At the time of the diagnosis in February 2019, the then 18-year-old had established herself as one of Japan’s poster athletes for the imminent Tokyo Olympics having won six golds and two silvers at the 2018 Asian Games in Jakarta and Palembang, where she was named the most valuable player of the multi-sport event.

Ikee was released from hospital in January 2020, saying she would be focusing on qualifying for the Paris 2024 Olympics.

The postponement of the Tokyo 2020 Games offered her a theoretically improved chance to compete in a second Games after Rio 2016, where she broke the Japanese 100 metres butterfly record three times, clocking 56.86sec as she finished sixth in the final.

But Ikee had to wait until a week after that postponement was announced in March last year even to get back into the water.

When in January of this year her performance at the Tokyo Open meeting narrowly qualified her for the National Championships and Olympic trials currently underway in the capital, she remained downbeat about her chances of making her home Games.

"I wanted to qualify for the nationals and I'm glad that I did but I finished fourth again - it's really frustrating," said Ikee.

"It's a tough loss but I can only get better from here.

"This was a painful reminder that competition is unforgiving.

"It's not about my aiming for the Tokyo Olympics, but focusing on the task at hand, calmly putting in the work in practice."

At the trials, Ikee returned to the position with which she had become familiar in the years before her illness - the top of the podium. 

Her 100m butterfly victory in 57.77 was outside the Olympic qualifying time of 57.10 for the event but inside the Games qualifying time of 57.92 for the 4x100 medley team.

And she will have further chances to earn an individual Olympic place when she competes in the 50m and 100m freestyle events at the trials.

Ikee was in tears after her 100m butterfly performance.

"I didn't know what had just happened," she said. "It was a feeling I had never experienced before.

"I didn't think I had a chance in the butterfly at all. I thought if I was to get in it might be the 100m freestyle relay.

"I thought if it wasn't to be, it wasn't to be. If I did get in it would be good experience to take to the next Olympics."

Just hours after Ikee had announced her diagnosis on Instagram, Japan's then Olympics Minister Yoshitaka Sakurada made a crass statement about the news for which he was later to apologise - what is it about this particular position in Japanese sport?

"She is a potential gold medallist, an athlete in whom we have great expectations," the 69-year-old told Kyodo News. "I'm really disappointed.

"When one person leads, she can boost the whole team. I am slightly worried that this type of excitement could wane."

Now the young athlete who so selfishly threatened to diminish the "excitement" of her Japanese team-mates by getting ill is able to approach these postponed Games as a figure who is even more inspirational than the all-conquering 18-year-old she once was.

This time round the inspiration is international, as evidenced by the messages on social media prompted by the news of her qualification.

"Olympians never give up," said the big cheese himself, International Olympic Committee President Thomas Bach. "Congratulations to cancer survivor Rikako Ikee for qualifying for the Tokyo Olympics only two years after being diagnosed with leukemia. Can't wait to see you in Tokyo."

Sweden’s Sarah Sjostrom, winner of that Rio 2016 100m butterfly final in a world record of 55.48, called Ikee "amazing". 

Denmark's Olympic 50m freestyle champion Pernille Blume told Ikee she was "proud" of her, while South Africa's Chad le Clos, the London 2012 200m butterfly champion, described the news as "inspirational" on his Instagram account.

Ikee thus takes her place among a select group of elite sportsmen and women who have returned to the highest levels of competition after overcoming potentially life-threatening illness.

Fellow swimmer Eric Shanteau was diagnosed with testicular cancer a week before the United States' 2008 Olympic trials and qualified there before having surgery.

He swam a personal best in Beijing in the 200m breaststroke, and went on to win Olympic and world gold as part of the US 4x100m medley relay team.

Ice hockey is another sport that has seen courageous returns to action after illness.

In December 2006, National Hockey League rookie Phil Kessel was diagnosed with testicular cancer at the age of 19 and underwent surgery. He missed only 11 professional games before returning to action, and was a member of the US silver medal-winning team at the 2010 Vancouver Winter Olympics.

Mario Lemieux, one of the sport's biggest ever names, was at the top of his game when diagnosed with Hodgkin's disease, a type of lymphoma, in 1993. 

Lemieux underwent 29 days of radiation therapy as treatment before resuming a stellar career with the Pittsburgh Penguins, and also led Canada to its first Olympic ice hockey gold for 50 years at the 2002 Salt Lake City Winter Games.

Lemieux is widely acknowledged to have been one of the greatest ice hockey players of all time. His trajectory of fame, illness and further success was matched by two sportsmen of similar status in cycling and football, respectively Lance Armstrong and Bobby Moore.

Armstrong may have had seven Tour de France titles stripped from him for doping offences, but nothing can take away the fact that - doped or not - he earned them all having recovered from testicular cancer that had spread to his abdomen, lungs and brain.

That devastating diagnosis had been received by the American in 1996. Thirty years earlier Moore had led the England football team to the pinnacle of all achievements, captaining them to victory in the World Cup final - a dramatic and extended 4-2 win over West Germany in which Moore played a masterly and crucial part.

It was not widely known until years later, but 18 months before lifting the Jules Rimet trophy at Wembley Moore, then aged 24, had required surgery for testicular cancer.

There are few obvious points of similarity between a young footballer born in the East London borough of Barking and a young female swimmer born in Tokyo. But they share, with certain others, enormous self-discipline and courage.

Speaking through her tears after qualification, Ikee said: "Even if you go through suffering and pain, your hard work will always be rewarded."