Table 3.
Frequency of Positive Screening Results and Positive Predictive Value at T2 Screening, According to Study Group.*
| Variable | Low-Dose Computed Tomography | Chest Radiography | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Confirmed Lung Cancer | Total | PPV† | PPV Range |
Confirmed Lung Cancer | Total | PPV† | PPV Range |
|||||
| yes | no | unknown | yes | no | unknown | |||||||
| number (percent) | percent | number (percent) | percent | |||||||||
| Positive screening result | 211 | 3838 | 5 | 4054 | 5.2 | 4.5–6.0 | 78 | 1094 | 2 | 1174 | 6.7 | 5.4–8.0 |
| New finding | 196 (92.9) | 1622 (42.3) | 4 (80.0) | 1822 (44.9) | 10.8 | 9.4–12.2 | 74 (94.9) | 865 (79.1) | 1 (50.0) | 940 (80.1) | 7.9 | 6.3–9.5 |
| Stable finding | 15 (7.1) | 2216 (57.7) | 1 (20.0) | 2232 (55.1) | 0.7 | 0.4–1.0 | 4 (5.1) | 229 (20.9) | 1 (50.0) | 234 (19.9) | 1.7 | 0.4–3.6 |
| With subsequent biopsy | 206 (97.6) | 107 (2.8) | 0 | 313 (7.7) | 65.8 | 60.2–71.1 | 74 (94.9) | 35 (3.2) | 0 | 109 (9.3) | 67.9 | 59.0–76.3 |
| With noncalcified nodule or mass |
203 (96.2) | 3715 (96.8) | 3 (60.0) | 3921 (96.7) | 5.2 | 4.5–5.9 | 67 (85.9) | 975 (89.1) | 2 (100.0) | 1044 (88.9) | 6.4 | 5.0–8.0 |
| Size of nodule or mass‡ | ||||||||||||
| <4 mm | 0 | 7 (0.2) | 0 | 7 (0.2) | 0 | 0.0–0.0 | 2 (2.6) | 11 (1.0) | 0 | 13 (1.1) | 15.4 | 0.0–37.5 |
| 4–6 mm | 15 (7.1) | 2007 (52.3) | 1 (20.0) | 2023 (49.9) | 0.7 | 0.4–1.1 | 5 (6.4) | 197 (18.0) | 0 | 202 (17.2) | 2.5 | 0.5–4.7 |
| 7–10 mm | 58 (27.5) | 1072 (27.9) | 1 (20.0) | 1131 (27.9) | 5.1 | 4.0–6.4 | 9 (11.5) | 335 (30.6) | 0 | 344 (29.3) | 2.6 | 1.1–4.4 |
| 11–20 mm | 86 (40.8) | 502 (13.1) | 0 | 588 (14.5) | 14.6 | 11.7–17.5 | 22 (28.2) | 263 (24.0) | 0 | 285 (24.3) | 7.7 | 4.9–10.6 |
| 21–30 mm | 23 (10.9) | 77 (2.0) | 0 | 100 (2.5) | 23.0 | 14.1–31.7 | 19 (24.4) | 47 (4.3) | 0 | 66 (5.6) | 28.8 | 18.2–40.0 |
| >30 mm | 20 (9.5) | 41 (1.1) | 1 (20.0) | 62 (1.5) | 32.8 | 21.0–45.1 | 2 (2.6) | 22 (2.0) | 1 (50.0) | 25 (2.1) | 8.3 | 0.0–20.9 |
| Unknown | 1 (0.5) | 9 (0.2) | 0 | 10 (0.2) | 10.0 | 0.0–33.3 | 8 (10.3) | 100 (9.1) | 1 (50.0) | 109 (9.3) | 7.4 | 3.0–12.5 |
| Other findings | ||||||||||||
| Atelectasis, segmental or more extensive |
4 (1.9) | 90 (2.3) | 1 (20.0) | 95 (2.3) | 4.3 | 0.9–8.8 | 3 (3.8) | 21 (1.9) | 0 | 24 (2.0) | 12.5 | 0.0–28.6 |
| Noncalcified hilar or me diastinal adenopathy or mass |
19 (9.0) | 78 (2.0) | 0 | 97 (2.4) | 19.6 | 12.1–28.1 | 7 (9.0) | 33 (3.0) | 0 | 40 (3.4) | 17.5 | 5.8–30.4 |
| Consolidation | 4 (1.9) | 35 (0.9) | 0 | 39 (1.0) | 10.3 | 2.2–20.6 | 2 (2.6) | 34 (3.1) | 0 | 36 (3.1) | 5.6 | 0.0–14.3 |
| Pleural thickening or ef fusion |
15 (7.1) | 278 (7.2) | 1 (20.0) | 294 (7.3) | 5.1 | 2.9–7.9 | 6 (7.7) | 80 (7.3) | 0 | 86 (7.3) | 7.0 | 2.1–12.6 |
*
The cases of confirmed lung cancer do not include the following cancers diagnosed during the T2 study year: 32 in participants who did not undergo screening at T2, 16 in participants with negative results of low-dose CT screening at T2, and 44 in participants with negative results of radiographic screening at T2.
†
PPV is defined as the proportion of confirmed lung cancers among the participants with positive screening tests who had a known lung-cancer status.
‡
Nodule size refers to the diameter of the largest nodule recorded on the screening examination.