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LDCT

EK

Ela Kuklina

Transcript

LDCT:

reduced lung cancer mortality

Faissal, Audrey, Nadia, Ela, Elianne

Context of the study

#1 cause of cancer deaths

200,000 - 160,000

National Lung Screening Trial

2002 - 2010

Goal:

Determine whether LDCT could reduce lung cancer mortality

Status Quo

Status Quo

  • Before the study: No screening without symptoms

http://www.youchoimd.com/lungcancer.html

Techniques

Techniques

http://www.wikiradiography.net/page/Left+Lower+Lobe+Consolidation

https://images.radiopaedia.org/images/157288/4c1383482027c97c445f418c9b74b3_big_gallery.jpg

Low Dose Comupted Tomography (LDCT)

Low Dose Comupted Tomography (LDCT)

  • Form of CT scan used to detect early-stage lung cancers
  • Uses 5x less radiation dose compared to conventional CT
  • No injections of contrast agents
  • Visualizes abnormal lung nodules as small as 2 to 3 millimiters
  • 3D image with growth detectable in all directions

CT (Chest)

LDCT

1-1.5 mSv

7-8 mSv

Technical aspects

  • Scanning time (breath-hold duration): 30 seconds
  • Multidetector row CT (MDCT) allows faster scanning and lower slice thickness
  • Optimal spatial resolution must be ensured
  • Acquisition variables set to maintain low radiaton
  • Tube voltage: 90-140 kVp
  • Tube current: 20-80 mA
  • Reconstruction slice thickness: <1.5 mm
  • Reconstruction interval: 0.7-1.25 mm
  • Smoothing algorithms enhanceme nodule attenuation

Chest radiography (CXR)

Chest radiography (CXR)

  • 2D image generation using conventional X-ray
  • Common first imaging step in cardiovascular, respiratory and systemic diseases
  • Radiation: Around 0.02 mSv (PA) or 0.08 mSv (LL)

Screen-Film: Silicon films

Computed Radiography (CR): Phosphor imaging plate

Digital Radiography (DR): Digital detector

https://image.slidesharecdn.com/chestx-rayinterpretation-140525084631-phpapp01/95/chest-x-ray-interpretation-5-638.jpg?cb=1401007746

Methods

Positive/negative results

Positive/negative results

Technical parameters

Technical parameters

LDCT

Chest Radiography

Results

https://www.yoyojobs.com/wp-content/uploads/2017/03/Latest-Sarkari-Results-For-Various-Exams.png

Results of screening

Results of screening

LDCT: More positive results diagnosed: 39.1% vs 16.0%

LDCT: More abnormalities crossing out cancer detected !

Positive Results follow-up

How many positive confirmed ?

How many positive confirmed ?

  • T0: 3.8% LDCT and 5.7% radiography
  • T1: 2.4% LDCT and 4.4% radiography
  • T2: 5.2% LDCT and 6.6% radiography

Means 96.4% false positives with LDCT

and 94.5% false positives with radiography

Better be safe than sorry?

How many positive confirmed ?

How many positive confirmed ?

LD-CT: Total of 1060 lung cancer diagnosed ↔ 645 per 100,000 person-year

  • 649 was diagnosed after a positive screening test
  • 44 were diagnosed after a negative screening test (false negative)
  • 367 were diagnosed after either missing their screening or received a positive diagnostic after their trial screening phase

X-ray: Total of 941 lung cancer diagnosed ↔ 572 per 100,000 person-year

  • 279 were diagnosed after a positive screening test
  • 137 were diagnosed after a negative screening test (false negative)
  • 525 were diagnosed after either missing their screening/ received a positive diagnostic after their trial screening phase

LD-CT: more people diagnosed earlier and less people diagnosed with a false negative.

Which stages?

Reminder: We want to reduce mortality

Which stages?

http://www.ourhealthpage.com/wp-content/uploads/2015/11/Stages-min.jpg

Which stages?

Which stages?

Both techniques could diagnosed many stage I and II, but the stage distribution was more favorable for LDCT.

What about the mortality ?

What about the mortality ?

Critical Appraisal

Critical Appraisal

Low-dose CT was chosen as a screening procedure that was a huge innovation in the field of lung cancer

specific characteristics

Advantages

Advantages

  • LDCT is more detailed → less false negative results
  • Radiation dose is very low
  • Can detect early stage lung cancer
  • Quick, painless, and non-invasive approach to screen for lung cancer 
  • Takes less than a minute to complete
  • Differentiation of nodule sizes is more specific for low dose CT compared to radiography
  • Recomended management is more specific

Disadvantages

Disadvantages

  • LDCT is not as avaliable and more expensive
  • Unnecessary exposure to radiation that can cause complications →smokers are more sensitive to x-ray exposure
  • Psychological burden of a false postive result

Limitations of the study & overdiagnosis

Limitations of the study & overdiagnosis

  • Healthy volunteer effect

  • Today's scanners and reconstruction methods are more advanced

  • Mortality rate of participants undergoing lung resection was lower than in real world scenarios (generalizability)

