Outcomes of Long-term Interval Rescreening with Low-Dose CT for Lung Cancer in Different Risk Cohorts
Menée au Canada auprès de 359 personnes ayant subi, dans le cadre d'un programme international de dépistage du cancer du poumon, une tomographie numérique à faible dose de rayonnements dont les résultats se sont avérés négatifs, cette étude évalue, en fonction du risque initial de développer la maladie (risque faible, modéré ou élevé), l'incidence du cancer du poumon lors de l'examen de dépistage suivant (délai moyen entre deux tomographies de dépistage : 7,6 ans)
Hypothesis : We hypothesize that the incidence of screen-detected lung cancer (LC), in participants with previously negative scans, will be highest in the cohort with the highest baseline risk score.
Methods : Individuals with negative baseline screening results from the Princess Margaret International Early Lung Cancer Action Program prior to 2009 underwent low-dose CT rescreening from 2015 to 2018. Individuals were contacted in order of descending risk, as determined by the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial's PLCOM2012 6-year LC risk-prediction model, and then categorized into three risk cohorts according to their baseline risks. The incidence of LC in each risk cohort was determined and compared. Chi-square testing was used for categorical variables and one-way ANOVA on ranks was used for continuous variables.
Results : Of the 1261 participants we attempted to recontact, 359 participants returned for a rescreening scan (mean of 7.6 years between scans). Participants were divided into low (<2%), moderate (≥2%–<3.5%), and high baseline risk (≥3.5%) cohorts. On average, those in the high-risk cohort compared to the moderate and low-risk cohorts were older (66 vs 62 and 59 years) and had a greater smoking history (54 vs 47 and 29 pack-years). The incidence of cancer in the high-risk cohort was significantly higher than in the moderate-risk cohort (11% vs 1.7%, p=0.002).
Conclusions : There was a significantly higher incidence of LC in the high-risk cohort than in the moderate-risk cohort. The cut-point between the high and moderate-risk was determined to be ≥3.5% 6-year baseline risk.
Journal of Thoracic Oncology , résumé, 2018