(CNN) US Senate candidate Kelli Ward, who is challenging Arizona Sen. Jeff Flake in the state's 2018 Republican primary, said Thursday that she hopes Sen. John McCain will step aside as quickly as possible following the news this week of his brain cancer diagnosis.

Ward, who failed in her effort to unseat McCain during last year's primary, also floated the possibility that she would be appointed to McCain's seat should he resign.

"I hope that Senator McCain is going to look long and hard at this, that his family and his advisers are going to look at this, and they're going to advise him to step away as quickly as possible," she said on Indiana radio WOWO 1190 AM . "So that the business of the country and the business of Arizona being represented at the federal level can move forward."

McCain, 80, was recently diagnosed with an aggressive form of brain cancer. The news of his diagnosis, revealed on Wednesday, was met with an outpouring of sympathy from members of both parties. Ward tweeted on Wednesday after the diagnosis was revealed that she wished him and his family "comfort and peace."

In Thursday's interview, she said President Donald Trump agenda "can't be at a standstill while we wait for John McCain to determine what he's going to do."

"Because you probably realize that with John McCain out of commission we don't have 51 votes on the Republican side," she said, though McCain's absence does still leave Republicans with 51 votes in the Senate. "That can't stand. We can't have until the 2018 election, waiting around to accomplish the 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 and we can't be at a standstill while we wait for John McCain to determine what he's going to do."

Ward, an osteopathic physician and former Arizona state senator, told CNN on Monday that she has talked to White House officials about her run against the incumbent Flake, who, along with McCain, has been one of Trump's staunchest Republican critics. Flake called on Trump to withdraw from the presidential race after the release of the "Access Hollywood" tape, which showed Trump making lewd comments about women.

She speculated in Thursday's radio interview that it was unlikely that he would be able to return to the Senate "at full force."

"I would never presume to say what someone's prognosis is without having exams," she said. "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. That likelihood is low. So in our state, we don't have a quick special election or anything if someone retires or resigns or steps away from their position."

She added that if McCain steps down she hopes Arizona Gov. Doug Ducey considers appointing her to his seat until an election takes place in 2018 to decide who would fill it for the remainder of his term.

"Well, you know, I certainly hope so," she said. "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. And you know, I made an extremely good showing against Senator McCain against all odds. You know, he outspent me nearly 10 to 1. He has a super PAC called Grassroots Action PAC that spent over 10 million dollars seeking to destroy my character, my reputation, and my political future."

She continued, "However, I have emerged from those ashes much stronger and really I am beating the pants off of Jeff Flake already. And you know, some people told me that Jeff Flake would do well to encourage the governor to appoint me because that would take the pressure off of him."

In a statement to CNN, Flake said, "John McCain is a fighter and an American hero. I fully expect to see him back in the senate soon. I'm dumbstruck by Kelli Ward's comments."

A McCain spokesperson declined to comment.