Page 21 - Deleware Medical Journal - September/October 2019
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PUBLIC HEALTH
for lung cancer who were randomized to receive three consecutive LDCT scans demonstrated a 20% reduction in lung cancer mortality relative to an equivalent- risk group randomized to receive three consecutive chest radiographies (chest x-rays; CXR).12 LDCT and CXR were performed at one-year intervals, with
after randomization. Participants in the LDCT group showed a 6.7% reduction in death from any cause relative to those in the CXR group.12 The number needed to screen (NNS) with LDCT
to prevent one lung cancer death was 320.12 Both LDCT and CXR detected large proportions of adenocarcinomas and squamous cell carcinomas at stage 1 or stage 2; however, stage at diagnosis was more favorable for LDCT.12 Neither LDCT nor CXR performed well at diagnosing small cell carcinomas at
the early stage.12 An estimated 7.5% of participants randomized to receive LDCT were determined to have a clinically
such as vascular conditions of the heart; this percentage was more than three
times as high in the LDCT group as in
the CXR group (2.1%).12 Kinsinger et al. found that 40.7% of those screened with LDCT were determined to have other chronic conditions such as emphysema, pulmonary abnormalities, and coronary 13 The opportunity
for early diagnosis of additional chronic conditions through LDCT screening, especially among older Delawareans,
will further reduce overall morbidity and mortality and generate substantial cost savings for the state. With the population of Delawareans age 65 and older projected to increase 39.5% from 2020-2050 (from 186,690 to 260,414),14 we must capitalize on opportunities such as LDCT screening to reduce health care spending among our state’s elderly population.
Relative to CXR, LDCT was associated with a higher risk of false positive results.
In the NLST, the rate of positive screening over all three rounds was 24.2% with LDCT; among those with a positive LDCT, 3.6% were determined to have lung cancer. In comparison, the rate of positive screening over all three rounds was 6.9% with CXR; 5.5% of those with
a positive CXR were determined to
have lung cancer.12 A recent study found that 59.7% of individuals screened with LDCT received a positive result while 1.5% of all individuals screened with LDCT ultimately received a lung cancer diagnosis.13 Although LDCT is associated with a high risk of false positives, follow-up care resulting from these
false positives is largely non-invasive. American College of Radiology Imaging Network (ACRIN) guidelines recommend that individuals with indeterminate or positive LDCT results undergo repeat LDCT, limited thin-section CT, or other diagnostic testing at varying intervals based on level of suspicion for lung cancer. The rate of resulting invasive
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