The document reviews current topics in lung cancer imaging, including updates on lung cancer screening, management of small lung nodules, and the limitations of PET/CT for staging. It emphasizes the importance of low-dose CT screening for high-risk patients, the statistics from the NLST study, and the necessity for insurance coverage for screenings. Additionally, it discusses the challenges of overdiagnosis and radiation exposure while outlining the Fleischner guidelines for follow-up care of lung nodules.

1. CURRENT TOPICS IN LUNG
CANCER IMAGING
Kenneth M. Neigut, M.D.

2. Overview
 Review lung cancer screening updates.
 Management of small lung nodules detected
on CT.
 The role and limitations of using PET/CT for
staging.

3. Lung cancer screening.

4. ACR position on CT lung
cancer screening.
 “Today’s USPSTF draft recommendation
marks a dramatic shift in views towards
diagnosing and treating lung cancer.”
 “Expanded use of lung cancer screening in
high risk patients is a landmark step in the
battle to defeat this terrible disease.”
Paul Ellenbogen MD, FACR, chair of the
American College of Radiology Board of
Chancellors

7. NLST
 53,454 current or former heavy smokers from
33 sites across US.
 Half received low-dose CT, half PA chest x-
ray (randomized trial).
 Three annual screenings were performed.
 Study began in 2002.
 Final results published in NEJM 8/4/2011.

10. NLST
 24% of all CT screens = positive
 96% of positive studies = false positives
 36% of all CTs = false positive
 39% (CT) participants = at least one positive
study
 False negative = “missed rate”= estimated to
be between 0-20%.

11. False Positive

12. Risk
 Radiation Dose
-- CXR = 0.08 mSv
-- Mammo = 0.07 mSv
-- CT: Chest = 7 mSv; 3 phase hepatic = 30 mSv
-- NLST Low dose CT = 1.4 mSv
 Non-Medical
-- Yearly Background = 3-5 mSv
-- Chicago = 3 mSv; Denver = 6 mSv (1.5 mSv/ 3 mos.)
-- Ramsar, Iran = 100-280 mSv; airplane 10 hours = 0.04 mSv
www.nrc.gov; www.world-nuclear.org

13. New ultrafast CAT scan:

14. USPSTF Recommendations:
 Screen high-risk patients (55-79 years old
with a 30 pack year or greater history of
smoking and continue to smoke or quit fewer
than 15 years ago).
 Annual lung cancer screening.
 Find tumors early, when they are most
treatable.
 Benefits outweigh risks.

15. Facts:
 160,000 lung cancer deaths occur in the
United States every year.
 85% of these deaths occur in those with a
strong smoking history.
 Lung cancer is the number one cancer killer.
 Insurance companies will be required to cover
the $300-400 screening under a mandate in
the federal health law.

16. Downside of screening:
 Overdiagnosis
 Excess radiation exposure
 Lung biopsies for growths that turn out not to
be cancer.

17. Screening:
 USPSTF estimates that screening 287,000
high risk patients would prevent 521 cancer
deaths but cause an additional 24 cancer
deaths from excess radiation exposure.
 Some advocate broader screening criteria,
applying to those who smoke less but have
other risk factors such as a family history of
lung cancer or exposure to asbestos or other
carcinogens.

19. Fleischner - Nodule

20. Fleischner - not used when
cancer history

21. Subsolid nodules
 Ground glass (subsolid) nodules are less
dense than solid nodules and the surrounding
pulmonary vasculature and do not obscure
the lung parenchyma.
 Can be purely ground-glass in appearance or
can have mixed solid and ground-glass
components.
 Dilemma: morphologic characteristics of a
ground-glass nodule are less well described.

22. Fleischner – Subsolid (GGO)

23. GGO turns solid - cancer

25. PET/CT: Limitations
 False positive
Infections
Inflammation – alveolitis
Tumor necrosis
 False negative
Bronchioloalveolar cell carcinoma
Small size (detection unreliable if <7mm nodule).

26. PET/CT Staging: N3 (mets to
contralateral nodes).

27. Summary
 Lung cancer screening with low dose CT will
allow earlier lung cancer detection and save
lives.
 Fleischner guidelines for lung nodule follow
up now include subsolid nodules.
 Be aware of the limitations of PET/CT.

29. End