Republican U.S. Senate challenger Kelli Ward, who last year generated a national backlash after calling U.S. Sen. John McCain "old" and "weak" and suggesting he is likely to die in office, is now saying the ailing McCain should quit and let Gov. Doug Ducey appoint a replacement.

Speaking on WOWO-AM (1190) in Indiana, Ward, a former state senator from Lake Havasu City, said she should be considered for McCain's Senate job.

"Because I have a proven track record of years in the state Senate of being extremely effective and of listening to the voice of the people that I represent," Ward said in the interview that subsequently was reported nationally by CNN. "And you know, I made an extremely good showing against Senator McCain against all odds."

On his way to winning a sixth Senate term, McCain, R-Ariz., defeated Ward in the 2016 GOP primary election by 66,544 votes despite her late attack on his health and age. Almost immediately, she started running against the state's other Republican incumbent, U.S. Sen. Jeff Flake, in the 2018 primary.

McCain, the 2008 Republican presidential nominee who turns 81 on Aug. 29, this week was diagnosed with a brain tumor known as a glioblastoma, an aggressive and deadly form of brain cancer.

McCain has signaled that he intends to continue in his role as a senator and tweeted Thursday that he'll be back soon.

"I would never presume to say what someone's prognosis is without having exams," Ward, a 48-year-old doctor, said in the radio interview. "As a Christian, I know there can always be miracles. But the likelihood that John McCain is going to come back to the Senate and be at full force for the people of our state and the people of the United States is low."

Flake, 54, responded to Ward with a written statement to The Arizona Republic.

"John McCain is a fighter and an American hero. I fully expect to see him back in the Senate soon," Flake said. "I’m dumbstruck by Kelli Ward’s comments.”

Julie Tarallo, McCain's Senate spokeswoman, declined to comment on Ward's call for McCain to leave office.

On Friday afternoon, Ward put out a written statement in which she said her prayers are with McCain and his family and added that "these end-of-life choices are never easy."

"The medical reality of his diagnosis is grim. Senator McCain has an aggressive brain cancer that is both devastating and debilitating," she said. "When the time comes that Senator McCain can no longer perform his duties in the Senate at full capacity, he owes it to the people of Arizona to step aside."

Ward said she usually advises terminal patients "to reduce stress, relax, and spend time laughing with loved ones."

"The Senate has complicated and difficult problems to deal with and Arizona deserves to be represented by someone who can focus on those challenges," Ward added. "I hope and pray that Senator McCain will be comfortable as he battles this terrible disease."

In the event that McCain cannot finish his six-year term, which expires in 2023, Ducey would tap a Republican successor who would face voters in the next general election. That means there is at least a possibility that Arizona voters would elect two U.S. senators in the upcoming 2018 election.

"We can't have until the 2018 election, waiting around to accomplish the (President Donald) Trump agenda, to secure the border and stop illegal immigration and repeal 'Obamacare' and fix the economy and fix the Veterans Administration, all those things need to be done," she said in the radio interview. "And we can't be at a standstill while we wait for John McCain to determine what he's going to do."

Ward quickly got blowback on Twitter, where users of the social-media platform described her as "no class," "gross" and "vile" for positioning herself for McCain's seat while he recovers from cranial surgery.

Ward's biting remarks on McCain's age and health in the waning days of last year's primary campaign also got her a round of negative national publicity.

The Washington Post called it "one of the nastiest political attacks you’ll ever see."

"So she's saying he's going to die in office? ... Wow," Mika Brzezinski of MSNBC's "Morning Joe" said at the time.

"I mean, that's sick. Someone needs to take her diagnosis."

Nowicki is The Republic's national political reporter. Follow him on Twitter, @dannowicki.