Seven risk factors, including two new ones, can help predict susceptibility to developing lung cancer and they don’t just apply to heavy smokers.
A new joint study from Norway and Greece has been able to find that younger people who haven’t smoked as much may also be at risk of developing lung cancer.
The HUNT study in Norway used a survey of 65,000 Norwegians between the ages of 20 and 100, following them for 16 years, which helped identify the strongest risk factors.
Right combination of risk factors
Oluf Dimitri Røe, senior oncologist at the Department of Oncology at Levanger Hospital in Trøndelag county, Norway, decided to use data from the large HUNT study to find the right combination of risk factors that could predict lung cancer with high accuracy.
The Nord-Trøndelag Health Study collected large quantities of health data, containing information on nearly 120,000 people.
What the data revealed
Following three years of work, the research group found that 94% of patients diagnosed with lung cancer were smokers or ex-smokers. There were no clear risk factors found in the 6% who had not smoked.
It was also found that 21% of lung cancer cases occurred in people under 55 years of age, while 36% of the cases were people who smoked fewer than 20 cigarettes a day for less than 20 years.
What are the risk factors?
The research group was able to pinpoint individuals among smokers and ex-smokers more likely to develop the disease. From 16 variables, there are seven identified risk factors, two of which are new.
A risk calculator was set up by the researchers which could help calculate personal risk of developing lung cancer within six and 16 years.
The five well-known contributing risk factors are:
- Increasing age;
- Pack-years (based on how many years you’ve smoked 20 cigarettes daily);
- How many cigarettes you’ve smoked daily (a few cigarettes a day for many years is more harmful than many cigarettes for a few years);
- How long it’s been since you quit smoking (the risk drops over time); and
- Body mass index (BMI; the lower your BMI the higher the risk).
Two new factors added are:
- Periodic daily cough (increases risk); and
- How many hours a day you’re exposed to smoke indoors (increases risk).
By using these seven risk factors, researchers wanted to see if they could predict the disease in 45,000 individuals.
Predicting lung cancer
When people were paired up, the group was able to predict with nearly 88% accuracy who would develop lung cancer first.
Using the model, only 22% of smokers and ex-smokers would need a CT scan to identify up to 85% of those who would develop lung cancer within the next six years.
Røe said: “The method can reduce the number of people exposed to radiation from unnecessary CT scans and maximise identification of persons with true risk.”