WASHINGTON, D.C.: US Senator John McCain, who is battling brain cancer, was in stable condition on Monday (Tuesday in Manila) after undergoing surgery to treat an infection, an aide said, adding that Senate colleagues have made frequent visits to see him. McCain’s spokesperson Julie Tarallo said that McCain was admitted to Mayo Clinic in Phoenix, Arizona on Sunday and underwent surgery to treat an intestinal infection related to diverticulitis. McCain, 81, was diagnosed last year with an aggressive type of cancer, glioblastoma, after a brain tumor was discovered by doctors. It has led to a reduced role in Congress for the veteran lawmaker, who was the Republican presidential nominee in 2008 and currently chairs the powerful Senate Armed Services Committee. His wife Cindy McCain took to Twitter to say that her husband was “doing well after his surgery. Looking forward to getting back to Hidden Valley,” the couple’s ranch in Arizona.