Phil Lesh, who was bassist for the rock band Grateful Dead, canceled two concerts after revealing he has bladder cancer. In a letter to fans posted Friday on the Facebook page for Terrapin Crossroads, his restaurant and concert venue in San Rafael, California, Lesh said he was diagnosed with bladder cancer earlier this month. He said he has spent the last few weeks at the Mayo Clinic in Scottsdale, Arizona, doing tests ahead of surgery to remove the tumors. Lesh, 75, said his prognosis is positive.