Belgian cyclocross star Toon Aerts tests positive for banned drug but protests innocence

Breast cancer drug Letrozole found in out-of-competition test from before World Championships

Toon Aerts
(Image credit: Getty Images)

Belgian cyclocross start Toon Aerts (opens in new tab) has said that he will do "everything" to prove his innocence after an out-of-competition doping control sample from January 19 was found to contain a banned substance.

The breast cancer drug Letrozole turned up in his submitted “A” sample from 10 days before the World Championships. Should his "B" sample also be positive, he will lose his sixth-place finish from the Worlds, along with a few other cyclocross results.

In a statement released on Tuesday night, Baloise-Trek Lions rider Aerts said: "I will do everything I can to prove my innocence and clear my name."

The Belgian has twice won the cyclocross World Cup and has finished third at the Worlds on three occasions.

Letrozole is an aromatase inhibitor that is used mainly to block estrogen and slow the progression of breast cancer, the NHS says it "can also help prevent breast cancer coming back". However, it is also used by people taking anabolic steroids who want to block estrogen's feminising effects, and is therefore on WADA's banned list.

"Yesterday my world was turned upside down," Aerts said. "I received a letter from the UCI that no athlete wants to receive in his career. I was informed that an abnormal result was found in my urine sample, which was taken during an out-of-competition check at my home on January 19th.

"I am currently in the dark as to how this could have come about. The product 'Letrozole Metabolite' was found in my urine sample. A product that I had never heard of until yesterday and do not know how it got into my body."

The statement continued: "Anyone who knows me a little knows that I have been against any form of doping all my career and have always done everything I can to set an example as an athlete.

"I will therefore do everything I can to prove my innocence and clear my name. Pending the analysis of the B sample and further investigations, I will not comment. I would urge everyone to respect this and to give me and my family the time and opportunity to get more clarity first."

His team said that he will be stood down until more is known on the situation, which effectively means ending his season.

"We have given Toon a warm heart for years and we hope for soon and better news with him," the statement said. "As a precaution and in consultation with Toon, it has been decided that he will no longer take action and that he will be inactive until more is known," the team wrote.

"Within Baloise Trek Lions, we have a strict zero-tolerance for doping for all our riders. As a team, we owe that to ourselves, the other riders in the team and the cycling fans."

On Wednesday afternoon, the UCI confirmed the Adverse Analytical Finding for Letrozole Metabolite, and that the rider has the right to request and attend the analysis of his B sample. As the drug is a Specified Substance according to WADA, there is no mandatory provisional suspension. 

The statement reads: "In cases where there is no mandatory provisional suspension, the UCI publicly discloses Anti-Doping Rule Violations only at the end of the proceedings, unless the existence of the AAF is made public by another party before a decision is rendered, as it is the case now."

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Hello, I'm Cycling Weekly's senior news and features writer. I love road racing first and foremost, but my interests spread beyond that. I like sticking to the tarmac on my own bike, however.


Before joining the team here I wrote for Procycling for almost two years, interviewing riders and writing about racing.


Prior to covering the sport of cycling, I wrote about ecclesiastical matters for the Church Times and politics for Business Insider. I have degrees in history and journalism.