An 80-year-old woman presents with a right colon cancer that was found during a workup for anemia. She lives independently and walks 30 minutes a day. She had 1 fall in the last 6 months, from which she recovered well. She has hypertension, hyperlipidemia, and atrial fibrillation for which she takes a β-blocker, a statin, and warfarin. What should be used to stratify her surgical risk and make treatment decisions?