Five-time Olympic champion swimmer Nathan Adrian said he has testicular cancer but is confident of recovery and wants to compete at the 2020 Tokyo games. In a statement on Twitter on Thursday, the 30-year-old 2012 100m freestyle gold medallist said he expects to be back swimming within "weeks" after starting treatment. Adrian, who also has four Olympic gold medals as a member of US relay teams, said his illness had been diagnosed early. "We caught it early, I have already started treatment and the prognosis is good," Adrian wrote. Read | Thackeray movie: Celebrations in Mumbai as Nawazuddin Siddiqui-starrer hits silver screen "I will be back in the water in a few short weeks with my sights fully set on Tokyo." Adrian has appeared in three Olympics, in 2008, 2012 and 2016, winning eight medals in total. He has also won 11 world championship medals throughout his career. Adrian meanwhile used news of his illness to encourage men to seek regular check-ups for their health. "I've realized that too often we tend to avoid these important topics, ignore potential warning signs, and put off getting medical help we need," Adrian wrote. "I am keeping a positive attitude as cases such as mine are curable."