Individuals who have evidence of pulmonary scarring on a chest X-ray are at an increased risk for developing lung cancer, according to the results of a study published in the November 24, 2008 issue of the Archives of Internal Medicine.
Lung cancer is the most common cancer in the world and is the leading cause of cancer death, with 160,000 deaths in the United States annually. Each year lung cancer kills more people than breast cancer, colon cancer, and prostate cancer combined. Lung cancer is primarily associated with environmental factors such as smoking and other carcinogens. There has been much debate regarding screening for lung cancer because no screening procedure has proven to decrease the number of lung cancer deaths. Historically, chest X-rays have been used as a preliminary method to detect lung cancer.
Because fibrotic scars are often found in proximity to lung cancer when it is diagnosed, researchers have speculated that there might be a relationship between scarring and the subsequent development of lung cancer. In order to examine this, researchers evaluated data from 66,863 patients involved in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The patients were aged 55-74 and were cancer-free upon initiation of the trial. Patients underwent a baseline screening chest X-ray and were then followed for up to 12 years.
Scarring was present in 5,041 patients, or 7.5% of all baseline X-rays. Individuals with scarring had a 50% increased incidence of lung cancer in the same lung compared with individuals with no scarring. However, there was no increased risk in the opposite lung. This elevated risk persisted throughout the entire follow-up period.
The researchers concluded that pulmonary scarring is associated with an increased risk of lung cancer and even speculated that “localized inflammatory processes associated with scarring promote the subsequent development of lung cancer.” Research will likely be ongoing to examine the relationship between pulmonary scarring and lung cancer. In addition, the results of this study may help to validate the use of screening chest X-rays in certain high-risk individuals.
 Yu YY, Pinsky PF, Caporaso NE, et al. Lung cancer risk following detection of pulmonary scarring by chest radiography in the prostate, lung, colorectal and ovarian cancer screening trial. Archives of Internal Medicine. 2008; 168: 2326-2332.
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