BASED on a landmark federal study three years ago which found that the annual screening of older smokers and former smokers with special low-dose CT scans substantially reduces deaths from lung cancer - plus the fact that lung cancer kills 160,000 Americans a year, accounting for nearly one-third of all cancer deaths and more than breast, prostate and colon cancers combined - the American Cancer Society and American Lung Association last year endorsed such screening; and now, the U.S. Preventive Services Task Force (USPSTF), an independent panel of experts who advise the government, has issued recommendations supporting annual screening, says the November 2013 issue of the University of California, Berkeley Wellness Letter.

The USPSTF has issued draft recommendations that advocate yearly low-dose chest CT scans for high-risk current and former smokers who have no symptoms - smoking tobacco is responsible for 85 percent of all lung cancers.

It is updating its 2004 recommendations, after analyzing findings from several recent major lung cancer screening trials - the most significant of these is the National Lung Screening Trial (NLST) in which screening with low-density helical (spiral) CT resulted in a 20 percent relative-risk reduction in lung cancer death.

This screening protocol, which would include 7 to 10 million individuals, could save 120,000 lives a year, the Task Force estimated.

Meanwhile, the November 2013 issue of Johns Hopkins' HealthAfter 50 offers these criteria that makes you at high risk for lung cancer, and should be screened if you:

• Are a present smoker or a past smoker who’s quit within the past 15 years, and

• Are in the age group from 55 to 79 years, and

• Have a smoking history of at least 30 “pack-years” (this means either one pack a day for 30 years, two packs a day for 15 years or three packs a day for 10 years).

The NLST trial involved more than 53,400 men and women between ages 55 and 74, all current or former heavy cigarette smokers, defined as a 30 pack-year habit - former smokers included only individuals who had quit smoking less than 15 years from the start of the study.

All participants received either a chest X-ray or a CT lung scan every year for three years.

However, researchers abruptly halted the 10-year study at the eight-year mark when they discovered that 20 percent fewer individuals in the CT group died of lung cancer than in the chest X-ray group - continuing the trial without giving everyone the opportunity to receive CT lung scans would have been unethical, since the scans clearly saved lives in the study population, said the researchers.

CT scans also seem to be as good as other cancer screening tests, if not better, at finding cancer - researchers estimate that about 220 individuals would need a CT lung scan to prevent one lung cancer death: In contrast, routine prostate-specific antigen (PSA) screening for prostate cancer, where about 1,400 men have to be screened to save one life, and about 1,300 women ages 50 to 59 need a routine mammogram to save one life.

The USPSTF doesn’t recommend lung cancer screening using chest X-ray or sputum cytology - when mucus you cough up from your lungs is examined under a microscope - because they aren’t effective detectors of lung cancer.

CT scans are best at detecting non-small cell lung cancer - the most common type of lung cancer.

Surgical removal of the cancerous part of the lung is the typical treatment for non-small cell lung cancer.

Annual lung cancer screening for high-risk individuals is essential because:

• The goal of screening is to detect cancer early enough so it can possibly be cured.

More than 160,000 Americans die of lung cancer each year - the survival rate among individuals whose lung cancer was caught at its earliest stage is 77 percent.

• The USPSTF statistics show that 75 percent of lung cancer cases are diagnosed only after the disease has reached an advanced stage or spread to other parts of the body - the median five-year survival rate is 52 percent for individuals with lung cancer that hasn’t spread; whereas the five-year survival rate ranges from 4 to 24 percent for those with cancer that has spread.

• The risk for lung cancer peaks at  age 71, and two of three lung cancers are diagnosed after age 65 - the increasing risk of age for lung cancer is behind the USPSTF’s age range recommendations for screening 55 to 79 year olds.

However, the benefits of screening smokers after age 79 are questionable - doctors have to evaluate a patient’s overall health and ability to recover from treatment, if cancer is found.

This is also true for individuals of any age because the  potential risks of treatment may outweigh the potential benefits.

These screening drawbacks are offered:

• CT screening exposes you to some radiation - less than that of a normal CT scan, but close to the same amount as that of mammography and more than that of a chest X-ray, depending on your body weight, the CT scanner type and manufacturer, and the area of lung scanned.

• Lung CT screenings aren’t foolproof - they have a high rate of false-positives; that is, they frequently detect small lung nodules that are suggestive of cancer but aren’t cancerous.

According to the NLST results, 25 percent of scans showed abnormalities, but almost all turned out to be noncancerous.

• The high rate of false-positives exposes patients to unnecessary worry, repeated scans and radiation exposure, unnecessary lung biopsies and even needless surgery - which happened in approximately 1 percent of false-positive cases in the NLST study.

To lessen the risk of false-positives, CT scanning should be done in medical facilities with radiologists, oncologists and surgeons who have expertise in interpreting scans and treating cancer.

• A CT scan may cost between $300 to $500, and Medicare and some insurers may not reimburse you for these costs.

(There may also be additional charges from the facility where you undergo the scan.)

However, if the USPSTF’s draft recommendations are approved (which can take several months), Medicare will be required to cover the costs without a copay or deductible under the Affordable Health Care Act.

The best way to avoid lung cancer is not to smoke, and if you do, quit - other factors can contribute to lung cancer, such as exposure to secondhand smoke, radon, asbestos and certain substances in the workplace, but smoking by far does the most damage to your lungs.

In any case, if you are 55 to 79 years old and have smoked heavily for many years, discuss the pros and cons of lung cancer screening with your health care provider, concludes the health letter.

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