胸部X光檢查可以發現早期肺癌嗎？

 

Can Chest X-Rays Find Lung Cancer Early?

Recent News About Peter Jennings Raised Questions About Lung Cancer Screening

WebMD Health News

Reviewed by Charlotte E. Grayson Mathis, MD

 

WebMD News Archive

 

April 8, 2005 -- When the news that Peter Jennings had lung cancer hit earlier this week, many WebMD users asked why doctors don't use chest X-rays to diagnose lung cancer at an early stage, when it's more treatable.

WebMD turned to cancer expert Harold Burstein, MD, assistant professor of medicine at Harvard Medical School in Boston, for the answer.

Lung Cancer Most Preventable

"Lung cancer is the No. 1 cause of cancer death in the U.S. for both men and women. The vast majority of lung cancer cases are caused by smoking," Burstein tells WebMD. "Thus, lung cancer simultaneously represents the most devastating cancer in our society, and the most preventable."

He says there are good screening tests for many types of cancer, such as the Pap smear for cervical cancer, the mammogram for breast cancer, and colonoscopy for colorectal cancer.

 

 

 

But what about chest X-rays for lung cancer?

Too Late for a Cure

"The answer is surprisingly complex," he says.

Chest X-rays are inadequate for diagnosing lung cancers at an early stage, when they are more treatable.

"By the time lung cancers are discovered on chest X-ray, the tumor is often too far advanced to allow the patient to be cured with surgery or radiation therapy. Chest X-rays often miss small, potentially curable lung tumors, as they are too hard to see," says Burstein.

In addition, many things seen on a chest X-ray turn out to be artifacts or benign problems. "If you start getting lots of screening chest X-rays, you end up performing other testing on many patients, which are often unnecessary."

In recent years a lot of attention has been paid to high-tech scans called high resolution, spiral CT scans. The hope was that these CT scans would be able to find smaller, earlier cancers without leading to further unnecessary tests.

"A variety of recent studies in the U.S. and Japan have suggested that high-resolution CT scans can often detect lung cancers. In particular, these cancers seem to be small (stage I), suggesting that they may be more likely to be cured with surgery," says Burstein.

However, he explains that these were small, early studies that were not able to answer the questions of whether CT scans can actually save lives.
 

Burstein says a recent analysis of potential lung cancer screening tests shows there is inadequate data to recommend widespread lung cancer screening at this time.

The report by the federal Agency for Healthcare Research and Quality and the U.S. Preventive Health Services Task Force says evidence that chest X-rays, CT scans, and other forms of screening can save lives is poor.

"In the case of lung cancer, prevention remains the best cure. If you care about someone, try to get them to stop smoking," Burstein says.

http://www.webmd.com/lung-cancer/news/20050408/can-chest-x-rays-find-lung-cancer-early?page=2

Screening for Lung Cancer

Screening is looking for cancer before a person has any symptoms. This can help find cancer at an early stage when it may be easier to treat. Lung cancer may have spread by the time a person has symptoms. One reason lung cancer is so serious is because it usually is not found until it has spread and is more difficult to treat.

Screening may provide new hope for early detection and treatment of lung cancer. Scientists study screening tests to find those with the fewest risks and most benefits. They look at results over time to see if finding the cancer early decreases a person's chance of dying from the disease.

Three screening tests have been studied to see if they decrease the risk of dying from lung cancer:

• Chest x-ray: An x-ray of the organs and bones inside the chest. Chest x-ray is no longer recommended for screening.
• Sputum cytology: Sputum cytology is a procedure in which a sample of sputum (mucus that is coughed up from the lungs) is viewed under a microscope to check for cancer cells
• Low-dose spiral CT scan: A procedure that uses low-dose radiation to make a series of very detailed pictures of areas inside the body.

Of these tests, studies showed that only low-dose spiral CT scan reduced the risk of dying from lung cancer in high-risk populations. Chest x-ray and sputum cytology are two screening tests that have been used to check for signs of lung cancer but do not decrease the risk of dying from lung cancer.
http://www.lung.org/lung-disease/lung-cancer/learning-more-about-lung-cancer/diagnosing-lung-cancer/screening-for-lung-cancer.html

 

Screening for Lung Cancer

Most lung cancers are first diagnosed based on symptoms. Symptoms of lung cancer are not very specific and generally reflect damage to the lungs’ ability to function normally. The most common symptoms are a worsening cough that will not go away, and chest discomfort. Other symptoms include shortness of breath, spitting up small amounts of blood, unexplained weight loss, back pain, loss of appetite, and a general fatigue.

Unlike mammography for breast cancer or colonoscopy for colon cancer, a widely accepted screening tool for early-stage lung cancer has not been available until recently. Regular chest X-rays are not reliable enough to find lung tumors in their earliest stages, when many doctors believe the tumors are at their smallest and most curable state.

Recent guidelines from the American Society of Clinical Oncologists suggests annual screening with low-dose computed tomography (LDCT) for smokers and former smokers at high risk for developing lung cancer. High risk factors include being between the age of 55 to 74, having smoked for 30 years or more, and either continuing to smoke or having quit within the past 15 years. At this time, yearly screening with LDCT is recommended for high-risk individuals after careful discussion with their physicians.

http://www.lungcancer.org/find_information/publications/163-lung_cancer_101/274-screening