Cyclocross star Toon Aerts tests positive for banned substance

The 28-year-old said he doesn't know how a metabolite of a breast cancer medication got into his system.

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Belgian cyclocross racer Toon Aerts (Baloise Trek Lions) has tested positive for the banned substance letrozole.

Aerts, 28, winner of four CX races this season, announced via his Baloise Trek Lions team that he had received notification from the UCI of a positive test from earlier in the season.

“Yesterday my world was turned upside down,” Aerts wrote. “I got a letter from the UCI that no athlete wants to get in his career. I received a message that an abnormal result was found in my urine sample that was taken at an out-of-competition check with me on January 19.

“I am currently in the dark as to how this could have happened. The product letrozole metabolite was found in my urine sample. A product I had never heard of until yesterday and I don’t know how it got into my body.”

Letrozole is a prescription medication used to fight breast cancer. As described by USADA, “by decreasing the amount of estrogen in the body, letrozole can slow or stop the growth of some types of breast cancer cells that need estrogen to grow.”

Letrozole can also be used as a performance-enhancer. To quote USADA: “Athletes who abuse anabolic steroids might use an aromatase inhibitor like letrozole to prevent the formation of estrogens, and therefore reduce or prevent the unwanted and feminizing effects of anabolic steroid use.”

WADA bans the use of letrozole both in and out of competition. According to USADA, “letrozole is a powerful drug that cannot be legally included and/or marketed as an ingredient in dietary supplements”.

Aerts has said that he won’t race until the case is resolved.

“At the moment my mind is not on races and I have decided in consultation with the team to end my season until there is more clarity in this matter,” he wrote. “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.”

Aerts’s team added that it “take(s) him at his word that he himself has not taken any products that may contain the substance.” The team also explained that it has a strong anti-doping policy.

“We have a strict zero tolerance within Baloise Trek Lions for all our riders. As a team, we owe this to ourselves, the other riders in the team and the cycling fans.

“The team will refrain from further comment as long as the result of the B-sample is not known.”

In 2017, Italian tennis player Sara Errani tested positive for letrozole and received a two-month ban. Errani blamed contamination from her mother’s breast cancer medication for the positive test.

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