Toon Aerts announced on Tuesday that an out-of-competition doping control he submitted to ten days before the UCI Cyclo-cross World Championships came up positive for a banned substance. The UCI, however, did not issue a provisional suspension because the substance, a metabolite of the breast cancer drug Letrozole, while prohibited in- and out-of-competition is in a class called "specified substances" that do not require a mandatory provisional suspension.
Aerts voluntarily ended his season and was placed on inactive status by his team, Baloise-Trek, pending the analysis of the B-sample.
Letrozole is normally used to treat women with estrogen-dependent breast cancer. It is an aromatase inhibitor and acts by blocking the body's production of estrogen. There is no medical use for Letrozole in men, and is banned because it can be used to mask the effects of anabolic steroids or to promote higher testosterone levels by blocking that hormone's breakdown.
The drug is listed on WADA's prohibited substance in the half of "hormone and metabolic modulators" that are 'specified substances', ie. a substance that is potentially allowed, such as a hormone that is naturally produced in the body or a common food contaminant. The anti-doping rules of WADA and the UCI allow for reduced suspensions in the case of specified substances in contrast to anabolic steroids or EPO, which are banned at all times and require a minimum four-year suspension for positives.
Positives for a specified substance Letrozole typically require a two-year suspension, but can be reduced if athletes can establish the substance entered their bodies unintentionally, ie they did not intend to cheat.
The ban can be further reduced to between one year to no ban at all in either case by proving "No Significant Fault or Negligence", through a contaminated supplement, for instance.
Fellow cyclo-cross racer Denise Betsema escaped a positive for an anabolic steroid, which could have ended in a four-year ban, with an off-season, back-dated six-month suspension this way.
Italian tennis star Sara Errani tested positive for the same drug in 2017. She argued that her mother had contaminated the family's tortellini with the breast cancer drug and was initially given a two-month suspension. However, the Italian anti-doping agency took the case to the Court of Arbitration for Sport and extended her ban to 10 months.
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Laura Weislo has been with Cyclingnews since 2006 after making a switch from a career in science. As Managing Editor, she coordinates coverage for North American events and global news. As former elite-level road racer who dabbled in cyclo-cross and track, Laura has a passion for all three disciplines. When not working she likes to go camping and explore lesser traveled roads, paths and gravel tracks. Laura's specialises in covering doping, anti-doping, UCI governance and performing data analysis.