How Much Should One Expect Lung Cancer Claiming to Increase Now that Low Dose CT Scans are Cheap and
It’s always good to listen to experts; sometimes the message also will be accurate. In the late 2000s, I chaired an international asbestos conference in London, and listened carefully to the comments of a British doctor who seemed respected by both sides of the bar. He made the then-remarkable assertion that low dose CT scans would over time become common and inexpensive, and would be found effective for finding early stage lung tumors. His prediction was surprising but sensible. It turns out he was right.
As shown in a post yesterday, low dose CT scans are now available "on sale" at $99 or for ordinary prices in the hundreds of dollars. And, last week, the New England Journal of Medicine published the results of a decade long study of results from using low dose CT scans. Not surprisingly, the study concluded that indeed low dose CT scans do find tumors early, and much more can be done to extend life when a lung tumor – of any kind – is found at stage 1 or 2. A basic summary of the article is online here. The abstract is online here at the NEJM, and is pasted below. The full article can be purchased at that site.
One resulting question is: how much should one expect lung cancer claiming to increase, and for how long? The overall annual numbers for lung cancer are massive when contrasted against the 2,000-3,000 annual mesotheliomas in the US.
"The American Cancer Society’s estimates for lung cancer in the United States for 2013 are:
About 228,190 new cases of lung cancer (118,080 in men and 110,110 in women)
An estimated 159,480 deaths from lung cancer (87,260 in men and 72,220 among women), accounting for about 27% of all cancer deaths
Lung cancer is by far the leading cause of cancer death among both men and women. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined
Lung cancer mainly occurs in older people. About 2 out of 3 people diagnosed with lung cancer are 65 or older; fewer than 2% of all cases are found in people younger than 45. The average age at the time of diagnosis is about 70.
Overall, the chance that a man will develop lung cancer in his lifetime is about 1 in 13; for a woman, the risk is about 1 in 16. These numbers include both smokers and non-smokers. For smokers the risk is much higher, while for non-smokers the risk is lower.
Black men are about 20% more likely to develop lung cancer than white men. The rate is about 10% lower in black women than in white women. Both black and white women have lower rates than men, but the gap is closing. The lung cancer rate has been dropping among men over the past 2 decades and has just recently begun to drop in women."
Set out below is the abstract from the NEJM paper on the lung cancer screening. One bottom line is that lung cancers were found in slightly less than 1% of the persons screened. Another bottom line is that low dose CT scanning resulted in finding slightly more than twice as many stage 1 tumors (158) as were found using x-rays (70).
"Results of Initial Low-Dose Computed Tomographic Screening for Lung Cancer
The National Lung Screening Trial Research Team
N Engl J Med 2013; 368:1980-1991May 23, 2013DOI: 10.1056/NEJMoa1209120
Lung cancer is the largest contributor to mortality from cancer. The National Lung Screening Trial (NLST) showed that screening with low-dose helical computed tomography (CT) rather than with chest radiography reduced mortality from lung cancer. We describe the screening, diagnosis, and limited treatment results from the initial round of screening in the NLST to inform and improve lung-cancer–screening programs.
At 33 U.S. centers, from August 2002 through April 2004, we enrolled asymptomatic participants, 55 to 74 years of age, with a history of at least 30 pack-years of smoking. The participants were randomly assigned to undergo annual screening, with the use of either low-dose CT or chest radiography, for 3 years. Nodules or other suspicious findings were classified as positive results. This article reports findings from the initial screening examination.
A total of 53,439 eligible participants were randomly assigned to a study group (26,715 to low-dose CT and 26,724 to chest radiography); 26,309 participants (98.5%) and 26,035 (97.4%), respectively, underwent screening. A total of 7191 participants (27.3%) in the low-dose CT group and 2387 (9.2%) in the radiography group had a positive screening result; in the respective groups, 6369 participants (90.4%) and 2176 (92.7%) had at least one follow-up diagnostic procedure, including imaging in 5717 (81.1%) and 2010 (85.6%) and surgery in 297 (4.2%) and 121 (5.2%). Lung cancer was diagnosed in 292 participants (1.1%) in the low-dose CT group versus 190 (0.7%) in the radiography group (stage 1 in 158 vs. 70 participants and stage IIB to IV in 120 vs. 112). Sensitivity and specificity were 93.8% and 73.4% for low-dose CT and 73.5% and 91.3% for chest radiography, respectively.
The NLST initial screening results are consistent with the existing literature on screening by means of low-dose CT and chest radiography, suggesting that a reduction in mortality from lung cancer is achievable at U.S. screening centers that have staff experienced in chest CT. (Funded by the National Cancer Institute; NLST ClinicalTrials.gov number, NCT00047385.)
The Lung Screening Study (LSS) of the National Lung Screening Trial (NLST) was supported by contracts with the University of Colorado Denver (N01-CN-25514), Georgetown University (N01-CN-25522), the Pacific Health Research and Education Institute (N01-CN-25515), the Henry Ford Health System (N01-CN-25512), the University of Minnesota (N01-CN-25513), Washington University in St. Louis (N01-CN-25516), the University of Pittsburgh (N01-CN-25511), the University of Utah (N01-CN-25524), the Marshfield Clinic Research Foundation (N01-CN-25518), the University of Alabama at Birmingham (N01-CN-75022), Westat (N01-CN-25476), and Information Management Services (N02-CN-63300). The American College of Radiology Imaging Network (ACRIN) was supported by grants under a cooperative agreement with the Cancer Imaging Program, Division of Cancer Treatment and Diagnosis (U01-CA-80098 and U01-CA-79778).
Dr. David Gierada reports receiving support through his institution from VuCOMP through a contract to provide medical images for use in the development of computer-aided diagnosis software. No other potential conflict of interest relevant to this article was reported.
Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.
The members of the writing team (who are listed in the Appendix) assume responsibility for the integrity of the article.
We thank those who volunteered to be participants in the trial for their contributions that made this research possible.
The members of the writing group are listed in the Appendix.
Address reprint requests to Dr. Timothy R. Church at the Division of Environmental Health Sciences, University of Minnesota School of Public Health, 200 Oak St. SE, Suite 350, Minneapolis, MN 55455, or at firstname.lastname@example.org.
A complete list of members of the National Lung Screening Trial Research Team is provided in the Supplementary Appendix, available at NEJM.org.