Lung cancer can lie dormant in the body for more than 20 years before suddenly turning aggressive, but that may turn out to be the disease's Achilles heel, new research suggests.

Its tendency to remain undetected for years might be turned against it, providing the opportunity for early detection through screening and the chance of timely preventative treatment, scientists say.

A study analyzing lung cancers patients including active smokers, non-smokers and former smokers found the original genetic errors that can lead to lung cancer might remain undetected for decades.

The cancer becomes aggressive only when additional new genetic errors occur in different parts of a tumor that evolve differently and become genetically unique, the researchers said.

That's why early efforts to identify lung cancer during its long dormancy are important, they said.

"If we can nip the disease in the bud and treat it before it has started travelling down different evolutionary routes we could make a real difference in helping more people survive the disease," says Nic Jones, chief scientist in the study done at Cancer Research UK in London.

In the study the researchers sequenced the genomes of multiple parts of tumors from cancer patients and managed to reconstruct their evolutionary tree.

Some mutations existed at the trunk of that tree, while others occurred later along the tree's leaves or branches, the researchers said.

The findings imply many genetic characteristics linked with cancer will be present a long time before they cause any symptoms, and should be considered targets for efforts in early detection of lung cancer, they said.

"The vast majority of lung cancers that I see are diagnosed late, once they have developed these multiple genetic differences that make them difficult to treat," study researcher Charles Swanton says. "So anything you can do to diagnose them early is going to make a big difference to the outcome."

One possibility that could lead to earlier detection might be a simple blood test the determine a person's genetic disposition toward lung cancer based on the new finding about the decades-long series of genetic mutations that can lead to it, Swanton says.

Survival rates in cases of lung cancer remain "devastatingly low" as even new, targeted treatments have had only limited impacts on the disease, he notes.

"By understanding how it develops we've opened up the disease's evolutionary rule book in the hope that we can start to predict its next steps," he says.