Adherence to recommended follow up after a positive lung cancer screening examination is lower in real world settings than in the key clinical trials that led to the approval of national screening programs.
Less than half the patients (43%) invited for low dose lung CT lung screening in a US program received timely follow up after having a positive examination results, according to findings published in JAMA Network Open (link here).
The review of follow rates for 685 individuals who tested positive during lung screening with the North Carolina Lung Screening Registry between 2015 and 2020 found that 292 of them (42.6%) received follow up testing for screen-detected nodules as recommended by the American College of Radiology (ACR) Lung CT Screening Reporting and Data System (Lung-RADS).
Adherence was higher for people with nodules graded as higher risk, with follow up rates of 68% for those with Lung-RADS 4B or 4X (Very suspicious; risk of cancer >15%) for whom Chest CT with/without contrast, PET/CT, and/or tissue sampling depending on probability of cancer are recommended.
For individuals who had Lung-RADS 4A category (Suspicious; risk of cancer 5%-15%) screen detected lesions the adherence rate for recommended LDCTand PET/CT within three months was 49.5%.
For lower risk nodules (Lung-RADS 3, Probably benign; risk of cancer 1%-2%) the adherence rate to recommended repeat LDCT within six months was 30%.
The study investigators said the adherence rates were lower than those of 95% to 88% seen across multiple rounds of screening in the National Lung Screening Trial (NLST) and the Nederlands–Leuvens Longkanker Screenings Onderzoek (NELSON) trials.
However they noted that adherence rates improved if the follow-up time was extended: 80.5% for Lung-RADS 4B or 4X within 62 days; 77.3% for LungRADS 4A within five months, and 68.6% for Lung-RADS within nine months.
Follow up rates also varied according to factors such as smoking status and sex, with smokers less likely to be adherent than people who quit (adjusted Odds Ratio, 0.31; 95% CI, 0.12-0.80) and female participants more likely than males (aOR, 2.82; 95% CI, 1.09-7.28) to be adherent to follow up.
The authors said the findings highlighted the need to better understand the reasons for low follow up rates among some groups of lung screening participants so that strategies can be developed to improve adherence.
They added that the low adherence rates for follow up within recommended timeframes could mean that the benefits seen in key trials of lung screening might not be achieved in real world settings.
The impact of delays in follow-up care of screen-detected nodules is not well known, they noted, but an association has been reported between worse survival and longer interval between the diagnosis of early-stage non–small cell lung cancer (NSCLC) and surgery.
“Therefore, efforts should be made to better define the recommended timeline for follow-up of high-risk screen-detected nodules, … and to understand why recommended follow-up after a positive result are lower in Black individuals, male individuals, and those who currently smoke,” they suggested.
Meanwhile an updated analysis by Australian cancer researchers has estimated that a national lung screening program would be cost effective and reduce cancer deaths by up to 24% if based on the screening parameters and outcomes from international trials such as the NELSON and NLST trials.
The new study by the Daffodil Centre at the university of Sydney, published in the British Journal of Cancer, is said to have helped inform the recommendation to government from the independent Medical Services Advisory Committee (MSAC) supporting the implementation of a targeted national lung cancer screening program, announced earlier this month.
Professor Karen Canfell, Director of the Daffodil Centre, Chair of Cancer Council’s Cancer Screening and Immunisation Committee, and senior author on the study, said Australia was a world leader in cancer screening, yet opportunities for optimal screening outcomes were not always realised.
“Australia is on track to be the first country to eliminate cervical cancer through a combination of immunisation, screening and treatment, and our bowel and breast cancer screening programs are among the world’s best,” Professor Canfell said.
“The overseas NELSON trial (Dutch-Belgian) and National Lung Screening Trial (USA) both showed lives could be saved. However, translating those results will require a focus on optimal implementation to ensure a new lung screening program reaches those who will benefit and that it operates effectively within Australia’s unique health system.
“The key will be for government to continue to work with independent researchers and other stakeholders in considering optimal policy and practice for the early detection of lung cancer, Australia’s leading cause of cancer death.”