Around two out of every three people diagnosed with lung cancer are 65 or older, but according to new evidence, they may show signs before the age of 50. A recent study funded by Cancer Research UK and the Rosetrees Trust has revealed that genetic factors leading to the development of lung cancer can stay dormant in a patient for up to 20 years before the disease turns aggressive.

"Survival from lung cancer remains devastatingly low with many new targeted treatments making a limited impact on the disease. 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," Professor Charles Swanton, from Cancer Research UK's London Research Institute and the UCL Cancer Institute, said in a statement.

Swanton and his colleagues determined genetic mistakes that caused lung cancer in smokers, ex-smokers, and people who have never smoked. These genetic faults were not detected for a number of years before being triggered by more faults later in life, which led to the disease’s progression. As the disease progresses, different surges of genetic faults appear in different areas of the tumor, causing each section to progress down a different path. The research team concluded that each part of the tumor was genetically unique.

Findings also showed that early genetic faults were the result of smoking’s role in the development of lung cancer. However, as the disease progressed these earlier faults became less important, seeing as the new faults became responsible for generating mutations in the tumor that are controlled by the protein APOBEC. Researchers hope that by revealing lung cancer can lie dormant for many years, cancer experts can begin developing better early detection methods.

"This fascinating research highlights the need to find better ways to detect lung cancer earlier when it's still following just one evolutionary path,” said Professor Nic Jones, Cancer Research UK's chief scientist. “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.”

According to the American Cancer Society, an estimated 224,210 new cases of lung cancer in the United States are expected for 2014, in addition to 159,260 deaths. Lung cancer accounts for 13 percent of all new cancer diagnoses, making the second most common cancer behind prostate cancer in men and breast cancer in women. Less than 10 percent of lung cancer patients survive five years after their diagnosis. Revealing the variety of faults within lung cancer may explain why targeted treatments are unsuccessful. Treating a specific area of the tumor is only successful in that area while leaving other parts of the tumor to progress.

"Building on this work Cancer Research UK is funding a study called TRACERx which is studying 100s of patient's lung cancers as they evolve over time to find out exactly how lung cancers mutate, adapt and become resistant to treatments," Jones added.

Source: Mitter R, McGranahan N, Bruin, E. et al. Spatial and temporal diversity in genomic instability processes defines lung cancer evolution. Science. 2014.