Italian rider Ivan Basso is quitting the Tour de France after revealing he has testicular cancer.

The two-time former Giro d’Italia winner was due to be a key support rider for one of the favourites Alberto Contador in the mountain stages beginning on Tuesday.

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But instead the 37-year-old – who has previously served a two year doping ban – on Monday said he is heading back to Italy for treatment.

“Unfortunately I have a bad announcement to give to you guys,” Basso said at the Tinkoff-Saxo team’s hotel in Pau on Monday’s Tour rest day.

“In stage number five I had a really small crash and on the crash I touched my testicle on the saddle.

“For a few days I felt a small pain. (On Sunday) our doctor spoke with the doctor of the Tour and we decided to go to make a special analysis to the hospital.

“The examination gave me bad news: I have a small cancer in the left testicle.

“So it’s easy to understand that I have to stop and go back to Italy. Our doctor is already in contact with the specialist in Italy to fix the operation as soon as possible.

“I can’t say to you more details because we discovered this two hours ago, so that’s all.

“I have to leave but I want to give my support to our captain (Contador) to be in yellow in Paris and want to say thanks to my team for their support in this situation and the whole Tour organisation and medical staff.”

An emotional Contador said the news had been hard to take both for him personally and the rest of the team.

“It has been a very tough day for the whole team; we never imagined something like that,” he said.

“Now the first thing is to analyse what’s happened to Ivan, to support him and hope that everything’s resolved as soon as possible.

“We want to give Ivan the support of the whole team and you can be sure we will fight for the yellow jersey to bring him yellow in Paris.

“For me it has been very hard because over the last 180 days we spent 120 days together and we have been very close to each other. But I’m sure that we will be together again in Paris to celebrate the Tour victory.”