Scientists have discovered pancreatic cancer is four separate diseases, paving the way for more accurate diagnosis and treatment.
Researchers said the findings were the "launch pad" to investigate new treatments because doctors currently have little insight into which will be most effective for patients.
Around 8,800 people are diagnosed with pancreatic cancer in the UK each year and just 20% of adults survive more than a year after being diagnosed.
Less than 5% of sufferers survive after five years and only 1% are still alive after 10 years.
The study, carried out by a team of researchers at the University of Glasgow, looked at 456 pancreatic cancer tumours and found the disease could be classified as one of four different sub-types; squamous, pancreatic progenitor, immunogenic and ADEX.
Professor Sean Grimmond, who led the study, said there were already cancer drugs available or in development that could target parts of the "damaged machinery" which led to pancreatic cancers.
For example, some strains of the disease were associated with mutations normally linked to colon cancer or leukaemia for which experimental drugs are being used to treat, he said.
Prof Grimmond said: "This study demonstrates that pancreatic cancer is better considered as four separate diseases, with different survival rates, treatments and underlying genetics.
"Knowing which sub-type a patient has would allow a doctor to provide a more accurate prognosis and treatment recommendations.
Dr Peter Bailey, an author of the study, added: "The standard of care for pancreatic cancer really hasn't changed in the last 20 years. There are a number of different chemotherapeutic options but in general it's not very selective – it's like hitting the disease with a mallet with your eyes closed."
The charity Pancreatic Cancer UK described the results, published in the journal Nature, as "incredibly exciting".
Its head of research Leanne Reynolds said the findings meant that in the future "the right patients can be given the right treatment at the right time".
She said: "This is crucial for people with pancreatic cancer, because the disease is difficult to diagnose, is often diagnosed terribly late, and just four per cent of people live for five years or more after diagnosis.
"If we can predict more accurately which treatment would be most effective for each patient, we can ensure patients have the best chance of living for as long as possible, as well as possible.
Dr Emma Smith, from Cancer Research UK, said: "Identifying different types of pancreatic cancer and revealing the disease's complexity is an important step towards finding more effective treatments.
"This will help to ensure patients are given the therapies that are most likely to help. Improving survival for people with pancreatic cancer is one of our top priorities, and we urgently need more research like this if we're going to beat this disease in the future."