[COSMOS]PET应用于肺癌的筛查
Positron Emission Tomography in lung cancer screening: Six-year results
Authors: Giulia Veronesi1, Laura Travaini1, Cristiano Rampinelli2, Raffaella Bertolotti3, Lorenzo Spaggiari4, Massimo Bellomi4, Alessandro Pardolesi1, Giovanni Paganelli1
1European Institute of Oncology, Milan/ITALY, 2European Institute of oncology, Milan/ITALY, 3European Insitute of Oncology, Milan/ITALY, 4Università statale di Milano, Milan/ITALY
Background:
Lung cancer computed tomography (CT) screening is a controversial topic. Results from the National Lung Screening Trial showed that low dose CT (LD-CT) can reduce lung cancer mortality by at least 20%. However a critical issue is the high rate of indeterminate lung nodules and false positive cases. The aim of the study was to evaluate the diagnostic accuracy of CT/PET for lung cancer diagnosis in the context of lung cancer screening.
Methods:
Between 2004 and 2005, 5203 asymptomatic high-risk individuals (≥20 pack-years, age ≥50 years) were enrolled to undergo annual LD-CT for 10 years. Nodules ≤5 mm were scheduled for repeat LD-CT a year later. Nodules >5.0≤8.0mm received LD-CT 3-6 months later. Nodules >8.0mm or growing nodules underwent CT-PET. Results from all PET scans performed during the screening workup of COSMOS participants were reviewed. Those performed for suspected collateral disease (pleura, mediastinum, other cancers) were excluded. Outcome was based on the pathological findings for patients who underwent surgery or on findings at follow-up. Outcome was considered negative for those with negative CT findings for at least two years. PET results were visually evaluated by expert radiologists.
Results:
383 nodules in 351 patients were studied by CT/PET. In 5 occasions, PET evaluation was dubious. 197 nodules turned out to be malignant. Overall sensitivity, specificity and accuracy of CT/PET to distinguish between benign and malignant nodules was 64%, 89% and 76% while it was 82%, 92%, 88% when considering only PET scans performed during baseline screening work-up. Diagnostic performance was high (sensitivity 87%, specificity 73%) for nodules larger than 15 mm in their maximum diameter, reaching 98% sensitivity for solid nodules larger than 15 mm. The diagnostic performance of the test was significantly lower for nodules investigated at annual repeat CT compared to baseline CT (p<0.0001, sensitivity ranging from 30 to 71%) and for non-solid compared to solid nodules (p=0.0001; sensitivity 22% for non-solid versus 79% for solid nodules).
Strata | PETs | VN | FN | FP | VP | Sensitivity | Specificity | Accuracy | p-value |
Overall | 378 | 164 | 70 | 21 | 123 | 64% | 89% | 76% | |
Diam <10mm | 145 | 75 | 40 | 4 | 26 | 39% | 95% | 70% | |
Diam 10-15mm | 104 | 51 | 19 | 4 | 30 | 61% | 93% | 78% | |
Diam >15mm | 117 | 30 | 10 | 11 | 66 | 87% | 73% | 82% | 0.06 |
Solid | 263 | 123 | 26 | 16 | 98 | 79% | 88% | 84% | |
Non solid | 48 | 15 | 25 | 1 | 7 | 22% | 94% | 46% | |
Partially solid | 65 | 25 | 19 | 3 | 18 | 49% | 89% | 66% | |
Non/Part solid | 114 | 41 | 44 | 4 | 25 | 36% | 91% | 58% | <0.0001 |
Age <60 | 147 | 64 | 31 | 14 | 38 | 55% | 82% | 69% | |
Age >60 | 231 | 100 | 39 | 7 | 85 | 69% | 93% | 80% | 0.02 |
Inferior lobe | 139 | 69 | 29 | 8 | 33 | 53% | 90% | 73% | |
Superior lobe | 208 | 85 | 33 | 9 | 81 | 71% | 90% | 80% | |
Other location | 30 | 10 | 8 | 3 | 9 | 53% | 77% | 63% | 0.09 |
Left lobe | 148 | 64 | 27 | 8 | 49 | 64% | 89% | 76% | |
Right lobe | 206 | 90 | 35 | 10 | 71 | 67% | 90% | 78% | 0.70 |
Baseline | 148 | 81 | 11 | 7 | 49 | 82% | 92% | 88% | |
2nd year | 57 | 17 | 11 | 3 | 26 | 70% | 85% | 75% | |
3rd year | 62 | 19 | 28 | 3 | 12 | 30% | 86% | 50% | |
4th year | 44 | 10 | 10 | 4 | 20 | 67% | 71% | 68% | |
5th year | 47 | 31 | 6 | 4 | 6 | 50% | 89% | 79% | |
6th year | 20 | 6 | 4 | 0 | 10 | 71% | 100% | 80% | <0.0001 |
Male | 264 | 113 | 44 | 12 | 95 | 68% | 90% | 79% | |
Female | 114 | 51 | 26 | 9 | 28 | 52% | 85% | 69% | 0.05 |
Non/part solid <15mm | 72 | 27 | 34 | 2 | 9 | 21% | 93% | 50% | |
Non/part solid >15mm | 37 | 10 | 9 | 2 | 16 | 64% | 83% | 70% | |
Solid <15mm | 177 | 99 | 25 | 6 | 47 | 65% | 94% | 82% | |
Solid >15mm | 80 | 20 | 1 | 9 | 50 | 98% | 69% | 88% | <0.0001 |
Conclusion:
CT/PET is a highly sensitive test for the differential diagnosis of screening-detected cancer, in particular at baseline CT, for solid nodules and those with a diameter larger than 15mm. Sensitivity of CT/PET for sub-solid nodules is very low suggesting that other diagnostic tests, such as volume doubling time, should be used.
