A survey of young people with cancer found that six in 10 believed they could have been diagnosed earlier.
The Teenage Cancer Trust questioned 400 young cancer patients, of which 60 per cent felt they could have been diagnosed quicker.
Twenty-five per cent of patients also revealed they had to pay at least four visits to their GP before their symptoms were dealt with seriously.
Every year, 2,100 people aged between 13 and 24 in the UK are diagnosed with cancer.
While young people only represent 0.6 per cent of the overall number of cancer sufferers in Britain, campaigners have urged for them not to be overlooked.
Susie Rice, who works for Teenage Cancer Trust, told BBC Radio 1: “Young people are experts at their own bodies. If there is something wrong with them, if they think there’s a lump or a swelling, they must speak to their GP.
“And the job for the GP is to listen to these people and take them seriously,” she added.
The Department of Health told Radio 1: “The government is determined to improve cancer survival rates and early diagnosis is the key.
“Our cancer strategy sets out the direction for improved cancer care, aiming to save an additional five thousand lives a year.”