Lung cancer is the most common cause of cancer-related death in men and women worldwide. In the U.S., lung cancer caused 1.6 million deaths in 2012.

Over 40,000 people are diagnosed with lung cancer every year. The survival rate is less than a 10 percent at least five years after diagnosis. 

Like Us on Facebook

Two-thirds of lung cancer patients suffer from an advanced forms of the disease, by which tim treatments are less likely to be effective.

Why is lung cancer so pervasively fatal?

Researchers in the United Kingdom have finally found out why. They've discovered lung cancer can remain dormant for up to 20 years before being detected. In that time, lung cancers also keep mutating thereby becoming more difficult to cure.

The initial genetic fault that triggers the mutation is often caused by smoking. Researchers found that as lung cancer genes mutate and adapt, they cause different parts of a single tumor to become genetically unique after this initial genetic fault.

This awakens the dormant lung cancer cells and causes new, additional genetic mistakes to occur. This then triggers rapid cancer growth.

The huge variety of genetic errors within lung cancers explains why targeted treatments have had limited success against the killer disease.

"The problem with lung cancer is we often diagnose patients too late," said Charles Swanton, a professor of cancer research at the London Research Institute and author of the study recently published in the journal, Science.

"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," Swanton added.

He noted that the more diverse a tumor, the more high-risk it's likely to be.

Researchers revealed that smoking causes many of the early genetic faults linked to lung cancer. Most of the new cancer-causing mutations are the results of a process controlled by a protein called APOBEC.

APOBEC's basic function is to mutate viruses, but lung cancer cells apparently hijack APOBEC to hasten their reproduction.

This research highlights the need to find better ways to detect lung cancer earlier when it's still following just one evolutionary path.

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