Duration of lead time in screening for lung cancer

Abstract

Background Screening for lung cancer has used chest radiography (CR), low dose computed tomography (LDCT) and sputum cytology (SC). Estimates of the lead time (LT), i.e., the time interval from detection of lung cancer by screening to the development of symptoms, have been derived from longitudinal studies of populations at risk, tumor doubling time (DT), the ratio between its prevalence at the first round of screening and its annual incidence during follow-up, and by probability modeling derived from the results of screening trials. Objective To review and update the estimates of LT of lung cancer. Methods A non-systematic search of the literature for estimates of LT and screening trials. Search of the reference sections of the retrieved papers for additional relevant studies. Calculation of LTs derived from these studies. Results LT since detection by CR was 0.8–1.1 years if derived from longitudinal studies; 0.6–2.1 years if derived from prevalence / incidence ratios; 0.2 years if derived from the average tumor DT; and 0.2–1.0 if derived from probability modeling. LT since detection by LDCT was 1.1–3.5 if derived from prevalence / incidence ratios; 3.9 if derived from DT; and 0.9 if derived from probability modeling. LT since detection of squamous cell cancer by SC in persons with normal CR was 1.3–1.5 if derived from prevalence/incidence ratios; and 2.1 years if derived from the DT of squamous cell cancer. Conclusions Most estimates of the LT yield values of 0.2–1.5 years for detection by CR; of 0.9–3.5 years for detection by LDCT; and about 2 years or less for detection of squamous cell cancer by SC in persons with normal CR. The heterogeneity of the screening trials and methods of derivation may account for the variability of LT estimates.

Risk of developing subsequent primary lung cancer after receiving radiation for breast cancer

“… 10 , 13 Heterogenous studies on lead time, tumor doubling time, and prevalence/incidence ratios in lung cancer cite 2 to 18 months as the average time for development of a lung cancer. 16 This 6-month time period was chosen to exclude early lung cancers after breast cancer diagnosis that would not be plausibly attributable to radiation and is consistent with study designs with similar clinical questions. The follow-up time from initial breast cancer diagnosis to subsequent primary lung cancer diagnosis was calculated by subtracting the year of breast cancer diagnosis to year of lung cancer diagnosis (the SEER database no longer provides the specific month of diagnosis).…”

Evaluating the clinical trends and benefits of low‐dose computed tomography in lung cancer patients

“…The mean lead time afforded to LDCT screen‐detected lung cancer has been previously estimated. 10 We corrected our survival times using methods described by Duffy et al and the average estimated lead times from the National Lung Screening Trial and Dutch–Belgian lung cancer screening trial 11 , 12 (Table S2 ). We fit competing risk regression with these corrected survival times to mitigate survival benefit attributed to lead time (Table S1 ).…”