Sen. Chuck Schumer called on the federal government and drug manufacturer Merck to address what he called a “critical shortage” of a bladder cancer drug. The New York Democrat spoke Monday at the University of Rochester Medical Center alongside health care providers and a bladder cancer patient, Bill Burchell. Burchell, who lives in Webster, said he found out he had bladder cancer eight months ago. He got the news from doctors at URMC, who told him the type of cancer he had was aggressive. But