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Do I need Lung Cancer Screening?
Are you a Smoker or Former Smoker?
The majority of lung cancers are often caused by cigarette smoking and usually not detected until symptoms develop. By that time, the disease is often more advanced, making a cure much less likely.
This screening could save your life:
In October, 2011, the National Comprehensive Cancer Network (NCCN), a professional organization of the leading cancercenters in the United States, revised its guidelines on lung cancer screening. This was after the National Lung Screening Trial (NLST) findings reveal that those who received low-dose CT scans had a 20% lower risk of dying from lung cancer than those that received standard chest X-rays.
NCCN gave its highest recommendation (with a Category 1 level of consensus agreement) to CT screening for current smokers and former smokers (who quit within the past 15 years) with a 30 pack year history (number of packs a day times the number of years of smoking) who are between the ages of 55 and 74.
NCCN also recommendation to smokers
and former smokers, ages 50 and up, with a 20 pack year history who also had
one additional risk factor:
exposure to radon
exposure to occupational carcinogens, such as silica, cadmium, asbestos, arsenic, beryllium, chromium, diesel fumes and nickel
a previous cancer
a family history of lung cancer
COPD or pulmonary fibrosis
Second hand smoke exposure.
What are the risks involved?
Additional Testing
The goal of screening is to diagnose a cancer at an early stage when it is most treatable and curable. The step by step procedure for screening and determining whether suspicious findings are cancer or not cancer is called a protocol.
CT scanners can “see” minute lung abnormalities as small as a grain of rice. If the scan picks up any findings suspicious for lung cancer, such as nodules over a certain size, or enlarged lymph nodes near the lung, or a lesion in the main airways, it is classified as
a positive screen.
That does not mean that thesuspicious findings are definitely cancer. Many people, especially smokers or former smokers, will have a positive screen that could be caused by inflammation, scarring or other lung diseases rather than lung cancer.
About 10-20% of people screened for cancer by mammography, colonoscopy, PSA testing, or CT scans will have a positive screen, which requires additional testing. Most will be false positives and only a small percentage will prove to be cancer.
Positive screens will usually be followed by a second scan two or three months later to check for any change or increase in volume. Nodules larger than a grape found on the first scan, and those that appear to be growing on the second scan, may be further tested with a positron emission tomography (PET) scan to check for metabolic activity in the nodule that may indicate cancer.
A biopsy may be needed sovthat a small sample of tissue from the nodule can be examined under a microscope for cancer cells. Tissue is collected through a tube inserted down the windpipe (bronchoscopy) or with a needle through the chest wall
(percutaneous fine-needle aspiration). Both procedures entail some risk of bleeding, infection or collapsed lung and should only be done by experienced doctors.
Even with all these precautions, some nodules - about 0. 5% - that are not cancerous may end up being removed by unnecessary surgery. All lung surgery carries significant risk and after effects.
Anxiety
Understandably many people who have suspicious findings (a positive scan) will experience anxiety during the evaluation period. But studies have shown that anxiety rapidly disappears when subsequent tests rule out cancer. For those whose cancers are confirmed, their anxiety must be weighed against the benefit of having the tumor diagnosed at a very early stage when treatment can be most successful.
It must be emphasized that CT-based lung cancer screening is not a test, but rather a process. The approximately 15% of individuals who have a solid lung nodule larger than five mm or a non-solid nodule larger than eight mm in diameter have further testing to
determine if the individual with a nodule has a cancer (approximately 12%) or a
benign nodule (approximately 88%) in the lung. The type of test, the order of tests
and the time at which further testing should best be done is outlined in an organized plan called an algorithm or regimen.
The 88% of individuals who receive a negative report will logically be relieved of anxiety that might have been experienced before, during or after the performance of the CT scan. For this reason it is important to minimize the delay between performance of the scan and the generation of a report.
With respect to anxiety in screening, it should be understood that screened subjects start with a level of anxiety; that the reason for an individual enrolling in a screening program is anxiety about dying of cancer based upon information received in public health
information or from a private physician.
There is good data from multiple studies indicating that research subjects tolerate anxiety experienced before and during cancer screening, as well as anxiety caused by positive screening results, and consider it to be a reasonable tradeoff for the benefit they derive from screening.
Radiation
Screening scans that check people who have no symptoms for lung cancer are given at low dose. In fact, screening scans are referred to as low dose scans. Follow-up scans that may have to be done to determine if any change or growth has occurred should be at the same low-dose.
The radiation from a low dose CT screening scan has been reduced to about the same as a mammogram - from less than 1 to 1.5 millisieverts (mSv).
On average, people living in the United States are exposed to 3 mSv a year, and up to 10mSv at higher altitudes.
What if the nodule is cancerous?
Because most lung cancers found by screening are small size and early stage, treatment is most often surgery. However, surgery involves differing levels of risk (from less than 1% to as high as 5%) depending on the type of surgery (removal of a wedge section, a lobe or an entire lung) and the experience of the surgeon. This will be discussed with you more in detailed by your physician is this occurs.