Most people associate asbestos exposure only to mesothelioma. However, asbestos exposure in conjunction with smoking is much more likely to cause lung cancer than mesothelioma. In other words, individuals who have been exposed to asbestos are statistically more likely to develop a lung cancer rather than mesothelioma.
Overall, lung cancer is much more common than mesothelioma. In fact, lung cancer is the leading cause of cancer deaths in the United States. Lung cancer kills more men in this country than any other cancer. Lung cancer kills more women than breast, ovarian and cervical cancers combined.
Jacques Fontaine, M.D., is the leading thoracic surgeon in the Mesothelioma Research and Treatment Program at the H. Lee Moffitt Cancer Center in Tampa. He will be writing regular blog posts for MesoCare.org, sharing his thoughts, ideas and experiences dealing with mesothelioma cancer. More information on Dr. Jacques P. Fontaine, MD
The purpose of a screening test is to identify the presence of a cancer in an individual before they begin to develop symptoms so that any treatments would have a better chance of improving survival (cure rates). Therefore, early detection (screening) is key to diagnosing the lung cancers at an early stage when the chances of a cure are much higher.
Screening programs for breast cancer with mammography, for colon cancer with colonoscopy, for cervical cancer with Pap smears, and for prostate cancer with PSA levels have already been in place for several years. However, until recently, there were no screening programs for lung cancer which is responsible for more deaths than all these other cancers.
For several decades, strategies to reduce lung cancer related deaths through screening have been evaluated, with the focus on regular chest x-rays and sputum cytology (analysis of mucus). However, these screening tools were not effective.
About 10 years ago, it was observed that CT scans may be more efficacious in screening than chest x-rays. CT Scans are much more precise and can pick up much smaller lung nodules (spots on the lungs) as compared to regular chest X-rays. In 2002, the National Cancer Institute initiated the National Lung Screening Trial (NLST).
This large, multi-institutional clinical trial that screened over 30 000 high-risk individuals with CT scan showed it was an effective program. This reputable study was recently published in the New England Journal of Medicine and has had much press around the world including several articles in the NY Times and Wall Street Journal.
The study confirmed that high-risk individuals with no symptoms who had a screening CT Scan were more likely to be cured from their lung cancers as most of their cancers were detected in very early stages. The individuals who underwent the CT Scan screening had a 20% reduction in mortality.
Although it would be ideal if all individuals could be screened, it is neither realistic nor advantageous to do so. The question arises, which groups should be screened for lung cancer? As was mentioned earlier, lung cancer has been closely related to smoking. Asbestos exposure is also an important risk factor. So it would only be logical to consider screening those persons who are at the highest risk of developing this type of cancer: Men and women over the age of 55 who have smoked for more than 20 years.
Although CT Scan screening catches the lung cancers earlier, thus leading to higher cure rates, there are some controversies (disadvantages) regarding screening programs. CT Scans are so precise that they catch a large number of lung nodules which may lead to further testing and increased medical expenses.
Most lung nodules detected on CT Scans are tiny in size and do not require any further testing or biopsies. In fact, over 90% of nodules detected on CT Scans turn out to be benign. So not every nodule needs to be biopsied as we would end up performing many unnecessary biospies. Therefore, individuals must be evaluated by experienced doctors to avoid unnecessary biopsies or further testing. Also, although the risk from radiation from CT Scans is present, it is very low if the screening scans are performed in experienced institutions.
In conclusion, men and women with a significant smoking history and asbestos exposure are at much higher risk of developing lung cancer. These individuals would benefit from enrolling in a CT Scan screening program even if they have no symptoms. Screening would allow earlier detection of the cancers when the cancers are still silent and in early stage and therefore have a higher chance of a cure. The screening program should be performed in an experienced center to minimize radiation exposure and decrease unnecessary further testing / biopsies.
To inquire further about the Lung Cancer Screening Program at Moffitt Cancer Center, please call 1-888-MOFFITT.