Identifying high risk individuals for targeted lung cancer screening: Independent validation of the PLCO_m2012 risk prediction tool

Abstract

Lung cancer screening with computerised tomography holds promise, but optimising the balance of benefits and harms via selection of a high risk population is critical. PLCO is a logistic regression model based on U.S. data, incorporating sociodemographic and health factors, which predicts 6-year lung cancer risk among ever-smokers, and thus may better predict those who might benefit from screening than criteria based solely on age and smoking history. We aimed to validate the performance of PLCO in predicting lung cancer outcomes in a cohort of Australian smokers. Predicted risk of lung cancer was calculated using PLCO applied to baseline data from 95,882 ever-smokers aged ≥45 years in the 45 and Up Study (2006-2009). Predictions were compared to lung cancer outcomes captured to June 2014 via linkage to population-wide health databases; a total of 1,035 subsequent lung cancer diagnoses were identified. PLCO had good discrimination (area under the receiver-operating-characteristic-curve; AUC 0.80, 95%CI 0.78-0.81) and excellent calibration (mean and 90th percentiles of absolute risk difference between observed and predicted outcomes: 0.006 and 0.016, respectively). Sensitivity (69.4%, 95%CI, 65.6-73.0%) of the PLCO criteria in the 55-74 year age group for predicting lung cancers was greater than that using criteria based on ≥30 pack-years smoking and ≤15 years quit (57.3%, 53.3-61.3%; p < 0.0001), but specificity was lower (72.0%, 71.7-72.4% versus 75.2%, 74.8-75.6%, respectively; p < 0.0001). Targeting high risk people for lung cancer screening using PLCO might improve the balance of benefits versus harms, and cost-effectiveness of lung cancer screening.

Low rates of eligibility for lung cancer screening in patients undergoing computed tomography coronary angiography

“…13,14 Weber et al applied the PLCO m2012 model to the Australian smokers cohort from the 45 and Up Study and reported that it is applicable and generalisable to the Australian population. Only 23 (10%) participants undergoing CTCA were eligible for screening using the PLCO m2012 risk score and an age range of 55-80 years.…”

“…13 Participants with a PLoCO m2012 risk of >1.5% were categorised as high risk and those with a risk of <1.5% were categorised as low risk. 13 Participants with a PLoCO m2012 risk of >1.5% were categorised as high risk and those with a risk of <1.5% were categorised as low risk.…”

“…The PLCO m2012 risk prediction tool has previously been validated in an Australian population. 13 Participants with a PLoCO m2012 risk of >1.5% were categorised as high risk and those with a risk of <1.5% were categorised as low risk.…”

Applying Risk Prediction Models to Optimize Lung Cancer Screening: Current Knowledge, Challenges, and Future Directions

“…In more recent and extensive external validation studies, however, the PLCO M2012 model demonstrated the best performance, with respect to discrimination, calibration, sensitivity, and specificity, although not exceedingly better than the Bach model [45, 46]. In support, a study of >95,000 Australian smokers aged ≥45 years also found that the PLCO M2012 model displayed good calibration and discrimination (AUC, 0.80), and that its performance was largely driven by the main predictors of the Bach model, age and smoking history [47]. …”

Implementing lung cancer screening: baseline results from a community-based ‘Lung Health Check’ pilot in deprived areas of Manchester

“…The service was designed to minimise barriers to participation by reducing travel and increasing convenience/service accessibility. We selected screening participants according to individualised risk, using the PLCO M2012 model, at a 6-year lung cancer risk threshold of ≥1.51% 6. A similar approach was used in the UK Lung Cancer Screening Trial (UKLS), which selected participants based on 5-year risk ≥5% (Liverpool Lung Project model), this was cost-effective and resulted in a high prevalence of lung cancer 7…”