The NHS is unlikely to be able to afford the next generation of cancer treatment and patients will be forced to seek private treatment, cancer specialists have warned.
A BBC survey found that many doctors are worried about the situation, as only those drugs deemed to be cost-effective are approved for NHS use by the National Institute for Health and Clinical Excellence (Nice).
As drugs become more advanced, the cost of treatments is rising, and some such as the lung cancer drug Tarceva have not been approved.
Cancer specialists told the BBC that some patients who are prepared to pay for cancer drugs are being told that they will have to pay for their entire cancer care to prevent a two-tier system within the NHS.
Professor Nick James, a cancer specialist from Birmingham, told the Today programme that being denied drugs on the NHS was "almost worse than if the drugs didn't exist".
"That's very distressing for the patients, it's very distressing for the clinicians who have to discuss the implications of this for patients," he said.
"They know they could buy them if they were rich enough, but most patients are not rich enough to do so and that's a very distressing set of circumstances."
A new report by the government's cancer tsar, Professor Mike Richards, has also warned that, despite recent improvements in the nation's cancer care, further reforms will be necessary if patient care is to progress.