Ross Hutchins revealed he may have had cancer for 18 months as he prepared to begin treatment for Hodgkin's Lymphoma.
The British Davis Cup player announced the news on Sunday and he will undergo his first chemotherapy session at the Royal Marsden Hospital on Thursday.
Hutchins said: "They've been absolutely brilliant. I feel very confident that they're going to do the best for me. I don't find it that scary, I'm ready for the treatment. The mentality I have is the sooner I begin the chemotherapy, the sooner I can get this out of my body and get back on court. The wait is the tough part. I want to fight this thing."
The illness revealed itself in the form of back pain, which Hutchins first felt during Britain's Davis Cup tie against Belgium last April. It went away for a few months but came back stronger in the autumn, and the 27-year-old flew home from the Lawn Tennis Association's training camp at La Manga in Spain last month for tests.
Initially Hutchins saw a kidney specialist, who gave him the all-clear but sent him to a chest specialist because tests showed he had pneumonia.
"She said I had enlarged lymph nodes in my chest close to my heart, which could mean my body was fighting an infection or I could have lymphoma," said Hutchins. "As soon as she said it I could kind of tell she felt it was more likely it was cancer.
"I had a biopsy and on December 27 I had the call that I had been diagnosed with Hodgkin's Lymphoma. Obviously that was tough, but I found it tougher to take the first time they mentioned what it might be and I realised it could be life-changing."
Hutchins revealed his diagnosis on Twitter and has been overwhelmed by the messages he has received, more than 1,000 from fellow players, cancer sufferers and from strangers simply wishing him well.
The most high-profile message of support came from Andy Murray, a long-time friend and occasional doubles partner of Hutchins.
An emotional Murray said after his title win in Brisbane on Sunday: "I'd like to dedicate this victory to one of my best friends. He's back home watching and you're going to get through it."