Lung cancer is the most common cancer worldwide, and causes over 1.37 million deaths every year. An optimistic survival rate for lung cancer depends on a prompt diagnosis while the cancer is still localized to the lungs, but because of the generality of symptoms, many diagnoses are made too late.
A group of researchers from the United Kingdom made a disturbing discovery on lung cancer’s ability to remain undetected for up to 20 years.
The study, which is now published in the journal Science, examined seven lung cancer patients who were either smokers, ex-smokers, or have never smoked. They sought to understand how one’s lung cancer genes evolved to cause different regions of the tumor to be genetically distinct. According to them, the most likely culprit behind these genetic aberrations is smoking.
Two out of seven subjects quit smoking 20 years prior to the study. Lead author Charles Swanton, a professor of cancer research at the London Research Institute, observed genome scarring from their former bad habit, which allowed the team to form a timeline of the tumor’s mutation. After smoking had caused genetic mutations and the subjects had quit, an enzyme called APOBEC, began driving more genetic faults.
Co-author and biometrician Nick McGranahan explained this enzyme’s known primary function is to drive viral mutation, but the findings suggest that cancer cells use it to their advantage. These constant and complex genetic mutations may be the reason why lung cancer is so difficult to treat.
Fellow scientist Elza De Bruin said that there is hope in lung cancer when a diagnosis is made early, before the tumor has managed to evolve drastically. Research efforts should also look into advancing early screening techniques, and explore the possibility of detecting signs of cancer in circulating tumor DNA in patients’ blood.