Vital opportunities to diagnose cancer patients in England earlier and increase their survival chances are being missed, experts are warning.

Cancer Research UK found "unacceptable variation" between different areas after reviewing cases in 2012 and 2013.

It said if all areas were as good as the best, 20,000 cases could have been spotted sooner across the country.

The worst area for late diagnosis was Merseyside, where half of cancers were found at a late stage.

This compared to the area incorporating Bath, Gloucestershire, Swindon and Wiltshire, where 40% were diagnosed late.

If that gap was closed, another 1,000 patients in Merseyside could have had their cancer diagnosed earlier.

Easier to spot

Devon, Cornwall and the Isles of Scilly were found to have the second best rates of early diagnosis out of the 25 areas in England, with 43% found late.

At the other end of the scale, Greater Manchester and Durham, Darlington and Tees performed only slightly better than Merseyside.

The worst areas for early diagnosis Region Percentage of late stage diagnoses Merseyside 49% Greater Manchester 48% Durham, Darlington and Tees 48%

Earlier diagnosis can make a significant difference to survival.

For the eight most common cancers being diagnosed at stage one or two - classed as early diagnosis - means an individual has an 80% chance of surviving at least 10 years compared to 25% when the cancer is found at stages three or four.

CRUK, which used official data from Public Health England, to carry out its analysis, said it was unclear exactly why the variation was found.

One factor is likely to be differences in the types of cancer being diagnosed - some are easier to spot earlier than others.

But the charity said there were likely to be other factors at play that were easier to tackle.

Diagnostic tests

CRUK's Dr Jodie Moffat said: "These might include patients not going to their doctor as early as they could with possible cancer symptoms, and GPs sometimes failing to suspect cancer or not referring patients for diagnostic tests promptly."

CRUK will be launching an early diagnosis campaign next week to encourage people to keep an eye on their bodies.

The best areas for early diagnosis Region Percentage of late stage diagnoses Bath, Gloucestershire, Swindon and Wiltshire 40% Devon, Cornwall and Isles of Scilly 43% East Anglia 44%

Early diagnosis was one of the key themes of NHS England's cancer strategy that was launched in the summer.

It pledged to create a target for diagnosis - four weeks from urgent referral from a GP - to help save lives.

A key element of this was increasingly the ability of GPs to order cancer tests directly themselves - instead of having to go through a hospital consultant.

Maureen Baker, of the Royal College of GPs, said this would make a difference, but said GPs were still doing a good job.

She added: "Where our patients live should not be a factor in their health outcomes."

Sean Duffy, NHS England's national clinical director for cancer, said the health service was working together to "deliver" on what was promised in the strategy.

Information for what stage a cancer is diagnosed at is only available for about two thirds of the 280,000 new cases a year. The 20,000 figure quoted by CRUK is based on these cases.