More than 170,000 people in the UK who were diagnosed with cancer up to 40 years ago are still alive, a report by Macmillan Cancer Support has suggested.
People are twice as likely to survive for at least a decade after being diagnosed than they were at the start of the 1970s, the charity said.
It said better treatments and speedier diagnoses are among the reasons.
But cancer can leave a legacy of side effects such as depression and financial difficulties, it also warned.
The report, called Cancer Then and Now, estimates around a quarter of survivors will have long-term issues that need support.
Helen Taskiran told BBC News she suffered from depression as a result of surviving cancer, and has even missed out on job opportunities because of it.
She was first diagnosed in 1991 with bowel cancer, which she survived, but since then has been diagnosed with four other cancers, including breast, skin and womb.
“They’ve left me with swollen arms and legs, tiredness, sometimes depression, [making me] dubious about going for other jobs,” said Helen, whose son was just three years old when she was first diagnosed.
“Your self-esteem goes down, you’re wondering whether people will judge you.
“I’ve had job interviews where people have turned me down because I’ve had cancer – so that all adds to the depression. I’ve been offered jobs and then when I’ve filled in medical forms all of a sudden the job has disappeared before it’s even started,” she added.
A total of 625,000 people in the UK are currently suffering with depression after cancer treatment, Macmillan Cancer Support said.
‘I felt guilty at myself’
Greig Trout survived cancer at the age of seven, and again at 30, but he says the worst part of his battle was after his second all-clear.
He says he became “gripped by anxiety, and the fear of cancer coming back, or the fear that maybe it hadn’t gone”.
“I felt guilty, angry at myself,” says Mr Trout, now 37 and from Thames Ditton in south-west London.
“At times I was thinking ‘am I ungrateful for feeling this way after having survived when so many others don’t?’.”
Prof Jane Maher, chief medical officer at Macmillan Cancer Support, said: “We now see fewer of the big side-effects, such as an increased risk of heart attack and stroke, we saw after treatment in the 1970s and 80s.
“But some of the effects doctors consider ‘small’, such as fatigue and poor bowel control, can have a profound impact on someone’s quality of life.
“Sadly there is no cancer treatment available at the moment that does not carry a risk of side-effects.”
The charity said although a growing number of people are surviving long-term with cancer, more needed to be done to make sure they got the right care.
The organisation says it has evolved from being a handful of nurses providing end-of-life care in the 1970s to a much bigger network that even includes benefits advisers.
Health Secretary Jeremy Hunt said the fact more people were surviving cancer was “excellent news” and credited the work of NHS staff carrying out diagnosis, treatment and care to help patients.
“To help, we announced last year that by 2020 people diagnosed with cancer in England will benefit from an individually tailored recovery package,” he said.
Meanwhile the Welsh government said it welcomed the improvements, but a spokeswoman said “the numbers of people experiencing cancer in their lifetime are increasing and this is set against a backdrop of increasing pressures on NHS resources”.
Nell Barrie, of Cancer Research UK, also stressed it was important to continue focusing on “world-leading science to improve prevention, diagnosis and treatment, especially for the harder-to-treat cancers like lung, brain and pancreatic cancer”.