Why aren't lung cancers detected earlier?
This page was last updated on July 17, 2000.
Most lung cancers that are detected early are found by chest x-rays done as screening proceedures or by x-rays that are done for investigation of symptoms not suspected as being due to lung cancer. In my experience, the most common scenario is that of a patient who develops an upper respiratory viral cold or flu, and goes to his doctor. When the doctor orders a CXR, the lung cancer which was not responsible for the symptoms is found. CXRs is a good, but flawed method. Small lesions (<1cm.) are frequently missed even by excellent radiologists. Early lung cancers can be missed when they arise in hidden areas of the lung i.e. behind the heart or blood vessels at the root or hilum of the lung. One of my patients, Marie Kaplan RN, describes her experience in this article reprinted with permission from Nurse Week. SCREENING FOR LUNG CANCER Marie Kaplan, BS RN Should people who are asymptomatic be screened for lung cancer? How about screening for asymptomatic smokers since 80% to 90% of lung cancer is caused by smoking? According to The American Cancer Society, "Lung cancer is the leading cause of death in both men and women. The 5 year survival rate for all stages of lung cancer is 14%. If lung cancer is found early, before it's spread to lymph nodes or other organs, the average survival rate is 48%. However, only 15% of lung cancers are found at this early localized stage" I am among the fortunate l5%. Because of my recent lung cancer experience I am concerned about the need for lung cancer screening. In March of 1995 I was asymptomatic when I saw my doctor for a routine yearly physical. My lung X-ray showed cancer in my right lung, and a subsequent CT scan showed cancer in my left lung. I was initially diagnosed as having late stage metastatic cancer. After six months of unsuccessful chemotherapy, I went to City of Hope National Medical Center in Duarte for a second opinion and the diagnosis was changed to early stage cancer. They decided the cancers in both lungs had started simultaneously. Synchronous cancer in both lungs is unusual and many people do not realize it's possible I had 2 surgeries and I'm still well. Yearly X-rays Both my family doctor and lung surgeon believe so strongly in lung cancer X-rays they themselves undergo them yearly. Why then, in spite of the frightening statistics, do so few doctors believe in regular lung cancer screening? My lung surgeon pointed out that cancers in certain areas of the lungs do not show up on X-ray, but this is just part of the story. A review of the literature showed that in the 1970's The National Cancer Institute conducted 3 large U. S. long range randomized cancer screening studies. A 4th study was done in Czechoslovakia. All the trials showed the ability to diagnose lung cancer early, but MORTALITY REDUCTION WAS NOT FOUND IN ANY OF THE STUDIES. Therefore, at present, guidelines from groups such as The American Lung Society, The American Cancer Society, and The American Thoracic Society do not advise routine lung cancer screening. The 1990 journal CA gives figures from two American Cancer Society surveys. They show only 40% of physicians indicated they ever screened asymptomatic high risk individuals for lung cancer. 96 to 98% of these same physicians screen for breast, cervical, prostate, and rectal cancers. As a result the vast majority of lung cancer patients are symptomatic on diagnosis which is too late for curative surgery. Questioning assumptions In March of 1997 CHEST magazine aplanpublished an article on the research of Dana Farber Cancer Institute reanalysing and questioning the idea that lung cancer screening is not indicated because no randomized trial showed a reduction in mortality. Perhaps the wrong question is being asked and mortality is not necessarily the most reliable measure of the effectiveness of lung cancer screening. Dana Farber Cancer Institute says that if you screen you pick up more early stage disease and people will live longer. They say, "Serious reconsideration should be given to the question of whether periodic chest X-rays should be recommended for individuals with high risk for lung cancer. I feel that asymptomatic people, particularly smokers, should have regular screening for lung cancer. Mass screening may not be economically feasible, but screening on an individual basis can be life saving." ============================================================== There is important new information on Sceening!This link presents a view that I disagree strongly with. This is the orthodox view that is espoused by most organizations in the U.S. MASS SCREENING FOR LUNG CANCER
Frederic W. Grannis Jr. M.D If you have trouble contacting me with the address above, I may also be reached at 76516,2333@compuserve.com and at fgrannis@cris.com |