda-approved for 16 types of cancer, including certain early-stage cancers. one of those cancers is triple-negative breast cancer. keytruda may be used with chemotherapy medicines as treatment before surgery and then continued alone after surgery when you have early-stage breast cancer and are at high risk of it coming back. keytruda can cause your immune system to attack healthy parts of your body during or after treatment. this may be severe and lead to death. see your doctor right away if you have cough, shortness of breath, chest pain, diarrhea, severe stomach pain, severe nausea or vomiting, headache, light sensitivity, eye problems, irregular heartbeat, extreme tiredness, constipation, dizziness or fainting, changes in appetite, thirst, or urine, confusion, memory problems, muscle pain or weakness, fever, rash, itching, or flushing. there may be other side effects. tell your doctor about all your medical conditions, including immune system problems, if you've had or plan to have an organ or stem cell transplant, received chest radiation,