LONDON - Former Wales striker John Hartson has been diagnosed with brain cancer, a hospital statement said on Monday. Hartson, 34, who played 51 times for Wales and for clubs including Arsenal, West Ham United, Coventry City, Wimbledon, Luton Town and Celtic, is facing many months of treatment. "Mr Hartson attended Singleton Hospital on Friday (July 10) displaying symptoms consistent with testicular cancer," Gianfilippo Bertelli, a consultant medical oncologist, said in the statement from the Swansea hospital. "A number of clinical tests were put in place and these have confirmed the presence of testicular cancer. Unfortunately, it has also been confirmed that this cancer has spread to Mr Hartson's brain. "We will be commencing a course of radiotherapy and chemotherapy as soon as possible and foresee many months of treatment." His former club Celtic issued a statement of support on their website, saying: "It is very difficult for us to understand what John is going through at the moment but we will offer any support we can to a great Celtic player." Hartson joined the club in 2001 for 6 million pounds and spent five years there, scoring 89 goals. He retired in February 2008.