Cyclist Ivan Basso announced yesterday that he has testicular cancer and is withdrawing from the Tour de France. Basso, 37, is returning home to Italy for treatment.

According to BBC News, the cancer was discovered after Basso, who has finished in the Tour de France's top 10, complained of pain following a crash.

Basso's diagnosis follows that of Lance Armstrong, who was diagnosed with testicular cancer at the age of 25. Armstrong successfully battled the disease and returned to win seven consecutive Tour de France titles. Later, he was accused of doping and stripped of his titles.

Like Armstrong, Basso admitted to doping and was banned from competitive cycling for two years.

The diagnosis of two top cyclists revives the question of whether cycling, which causes a man to sit on the bike for hours, increases his risk of testicular cancer. Although a 2014 British study at University College London found that while men who cycle more than nine hours a week have no increase in erectile dysfunction and infertility, it found they are six times more likely to be diagnosed with prostate cancer.

Doctors, however, say the most likely reason is they are young. "The main common denominator is their age," Dr. Thomas Schwaab, an associate professor of oncology at Roswell Park Cancer Institute in Buffalo, New York, told Fox News.

"There's no link between athletic sports in general and biking in particular with regard to the incidence of testicular cancer," he said, adding that the cancer has a very good prognosis if caught early.

Armstrong offered Basso support in a tweet: "Wishing him the very best as he embarks on his cancer journey."