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Scientific Session 13 — Chest Imaging

Wednesday, May 3, 2017

Abstracts 1085-3299



2901. Lung Cancer Screening CT: Correlating Degree of Centrilobular Emphysema to Pack-Years of Smoking

Riyaz F*,  Pillutla A,  Parker M,  Powell T,  Edelstein M. Virginia Commonwealth University Health System, Richmond, United States

Address correspondence to M. Pillutla (avinash.pillutla@vcuhealth.org)

Objective: Chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema, is a major cause of morbidity and mortality in lung cancer screening populations and the fourth leading cause of death. Among smokers, 20% develop COPD, so it is vital we identify persons at increased risk. Empirically, the more one smokes, the greater the anticipated degree of emphysema. Using a qualitative visual assessment score, we sought to determine the relationship between pack-years of smoking and the degree of centrilobular emphysema (CLE) in our lung cancer screening program cohort.

Materials and Methods: After we obtained institutional review board approval, the extent of CLE was retrospectively assessed on baseline lung cancer screening CT performed on eligible persons at our institution from November 2013 to July 2016. All screening examinations were performed on either Definition Flash or 64 Fast Care scanners (Siemens Healthcare) using lung cancer screening imaging parameters recommended by the American College of Radiology. Four cardiothoracic staff, one fellow, one resident in the second postgraduate year, and two third-year medical students simultaneously reviewed all studies visually scoring the extent of CLE on a scale of 0–3. A score of 0 (none), indicated no CLE; 1 (mild) indicated CLE involving 25% of the lung; 2 (moderate) indicated CLE involving > 25% but < 50% of the lung; and 3 (severe) indicated CLE involving = 50% of the lung. Smoking history, cumulative pack-years, and demographics were obtained from the lung cancer screening assessment form.

Results: A total of 341 baseline lung cancer screening CTs were reviewed. Of these, 177 were women (mean age, 62 years; range, 50–77 years) and 164 were men (mean age, 62 years; range, 50–76 years). Lung cancer screening was performed on 215 current and 126 former smokers. In total of 19 (6%) screenings had a CLE score of 0; 256 (76%) had a CLE score of 1; 42 (12%) had a CLE score of 2, and 24 (7%) had a CLE score of 3. Among women screened, 10 (6%) had a CLE score of 0; 129 (73%) had a CLE score of 1; 27 (15%) had a CLE score of 2, and 11 (6%) had a CLE score of 3. Among men, nine (6%) had a CLE score of 0; 127 (77%) had a CLE score of 1, 15 (9%) had a CLE score of 2, and 13 (8%) had a CLE score of 3. Of the 215 current smokers, 45 (21%) had a CLE score = 2 (moderate to severe). Of the 126 former smokers, 21 (17%) had a CLE score = 2 (moderate to severe). In screened patients who were 50–54 years old, 16 (76%) had a CLE score of 1 (mild), and four (19%) had a CLE score = 2 (moderate to severe). In patients 55–59 years old, 82 (75%) had a CLE score of 1 (mild), and 21 (19%) had a CLE score = 2 (moderate to severe). In those 60–64 years old, 81 (76%) had a CLE score of 1 (mild) and 19 (18%) had a CLE score = 2 (moderate to severe). In those = 64 years old, 77 (74%) had a CLE score of 1 (mild) and 22 (22%) had a CLE score = 2 (moderate to severe). In persons who had smoked for 40 pack-years or less, 130 (77%) had a CLE score of 1 (mild) and 28 (17%) had a CLE score = 2 (moderate to severe). Of those who had smoked for more than 40 pack-years, 126 (73%) had a CLE score of 1 (mild) and 38 (22%) had a CLE score = 2 (moderate to severe).

Conclusion: Unexpectedly, the CLE score did not increase with increasing pack-years. Additionally, CLE scores did not vary significantly with age, sex, and current smoking status. Other contributing factors including burn time, drag time, age when smoking began, and genetic factors should be considered in lung cancer screening programs to identify high-risk persons.