Low-Dose Computed Tomography (LDCT): a promising method for lung cancer screening AUTHORS:
Mohammad Zare Mehrjardi
1,
2
; Morteza Sanei Taheri
1
; Hamid Reza
Haghighatkhah 1; Yasaman Arjmand 1; Seyed Yahya Hosseini Nasab 1
Department of Radiology, Shohada Tajrish Hospital, School of Medicine, Shahid Beheshti University of Medical
Sciences, Tehran, Iran 2
Section of Cardiothoracic Imaging, Division of Clinical Research, Climax Radiology Education Foundation, Tehran,
Iran Address correspondence to: Dr Mohammad Zare Mehrjardi (
[email protected])
OBJECTIVE To investigate the value of chest low-dose computed tomography (LDCT) and its recommended application in the high risk population for lung cancer screening in a systematic review of guidelines.
BACKGROUND Lung cancer has the most annual burden than any other cancer. It has been the most common cancer worldwide, both in incidence and mortality since universal tobacco smoking began. Since symptoms of this disease commonly manifest in higher stages, screening in order to early detection is advocated. The screening test should be easily available, with acceptable cost versus benefit and detection rate. There are mainly three suggested screening methods for lung cancer in the literature, that are simple chest X-ray, sputum test, and chest low-dose computed tomography.
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MATERIALS AND METHODS The PubMed search engine and three other databases were searched for the keywords “Lung cancer screening”, “guideline”, “low- dose computed tomography”, and related terms and guidelines published between January 2000 and September 2015, without language restrictions were retrieved. Reference list of the guidelines were also searched. Study data were extracted by the two reviewers independently and disagreement was resolved by consensus. The study quality was assessed by using items from the Quality Assessment of Diagnostic Accuracy Studies tool. Meta-analysis was done to calculate the sensitivity and specificity of LDCT in lung cancer detection and its reduction rate in lung cancer mortality using random effects modeling.
RESULTS Among nine retrieved guidelines, eight were of good quality which were recommendations from American Cancer Society (ACS), U.S. Preventive Services Task Force (USPSTF), American College of Chest Physicians (ACCP), American College of Radiology (ACR), National Comprehensive Cancer Network (NCCN), American Association for Thoracic Surgery (AATS), and American Lung Association (ALA), American Academy of Family Practice (AAFP). All the guidelines but the AAFP recommend chest LDCT as the choice method for screening and declare that other methods may not reduce the mortality rate from lung cancer. AAFP implicates that till now, evidence is not sufficient to recommend for or against screening. Seven (87.5%) guidelines that suggest screening by LDCT agree on smoking history of equal and more than 30 pack year who either currently smokes or have quit within the past 15 years as the definite indication for screening. They mention that screening should be started at 55 years old in this population. Two guidelines (i.e. NCCN and AATS) recommend screening in equal or more than 20 pack year history of smoking if there is an additional risk factor or comorbidity and in these population the screening should be begun by the age of 50.
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Majority of guidelines were based on four grand studies (two cohort and two retrospective) with a total 2788 citations, the biggest one was National Lung Screening Trial (NLST). Data from these studies showed a sensitivity of 91.4% (SD= 4.56) and specificity of 72.1% (SD= 5.28) for LDCT with a 17.3% (SD= 2.1) reduction in lung cancer mortality after long term follow-up.
CONCLUSION There was a controversy regarding cost and benefit of LDCT for lung cancer screening before NLST trial. NLST lightened up the true effectiveness of low dose CT in detecting lung cancer patients in American society in 2011. Since then, other studies have validated NLST’s results in early detection of this cancer. Since this disease is the leading cause of cancer death worldwide, we recommend low dose CT (LDCT) as a promising screening method for lung cancer based on our review.
RECOMMENDED CITATION: Zare Mehrjardi M, Sanei Taheri M, Haghighatkhah HR, Arjmand Y, Hosseini Nasab SY. Low-Dose Computed Tomography (LDCT): a promising method for lung cancer screening. 32nd Iranian Congress of Radiology (ICR), Tehran, May 3−6, 2016. Abstract book:122-3.
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