Older lung cancer patients are being denied life-saving surgery, a charity has said.
Those aged 75 or over who are otherwise in good health and whose cancer has not spread are five times less likely to be given life-extending surgery than younger patients, Macmillan Cancer Support said.
England and Wales have the worst five-year lung cancer survival rates in Europe among the over 75s, a spokesman said.
The UK carries out less lung cancer surgery on older people than in other European countries, he added.
In some instances patients are assessed for treatment based on age alone and not overall fitness, the charity said.
"I just cannot comprehend why healthy older lung cancer patients are given less life-saving surgery than younger patients, despite the fact that many could survive for years afterwards," said Ciaran Devane, chief executive at Macmillan Cancer Support.
"It is deeply sad that our survival rates in this age group continue to lag behind Europe. We should not send the message to older cancer patients that it is okay to discriminate.
"If we don't take heed of these figures now, things will get worse. The UK should match the best in Europe, not the worst.
"The NHS must ensure every older patient is treated based on their overall fitness, not their chronological age."
In the run-up to the general election next year, the charity is calling on all major political parties to commit to improving cancer survival rates.
"Otherwise we face another five-year government term of older cancer patients being let down, their lives undervalued and put at risk," Mr Devane added.
A Department of Health spokesman said: " It is shocking and wrong to deny people treatment because of their age, which is why we made it illegal in 2012. We want to lead the world in terms of cancer and, as recent figures show, there have been significant improvements in some cancer survival rates.
"However, lung cancer is the UK's biggest cancer killer and we are taking action. Our Be Clear on Cancer campaigns are helping to raise awareness, leading to more cancers being diagnosed, many at an earlier stage.
"We are investing £750 million over four years to tackle cancer so patients have the best chances of being diagnosed earlier and getting the best treatment and care available."