A cancer survival gap is growing between people living in the most and least deprived parts of Scotland, a charity has warned.
Analysis of survival rates for six common cancers found wide variations depending on where patients lived.
Macmillan Cancer Support said there needed to be a major step-up in cancer screening in deprived areas.
The Scottish government said it recognised the need to tackle such variations.
The charity used data from the Information Services Division, part of NHS Scotland which specialises in health statistics.
The analysis examined the survival rate of patients diagnosed between 2004 and 2008 and followed them for five years up to 2013, to reveal the increased risk of death for patients living in deprived areas, compared with affluent areas:
- Prostate cancer - 98%
- Breast cancer - 89%,
- Head and neck cancer - 61%
- Colorectal patients - 45%
- Liver cancer - 28%
Lung cancer patients faced poor outcomes regardless of their socioeconomic status, the charity found.
The study found lower rates of screening uptake and lower rates of treatment in deprived communities, while surgery was found to have had the most influence on survival.
This suggested those from deprived communities were less likely to receive surgery, possibly because of having more advanced cancer or poorer overall health, the charity said.
Janice Preston, head of Macmillan in Scotland, said: "It's completely unacceptable that someone's chances of surviving cancer could be predicted by their postcode.
"This new research gives us an up-to-date and in-depth understanding of the scale of the cancer survival gap in Scotland.
"It also provides the most comprehensive ever look at the reasons behind it. While the sheer number of factors that impact on survival means there is no magic bullet to solving this problem, this research points to clear areas for improvements, including encouraging earlier diagnosis and the take-up of screening in deprived areas."
Professor Jason Leitch, the Scottish government's national clinical director, told BBC Radio Scotland that he was "not surprised" by the data.
Speaking on Good Morning Scotland, he said people in more deprived areas were less likely to have their cancers detected early. Some would not go to routine screenings while others ignored the symptoms of illness, he added.
The former dentist and oral surgeon said: "I used to see patients with years of ulcers, people who would come in two years after their first symptom. And their cancer would be very advanced.
"Then I would see other people who would come within three weeks of seeing something that was a little bit unexplained and we could always treat that individual quickly and do very well.
"The same thing applies to bowel cancer, to prostate cancer, to lung cancer. So early diagnosis is the key."
Professor Leitch said that, historically, men in industrial areas like Glasgow and Lanarkshire, were reluctant to go to their GP.
But he pointed to the recent success of the Detect Cancer Early programme, which has recruited celebrities including Sir Alex Ferguson and Elaine C Smith to front awareness campaigns.
He added: "There is no question that poverty is one of the contributory factors to early cancer death. And the health service and the social care service is only part of that solution.
"We need solutions around employment, around housing, around education and around criminal justice. So all of that together is how government needs to tackle early cancer death."
Labour's health spokesman Anas Sarwar described the charity's report as "grim and deeply concerning".
He said: "We already know that a person is less likely to get diagnosed and less likely to survive cancer if they come from a poorer background.
"In Scotland, we are seeing the health inequality gap widen not narrow under the SNP government.
"This follows on from official figures which showed that cancer screening rates are going backwards in the poorest communities too."
A spokesman for the Scottish government said that cancer mortality rates had fallen by 11% over the past 10 years but that it recognised the need to tackle variations between least and most deprived communities.
He added: "This is why our cancer strategy, backed by £100m of additional investment, sets out clear actions aimed at reducing health inequalities.
"We're already seeing results, with increased screening participation and earlier diagnosis, however there's much more still to be done.
"Health inequality is closely linked to income inequality, which is why we have made tackling poverty as a priority."