Senator John McCain underwent surgery Sunday after contracing an intestinal infection.
The 81-year-old Arizona senator – who was diagnosed with brain cancer in July 2017 – remains in hospital in a stable condition, according to a statement released by his office.
“On Sunday, Senator McCain was admitted to Mayo Clinic in Phoenix, Arizona, and underwent surgery to treat an intestinal infection related to diverticulitis,” his office said.
“Over the last few months, Senator McCain has been participating in physical therapy at his home in Cornville, Arizona, as he recovers from the side effects of cancer treatment. He has remained engaged on his work as Chairman of the Senate Armed Services Committee and has enjoyed frequent visits from his family, friends, staff and Senate colleagues.”
“Senator McCain and his family are grateful to the senator’s excellent care team and appreciate the support and prayers they continue to receive from people all over the country.”
His daughter, Meghan McCain shared an update about her father’s health, tweeting on Monday, “My father @SenJohnMcCain is in stable condition – he continues to inspire me everyday with his intense grit and determination. Thank you to the doctors at Mayo Clinic in Phoenix and to everyone who is praying for him.”
RELATED VIDEO: Meghan McCain Opens Up About Wedding as John McCain Battles Brain Cancer
McCain was diagnosed with brain cancer after undergoing a surgery to remove a blood clot above his eye last summer. He was hospitalized in December to treat side effects related to his cancer therapy.
Biden reminded her to stay hopeful as there are medical breakthroughs all the time.
- Want to keep up on the latest from PEOPLE? Sign up for our daily newsletter to get our best stories of the day delivered straight to your inbox.
“And it can happen tomorrow,” said Biden, who added, “there is hope, and if anybody can make it, your dad… her dad is one of my best friends… The thing that I found, and Beau insisted on, and your dad’s going to insist on, is you’ve got to maintain hope. You have to have hope.”
After being diagnosed in July, McCain told PEOPLE that his daughter marrying Ben Domenech on Nov. 21 at the family’s ranch in Cornville, Arizona, was a dream come true. In the wake of the diagnosis, Meghan, 33, and Domenech, 35, made the decision to get engaged and quickly plan a wedding.