Former Republican presidential nominee Mitt Romney was treated over the summer after a prostate cancer diagnosis, Fox News has confirmed.

An aide said Romney was surgically treated by Dr. Thomas Ahlering at UC Irvine Hospital. The treatment was successful and Romney’s prognosis is good, the person said.

"Last year, Governor Mitt Romney was diagnosed with slow-growing prostate cancer," an aide said. "The cancer was removed surgically and found not to have spread beyond the prostate."

The disclosure comes as Romney, the former governor of Massachusetts, is believed to be preparing to launch a campaign for Senate in Utah. GOP Utah Sen. Orrin Hatch recently announced he won’t seek re-election.

Romney – who owns homes in both states – changed the location on his Twitter account from Massachusetts to Utah the day Hatch announced his retirement.

The 70-year-old Romney hasn’t announced plans to run for the seat, but issued a statement last week praising Hatch.

“I join the people of Utah in thanking my friend, Senator Orrin Hatch for his more than forty years of service to our great state and nation,” Romney said.

Romney served as governor of Massachusetts from 2003 to 2007. He unsuccessfully sought the Republican nomination for president in 2008. He then was nominated by the Republican Party for president in 2012, but lost to then-President Barack Obama in the general election.

Romney and President Trump have had a tumultuous relationship. Trump endorsed Romney during the 2012 race, but Romney became a vocal critic of Trump during the 2016 election.

Romney was considered by Trump to serve as secretary of state last year, but the president passed him over for now-Secretary Rex Tillerson.

Amid reports of Romney's interest in the Utah seat, Trump publicly encouraged Hatch to seek another term. Since Hatch's announcement, however, Romney and Trump spoke by phone to discuss Hatch and the Senate seat, a White House official said.

Fox News' Kristin Brown and Amy Fenton contributed to this report.