Towards an Early Lung Cancer Detection and Screening ... · for lung cancer or unwilling to be...
Transcript of Towards an Early Lung Cancer Detection and Screening ... · for lung cancer or unwilling to be...
Towards an Early Lung Cancer
Detection and Screening Protocol
for the Ridge Meadows Area Grand Rounds December 2015
Frank Ervin, MD, FRCPC, FCCP
Lung Cancer
• High case fatality ratio
• Leading cause of cancer death
• Improved survival with earlier stage disease
• High risk population identifiable
• Goals of screening programs
• Sources of bias in studies of screening programs
• Benefits and risks of Low dose CT scans for lung
cancer screening
• Current recommendations for CT screening
programs
• CT screening in BC
• Who should be referred for screening and how?
Screening: Rationale
• Screening individuals at risk for a disease before
they have signs or symptoms of the disease
• Treat the disease when found on screening aiming
to improve outcomes, lower morbidity and
mortality
• Achieve a reduction in disease related mortality
• Balance benefit with harms (pseudodisease,
morbidity and cost)
Overestimation of survival duration among screen-detected cases (relative to those detected by signs and symptoms) when survival is measured from diagnosis. This simply reflects earlier diagnosis because the overall survival time of the patient is unchanged.
Lead-time bias
http://www.vaoutcomes.org/downloads/Lead_Time_Bias.pdf
Patz EF Jr et al. N Engl J Med 2000;343:1627-1633.
Overdiagnosis bias
Overestimation of survival duration among screen-detected cases caused by inclusion of pseudo- disease—subclinical disease that would not become overt before the patient dies of other causes.
www.vaoutcomes.org/downloads/Lead_Time_Bias.pdf
Patz EF Jr et al. N Engl J Med 2000;343:1627-1633.
Length bias Overestimation of survival duration among
screening-detected cases caused by the relative excess of slowly progressing cases. These cases are disproportionately identified by screening because the probability of detection is directly proportional to the length of time during which they are detectable and thereby inversely proportional to the rate of progression
www.vaoutcomes.org/downloads/Lead_Time_Bias.pdf
Patz EF Jr et al. N Engl J Med 2000;343:1627-1633.
Risks of Screening for Lung
Cancer with LDCT
• Radiation induced cancers
• Anxiety
• Cost
• Overdiagnosis of indolent cancers
Screening with CXR
• Several studies from 1960 through 2011 studied
CXR +/- sputum cytology
• PLCO study negative
• Lung cancer incidence/ 10,000 pt-yrs varied by
smoking history: 3.1, 23 and 83 in never, ex and
current smokers
The National Lung Screening Trial Research Team . N Engl J Med 2011;365:395-409.
The National Lung Screening Trial Research Team . N Engl J Med 2011;365:395-409.
The National Lung Screening Trial Research Team . N Engl J Med 2011;365:395-409.
The National Lung Screening Trial Research Team . N Engl J Med 2011;365:395-409.
Video
N Engl J Med 2013; 369:910-919
Probability of cancer in nodules detected on screening
http://www.nejm.org/doi/full/10.1056/NEJMoa1214726
McWilliams A et al. N Engl J Med 2013;369:910-919.
McWilliams A et al. N Engl J Med 2013;369:910-919.
Radiation Risks
• Current low dose algorithms: 1.5 mSv
• Average annual background radiation: 3-4 mSv
• Repeat screening to follow small nodules often
needed
• Average NSLT dose over three years 8 mSv,
maximum 20-22 mSv over 4 years
Radiation Risks
• “Risks of medical imaging at effective doses
below 50 mSv for single procedures or 100 mSv
for multiple procedures over short time periods
are too low to be detectable, and may be
nonexistent”
• Estimate risk of radiation induced cancer in
NSLT is one cancer death in 2,500 screened
participants
Risks of Screening
• Small increase in risk of death in screened
patients in the NSLT
• Death or major complications/10,000
participants:
• 4.1 and 4.5 in LDCT arm
• 1.1 and 1.5 in CXR arm
Recommendations
ACCP May 2013
• Smokers and former smokers
• 30 pack years or more
• Not quit for 15 years
• Annual screening with LDCT should be offered
US Preventive Services Task Force
Recommendation Statement
March 2014
• Asymptomatic adults aged 55-80 years
• 30 pack year smoking history
• Current and former smokers < 15 years quit
Caveats
• Persons screened should be relatively healthy
and be willing and able to undergo curative
treatment for any cancers found
• The screening program should include smoking
cessation counselling
• The program should model that of the NLST in
terms of quality of scan interpretation, follow up
of nodules, patient selection, etc.
Who benefits most from
screening?
• In the NLST persons in the highest 60% of risk
accounted for 88% of all deaths preventable by
screening
Screening programs in BC
• No formal screening program exists
• VGH Lung Health Study
• Interested respirologists/radiologists
Suggestions for Screening Your Patients
or…
“It is easier to get into something than to get
out of it.” - Donald H. Rumsfeld • Identify patients who meet either the NLST or USPSTF criteria
• Do not suggest screening for patients who are too ill to be treated
for lung cancer or unwilling to be followed
• Explain the benefits and risks of screening
• Ensure that the CT requested is “Low Dose CT Chest for Screening”
and include the number of pack years, quit times, asbestos
exposure, etc
• Ensure that the CT report is reviewed and that follow up CT Scans
are ordered per the radiologist’s recommendation
• Promptly refer patients for further assessment as needed.
Practical Issues for Maple
Ridge • Should we be offering screening to the general
public, advertise in local papers, etc.?
• Who orders the repeat CT scans: GP,
Respirologist, Radiologist?
• Should we maintain a registry of screened
patients?
• Where is the funding for this? Consult and visit
fees? Counselling?
Towards an Early Lung Cancer
Detection and Screening Protocol
for the Ridge Meadows Area Grand Rounds December 2015
Frank Ervin, MD, FRCPC, FCCP