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S. Duffy

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    MS 15 - Current Screening Trials, Current Evidence and Screening Algorithms (ID 33)

    • Event: WCLC 2015
    • Type: Mini Symposium
    • Track: Screening and Early Detection
    • Presentations: 1
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      MS15.03 - UKLS Impact of Utilization of Risk Assessment in Trial Selection (ID 1914)

      14:15 - 15:45  |  Author(s): S. Duffy

      • Abstract
      • Presentation

      Future implementation of lung cancer screening programmes will require accurate identification of the population who will benefit the most, to ensure that the benefits outweigh the harms [1]. In the USA, the current criteria for Medicare reimbursement [2], for screening are: age 55 to 77, a smoking history of 30 pack-years or more and smoking within 14 years of entry [3]. However, an in-depth analysis of the NLST showed that there was marked variation in individual risk of lung cancer death, with some screened that had only a low chance of benefit: 20% of participants at lowest risk accounted for only 1% of prevented lung-cancer deaths). [4]Conversely, 88% of the prevented deaths were in the 60% of participants that were at highest risk. The only risk prediction model so far utilised in the recruitment of participants into a CT Lung Cancer Screening RCT, is the LLP~v2~ risk model in the pilot UK lung cancer screening trial (UKLS) [5]. The Liverpool Lung Project (LLP) risk model was based on a case-control study [6]. The LLP~v1~ model utilised conditional logistic regression to develop a model based on factors that were significantly associated with lung cancer (smoking duration, prior diagnosis of pneumonia, occupational exposure to asbestos, prior diagnosis of cancer family history of lung cancer (early onset <60 years) and exposure to asbestosis [6]. The multivariable model was combined with age-standardised incidence data to estimate the absolute risk of developing lung cancer. The discrimination of the LLP was evaluated and demonstrated its predicted benefit for stratifying patients for CT screening by using data from three independent studies from Europe and North America [7]. The LLP~v2~ was used to select subjects with ≥5% risk of developing lung cancer in the next five years for UKLS [8]. This method may improve cost-effectiveness by limiting screening to high-risk individuals. The UKLS approached 247,354 individuals in the two pilot sites, 75,958 people (30.7%) responded positively to the screening invitation. Demographic factors associated with positive response were: higher socioeconomic status, age 56-70 years, and ex-smokers. Those from lower socioeconomic groups and current smokers were less likely to respond. 8,729 (11.5%) positive responders were calculated as high risk of lung cancer. The high risk individuals were more often elderly, current smokers, of lower socioeconomic status and males (2.4x females). 4,055 were randomised into the UKLS. Forty two UKLS participants have been diagnosed with confirmed lung cancer, 34 of these were detected at baseline or three months, giving a baseline prevalence of 1.7% which is significantly higher than that reported by the NLST[9]or NELSON [10]trials. To date, 2.1% of all individuals screened have been diagnosed with lung cancer. 36/42 (85.7%) of the screen-detected cancers were identified at stage 1 or 2. Of those with a confirmed cancer, 17/42 (40.5%) were from the most deprived Index of Multiple Deprivation (IMD) quintile. Figure 1 Figure 1: Percentage of UKLS positive responders (n=75,958) with an LLP risk of >5%, by individual year of age. The positive response rate increased steadily with higher socioeconomic status: 21.7% of individuals in the lowest (most deprived) IMD quintile gave a positive response compared with 39.7% in the highest quintile (p<0.001;) (Figure 2). The proportion of individuals with a high LLP risk score decreased with higher socioeconomic status; ranging from 18.2% in the most deprived quintile to 8.3% in the least deprived quintile (p<0.001;). LLP risk were offset by, the socio-demographic spectrum of the individuals attending the clinic, which was in proportion to that of the original approached sample. People recruited into the UKLS trial therefore spanned all IMD quintiles in roughly equal numbers, including a representative proportion from more deprived postcodes. However, in the high risk sub group of individuals invited for screening, there was a trend towards individuals of higher socioeconomic status being more likely to consent to participate in the trial. Figure 2 Figure 2: Impact of socioeconomic status upon initial response rate (lower line), LLP risk (bars) and trial consent rate (upper line). The demographic and response data from the UKLS pilot trial enable specific recommendations to be made regarding the implementation of any future UK-wide lung LDCT screening programme. Such a programme would need to target those most at risk who may be least likely to take up offers of screening (i.e. the most deprived, current smokers, and the over 70s), and women.

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