Troubling news for Deadheads: Grateful Dead bassist Phil Lesh has been diagnosed with bladder cancer and is being treated in Arizona. The 75-year-old bassist announced his illness Friday on the Facebook page of his California restaurant and concert hall, Terrapin Crossroads. Lesh, diagnosed early this month, has been undergoing tests at the Mayo Clinic in Scottsdale. "I am very fortunate to have the pathology reports show that the tumors are all non aggressive, and that there is no indication that they have spread," he writes. Lesh will eventually need surgery, however, and he canceled Phil Lesh and Friends shows scheduled for Oct. 24 and 25 at the Terrapin Crossroads in San Rafael. (More Grateful Dead stories.)