Lung Cancer -- Is It Time To Start Screening?

 

You have good reason to be concerned. Approximately 220,000 Americans developed lung cancer last year, and the vast majority of these people smoked at some point in their life. Although other factors can contribute to lung cancer — including asbestos or other occupational and environmental exposures — smoking cigarettes is by far the most important. Forty-five million people in the United States continue to smoke, and an equal number of ex-smokers remain at high risk of cancer and other deadly smoking-related diseases.

 

Despite progress in many areas of medicine, the statistics for lung cancer remain grim. Death rates are about the same today as they were 30 years ago. More than 85 percent of those diagnosed with lung cancer will die of the disease. The total number of lung cancer deaths has gone down slightly in the past decade, mainly because of lower smoking rates for men. However, lung cancer still causes more deaths each year than do cancers of the breast, prostate and bowel combined.

 

 

Most cancers start very small and grow slowly. If cancer can be detected at a very early stage — before it causes symptoms or spreads to other parts of the body — the chance for cure improves dramatically. In fact, screening for the early stages of disease is very effective for a number of cancers, including cancer of the breast (mammography), colon (colonoscopy) and cervix (Papanicolaou, or Pap, smears).

 

Lung cancer seems to be different, however. Several large studies conducted in the United States and elsewhere have looked at whether chest X-rays and sputum samples can detect lung cancer early. Although such screening increases the number of early stage cancers detected and improves overall survival, there has been no documented decline in lung cancer deaths.

 

Why these confusing results? The explanation is complicated and somewhat controversial. However, most experts agree that the apparent benefits of screening result from a statistical "sleight of hand." The fact that several studies failed to show a decline in the lung cancer death rate — what scientists consider to be the "gold standard" for screening tests — leads to the conclusion that chest X-rays and sputum samples are simply not effective in detecting lung cancer. To this day, most cancer experts and advisory panels recommend against screening for lung cancer with regular chest X-rays.

 

Yes, CT scans of the lungs are better. Computed tomography, better known as a CT scan, is a technologically advanced type of X-ray that creates a three-dimensional picture of the lung. CT scans can find tiny growths that would be missed by most ordinary X-rays. The latest scanners are quick and use only modest doses of radiation.

 

Researchers have published impressive studies that show these scans can detect very small, early-stage lung cancers. Until recently, early detection was not shown to improve lung cancer survival. However, the results of a large study called the National Lung Screening Trial were published in June 2011. The report suggests that screening heavy smokers with yearly low-dose CT scans can reduce deaths from lung cancer by 20% compared to screening with chest x-rays.

 

 

Before you ask your doctor for the CT scan, be aware that most insurance companies will not pay for the test. So be prepared to spend several hundred dollars out-of-pocket. Medicare and other insurers are waiting for further analysis of the study results. In addition to the monetary expense, there are physical and emotional costs. In the study, about 24% of the CT scans showed areas of concern that required additional testing to determine if lung cancer were present. Yet 95% of these positive screens were "false positives." The abnormality turned out to be lymph nodes or inflamed tissue rather than lung cancer. While something that looks like cancer but isn't would be a result that any one would hope for, it took follow-up imaging, a biopsy of lung tissue, or bronchoscopy (in which a tube is threaded down into the airway) to make the final diagnosis. In addition to generating worry or even panic, these false positives sometimes led to injury during the follow-up procedures.

 

 

Studies to examine the effectiveness of screening for lung cancer with CT scans are still ongoing. With the jury out, doctors remain divided on whether to offer CT scans to individuals who wish to be screened. If you are very worried about lung cancer and are willing to try an experimental screening test, I am certain that you can find a local hospital that offers this type of CT scan (often known as a low-dose, spiral or helical CT). Most insurance companies will not pay for this test, so be prepared to spend several hundred dollars out-of-pocket. Whether this is a worthwhile investment remains to be seen.

 

However, there are other reasons not to have this type of test. Although the radiation dose is less than that in a typical CT scan, it is still 10 times more than that in a chest X-ray. No one is sure of the long-term effect of getting this amount of radiation every year. Furthermore, for every cancer detected, there are about 10 individuals with an abnormal scan that requires follow-up. About 20% of people who get a scan have a suspicious spot that requires one or more follow-up scans. Although few biopsies or surgeries were performed for spots that turned out to be benign, the need to monitor these people required considerable time, money and radiation exposure, not to mention anxiety on the part of those individuals who were told that their scan was abnormal.

 

 

This is always the tough question. If a screening test is inexpensive and never results in any harm, then the answer could be use. But this is never the reality. To keep one person from dying of lung cancer, an estimated 320 heavy smokers need screening with yearly CT scans. Or put another way, 319 out of 320 people who get screened will not benefit from screening. And some will be harmed.

 

 

CT scans can't prevent lung cancer. At best, they might detect lung tumors early enough that they can be cured by surgery. The best way to prevent lung cancer is to never smoke or to quit. One of the lessons we've learned it that it is never too late to quit. If you quit at age 60, you stand to tack on about three years to your life expectancy. Quit at 50, and you earn six extra years. Quit at 30, and a whole decade is deposited into your life expectancy account. There's no better health deal around.