A massive new study that scientists are calling the most comprehensive global data analysis of non-smoking related lung cancer ever conducted has found that the number of non-smokers who are diagnosed with lung cancer has remained relatively stable since 1930.
Previous studies and concerns about rising pollution and environmental risk factors had fueled speculation that non-smokers today face a greater risk of developing lung cancer than non-smokers in the past. But the new study, funded by the American Cancer Society, reviewed data on over 2.4 million non-smoking lung cancer patients in North America, Europe, Asia, from 1960 to 2004 and found that the odds of a non-smoker developing lung cancer have remained constant over the last few decades. The study did find, however, that the odds of getting lung cancer were greater for non-smoking African Americans and Asians living in Asia.
“We’re talking about figures that are right up there with brain cancer in terms of the hard numbers of patients,” said Dr. Michael Thun, head of epidemiological research at the American Cancer Society. “And relative to other cancers, lung cancer research is under-funded. So, the value of this kind of broad effort to better understand the problem is immense.”
While little is known about what causes lung cancer in non-smokers, scientists suspect genetic pre-disposition combined with a variety of different environmental factors, like second hand smoke and asbestos, are the likely culprits. Scientific estimates put the proportion of lung cancer patients who are non-smokers at just ten to fifteen percent. That small percentage, however, still accounts for a startling number of deaths: 16,000 to 24,000 every year in the U.S. alone. If non-smoking related lung cancer were a separate category of cancer, it would be among the top ten cancer killers.
The review’s conclusion that African-Americans are at greater risk of developing non-smoking related lung cancer reaffirms the medical community’s need to adjust their methods of assessing cancer risk for patients depending on racial makeup. Researchers’ at the University of Texas recently developed the first lung cancer risk model for African Americans.
Previous risk cancer models were based on the studies of white adult patients. The model developed using that group was only 66 percent accurate when applied to African-Americans.
“The one size fits all risk prediction clearly does not work,” lead researcher Dr. Carol Etzel, of the UT M.D. Anderson Cancer Center, said in a written statement. The new model has been tested to be 79 percent accurate in predicting lung cancer. Etzel and her team are currently trying to develop a model for Hispanic adults.
Related: World Lung Foundation