Limitations of the study & overdiagnosis

  • False positive findings and possible further (invasive) tests may cause anxiety and stress in patients
  • Exposure to risks of further procedures (e.g. biopsies, surgery)
  • False Alarm abnormalities found in 25% of participants
  • Detection of cancer that would have never harmed patient

  • US: 7 million meet screening requirements - screening capacity not yet given

Future prospects

Future prospects

... since the release of the study

LDCT screening program developped in the US

  • Medicare covers one screening per year
  • Important criteria
  • Smokers and those who quit within the last 15 years
  • Age 55-77
  • Minimum of 30 pack years

Non-invasive screening

  • Sputum (biomarkers, MEDLUNG study)
  • Fluorescence bronchoscopy
  • Liquid biopsy (blood sample)

Non-invasive screening

Questions?

Reference list

Reference list

  • National Cancer Institute (2014). "National Lung Screening Trial (NLST) Screening - Full Text View - ClinicalTrials.gov". clinicaltrials.gov.
  • Reduced lung-cancer mortality with low-dose computed tomographic screening.1. N Engl J Med. 2011 Aug 4;365(5):395-409. doi: 10.1056/NEJMoa1102873. Epub 2011 Jun 29.
  • P., P., G., S., K., T., . . . NLST Overdiagnosis Manuscript Writing Team. (2014). Overdiagnosis in low-dose computed tomography screening for lung cancer. Jama Internal Medicine, 174(2), 269-74. doi:10.1001/jamainternmed.2013.12738
  • Raman, S P, et al. “CT Scan Parameters and Radiation Dose: Practical Advice for Radiologists.” Journal of the American College of Radiology : JACR., U.S. National Library of Medicine, Nov. 2013, www.ncbi.nlm.nih.gov/pubmed/24183553.
  • Kelly, B. (2012). The Chest Radiograph. The Ulster Medical Journal, 81(3), 143–148.
  • Rampinelli, C., Origgi, D., & Bellomi, M. (2012). Low-dose CT: technique, reading methods and image interpretation. Cancer Imaging, 12(3), 548–556. http://doi.org/10.1102/1470-7330.2012.0049
  • How I Do It: Managing Radiation Dose in CT William W. Mayo-Smith, Amy K. Hara, Mahadevappa Mahesh, Dushyant V. Sahani, and William Pavlicek. Radiology 2014 273:3, 657-672
  • CDC - WHAT SCREENING TESTS ARE THERE FOR LUNG CANCER? In-text: ("CDC - What Screening Tests Are There for Lung Cancer?", 2018) Your Bibliography: CDC - What Screening Tests Are There for Lung Cancer?. (2018). Cdc.gov. Retrieved 1 February 2018, from https://www.cdc.gov/cancer/lung/basic_info/screening.htm
  • GETTING DIAGNOSED LUNG CANCER CANCER RESEARCH UK In-text: ("Getting diagnosed Lung cancer Cancer Research UK", 2018) Your Bibliography: Getting diagnosed Lung cancer Cancer Research UK. (2018). Cancerresearchuk.org. Retrieved 1 February 2018, from http://www.cancerresearchuk.org/about-cancer/lung-cancer/getting-diagnosed
  • LUNG CANCER - DIAGNOSIS AND TREATMENT - MAYO CLINIC In-text: ("Lung cancer - Diagnosis and treatment - Mayo Clinic", 2018) Your Bibliography: Lung cancer - Diagnosis and treatment - Mayo Clinic. (2018). Mayoclinic.org. Retrieved 1 February 2018, from https://www.mayoclinic.org/diseases-conditions/lung-cancer/diagnosis-treatment/drc-20374627
  • LUNG CANCER 101 LUNGCANCER.ORG In-text: ("Lung Cancer 101 Lungcancer.org", 2018) Your Bibliography: Lung Cancer 101 Lungcancer.org. (2018). Lungcancer.org. Retrieved 1 February 2018, from https://www.lungcancer.org/find_information/publications/163-lung_cancer_101/267-diagnosing_lung_cancer
  • DIAGNOSIS OF LUNG CANCER - CANADIAN CANCER SOCIETY In-text: ("Diagnosis of lung cancer - Canadian Cancer Society", 2018) Your Bibliography: Diagnosis of lung cancer - Canadian Cancer Society. (2018). www.cancer.ca. Retrieved 1 February 2018, from http://www.cancer.ca/en/cancer-information/cancer-type/lung/diagnosis/?region=on
  • Swedishorg. (2018). Swedishorg. Retrieved 2 February, 2018, from https://www.swedish.org/services/thoracic-surgery/our-services/lung-cancer-screening-program/low-dose-ct-scan-for-lung-cancer-screening
  • Koji ono. (2018). US National Library of Medicine National Institutes of Health. Retrieved 2 February, 2018, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3755805/
  • Xu xj , et al. (2018). Nihgov. Retrieved 2 February, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/17045006