My husband, Ken, was on Keytruda for one year. Scan results were very good until the last two months. Two tumors began to grow rather than shrink. However, the 50+ smaller ones under his arm are now gone. We are thrilled to be dealing with only two tumors now. At this point, radiology is an option. We consult with a radiologist tomorrow. The Keytruda side effects were minimal. He had two squamous cells cancers on his leg that needed MOHS surgery. He also had some rashes that were managed with various creams and ointments.