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MA03 - Epidemiology, Risk Factors and Screening (ID 374)
- Event: WCLC 2016
- Type: Mini Oral Session
- Track: Epidemiology/Tobacco Control and Cessation/Prevention
- Presentations: 1
MA03.05 - Cost Effectiveness Analysis of CT vs Chest X-Ray (CXR) vs No Screening for Lung Cancer (LC) in the PLCO and NLST Randomized Population Trials (RPTs) (ID 5516)
14:20 - 15:50 | Author(s): J.P.E. Flores
NLST was the first RPT to demonstrate a significant LC mortality reduction, when comparing CT to CXR-screening. Consequently, CT-screening is now being incorporated into clinical practice. Nonetheless, questions about the value of CT-screening remain given costs of CT and workup of false-positives. A prior cost-effectiveness analysis of CT-screening using NLST data concluded that CT was generally cost-effective (NEJM:371,1793,2014). That analysis was performed under the assumption that CXR-screening only added costs without benefit. In an independent analysis of PLCO comparing CXR to no screening, we found that CXR-screening is associated with a highly significant LC survival advantage. This benefit was unrelated to conventional screening biases, including overdiagnosis. As CXR is less expensive than CT with a lower false-positive rate, its cost-effectiveness relative to CT should be assessed. Data from PLCO and NLST allows comparison of no screening, CXR, and CT.
Costs of screening, diagnostic studies, and LC treatment were calculated based on original PLCO and NLST trial data obtained from NCI. These were estimated in 2015 US dollars from the Medicare perspective. Outpatient costs were calculated using the Medicare-2015B fee schedule. Inpatient costs were calculated using a national payment average by assigning a DRG based on procedures performed. Survival data was generated using the Kaplan-Meier method for each study and mean survival was calculated using available data. These estimates were used to calculate incremental cost per life-year gained The NLST-eligible subset of PLCO was also used to facilitate comparison of no screening, CXR, and CT.
Analysis of PLCO data demonstrate that CXR compared to no screening was associated with a gain of 0.0152 life-years per person at an additional cost of $244 per-person for a cost per-life-year gained of $19,175. In the NLST-eligible subset of PLCO, CXR cost an additional $350 with a gain of 0.0262 life-years per-person for a cost-per-life-year gained of $13,377. In NLST, CT compared to CXR cost an additional $1,181 per-person and with a gain of 0.0157 life-years per-person, or $75,180 per-life-year gained. Using the NLST-eligible subset of PLCO for comparison, the ratio for CT compared to no screening was $36,552.
CT-screening is both effective and cost-effective and represents the optimal method of screening for LC. However, the survival advantage associated with CXR-screening in comparison to no screening and relatively low cost make CXR a reasonable alternative to CT-screening, particularly in regions of the world where cost and availability limit access to CT-screening.
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P1.03 - Poster Session with Presenters Present (ID 455)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Radiology/Staging/Screening
- Presentations: 1
- Coordinates: 12/05/2016, 14:30 - 15:45, Hall B (Poster Area)
P1.03-064 - Chest X-Ray (CXR) Screening Improves Lung Cancer (LC) Survival in the Prostate Lung Colon and Ovary (PLCO) Randomized Population Trial (RPT) (ID 5507)
14:30 - 15:45 | Author(s): J.P.E. Flores
The effectiveness of CXR-screening for LC was estimated in the context of performing a cost-effectiveness analysis of LC-screening comparing CT, CXR, and no screening. CXR-screening has long been considered ineffective because no RPT has demonstrated a LC mortality reduction. However, CXR-screening has been shown to produce a significant survival advantage not attributable to overdiagnosis or other screening biases (JCO:20,1973,2002). The lung portion of the PLCO trial, which compared CXR to no screening, reported no LC mortality reduction after 13-years follow-up (JAMA,306,1875,2011). However, that analysis included all LCs diagnosed over 13-years, despite the fact that the active screening period lasted only 3-years. LC survival was not reported. Since screening is exceedingly unlikely to provide any advantage to individuals diagnosed many years after active screening is discontinued, and because sojourn time associated with CXR-screening is estimated to be up to 4 years, we evaluated outcomes of LCs diagnosed within 7-years of randomization in PLCO.
PLCO randomized 77,445 subjects to an experimental group (EG) undergoing a prevalence CXR and 3 annual incidence CXRs and 77,456 others to an unscreened control group (CG). Using Kaplan-Meier methods in the intent-to-screen analysis of PLCO data, LC survival and mortality were calculated for all LCs diagnosed during the 13-year follow-up, as well as those diagnosed within 7 years of randomization. LC incidence and mortality were compared with Fisher’s exact test. Survival was compared with the log-rank test. All p-values are two-sided.
After 13-years, 1,838 and 1,737 lung cancers were detected in EG and CG, respectively (RR=1.06; 95%CI 0.99-1.13; p=0.09). Median survival was 13.2-months vs. 11.5-months, and 5-year survival was 24% vs. 19% in EG and CG respectively (p=0.0008). There were 1,217 and 1,203 LC deaths, indicating no LC mortality reduction (RR=1.01; 95%CI: 0.93-1.09; p=0.77). Within 7-years of randomization, 1,072 and 1,022 lung cancers were detected in EG and CG, respectively (RR=1.05; 95%CI 0.96-1.14; p=0.27). Median survival was 15.4-months vs. 11.5months, and 5-year survival was 27% vs. 18% in EG and CG, respectively (p<0.0001). Among these cases, there were 764 and 811 LC deaths, indicating a trend toward reduced LC mortality that was not statistically significant (RR=0.94; 95%CI:0.85-1.04; p=0.24)
In PLCO, randomization to CXR-screening produced a significant improvement in LC survival. This survival advantage cannot be attributed to any conventional screening bias including overdiagnosis. The benefit is diminished when lung cancers diagnosed well beyond the active screening interval are included in the analysis.