WASHINGTON — Sen. John McCain suffered a minor tear in his right Achilles tendon and was treated over the weekend at Walter Reed National Military Medical Center, his office says.

The 81-year-old Arizona Republican also was treated for "other normal and non-life-threatening side effects of cancer therapy,” a statement from his office says.

McCain is in his sixth Senate term and has brain cancer.

McCain was limping badly last week. The statement says he's back at work and will wear a walking boot until his injured tendon is fully healed.

McCain underwent surgery in mid-July to remove a 2-inch blood clot in his brain after being diagnosed with an aggressive tumor called a glioblastoma. It's the same type of tumor that killed Massachusetts Sen. Edward M. Kennedy at 77 in 2009.