MA10.09 Evaluation of the Clinical Utility of the PanCan, EU-NELSON and Lung-RADS Protocols for Management of Screen Detected Lung Nodules at Baseline

Abstract

using CAD, gave the management recommendation using Lung-RADS, and the reading time was recorded. Then the radiologist turned on CAD annotations to accept, reject and add nodule(s). The PanCan nodule risk scores were generated. Nodule management was categorized into 3 groups: I: Scheduled follow-up CT 1yr for those with no or very low risk lung nodules; II: Early recall CT <1 yr; or III: Referral to clinical diagnostic pathway for suspicious malignancy. Result: Radiologist's reading time was shorter in CAD-1 st than Radiologist-1 st arm (9±3 vs. 10±3 minutes, p<0.01). The time saved was greatest for Group I scans (85% of workload) (8±3 vs. 10±3 minutes, p<0.01). In 20/741 (2.7%) participants in CAD-1 st arm, the additional nodule added by the radiologist upgraded the patient's management; 5 of 20 were later confirmed to be malignant. Two of 5 were >3cm masses, the other three included a 19 mm GGO and two solid ones abutting vessels. In 1/645 (0.15%) participants in Radiologist-1 st arm, the additional nodule detected by CAD upgraded the patient's management from Group I to II. Over 31-months of follow-up, 29 cancers (2.1%) have been detected, and 1 of 29 (3.4%), a 5 mm solid nodule in the left lower lobe abutting the fissure and vessels, was missed by both radiologist and CAD. Conclusion: CAD saves radiologist's time in reading large numbers of screening LDCT especially in those with no or very low risk lung nodules. However, reading by experienced radiologist is still needed.

Management of screen-detected lung nodules: A Canadian partnership against cancer guidance document

“…Current applications of nodule malignancy risk prediction models, Lung-RADS or volumetric measurement demonstrate low false positive rates, well under 10%, while retaining high sensitivities. 5,32,49 These false positive rates compare favorably with other cancer screening interventions. Thus, the motivation and need for machine learning solutions may not be as great as initially described unless they can be shown to improve efficiency and accuracy of reading screening LDCTs in prospective randomized trials.…”

“…48 A preliminary study in Canada also suggests the PanCan nodule malignancy risk calculator that uses mean diameter measurement may be more efficient in triaging screenees to a diagnostic pathway than the EU-NELSON volumetric protocol after the baseline screening LDCT with a significantly higher positive predictive value. 49 A randomized trial comparing the clinical utility of volumetric measurement with volume doubling time versus 2-D diameter change to determine the timing of the next imaging study or biopsy and cancer detection rate investigation is needed. Currently, preference can depend on local practice and availability of CAD software until additional data are available.…”

“…58 PanCan recommendation for screenees with no lung nodules or very low malignancy risk lung nodules is supported by other evidence that the 2-year malignancy risk for those without nodules or solid nodules less than 4 mm (33.4 mm 3 ) have low malignancy risk (0.09-0.40%). 5,25,44,49,59,[61][62][63][64][65] Benign findings. Nodules with diffuse, central, laminated or popcorn patterns of calcification or macroscopic fat are benign.…”

“…32,51,52 One of the greatest strengths of the PanCan nodule malignancy risk calculator is identification of individuals with very low risk nodules who may have the next scheduled screening in two years instead of annually. 25,49,[59][60][61] Biennial screening protocol in 80% of low risk screenees instead of annual screening would have a significant impact on resource utilization. 49,61 Further prospective studies are needed to determine if the small subset of screenees without lung nodules or very low risk nodules, which is estimated to be <0.5%, 5,25,44,49,59,[61][62][63][64][65] may benefit from annual instead of biennial screening following the baseline LDCT can be identified.…”

“…A recent study comparing the PanCan, Lung-RADS and NELSON protocols using CAD measured nodule volume for the NELSON protocol instead of calculated volume from diameter showed 12%, 22% and 17% of screeenees would have a recommendation for early recall LDCT or immediate work up with a corresponding cancer diagnosis rate of 12.9%, 6.9% and 9.5%, respectively. 49 At repeat screening rounds, new nodules are not necessarily managed in the same way baseline nodules are managed. New solid nodules are more likely to be malignant compared to baseline at a smaller size.…”