The outbreak of the COVID-19 pandemic has resulted in major disruptions to cancer care worldwide, including cancer screening programmes. These interruptions will almost certainly lead to a surge in demand for cancer services that could overwhelm health systems. However, an increased focus on the prevention and early diagnosis of cancer could increase health-system resilience and lessen reliance on resource-intensive interventions, because early stage cancers can be treated more effectively, and cost-efficiently, than advanced stage disease. For this endeavour to succeed, clinical and technological developments in early cancer diagnosis are key.
With screening so important, it is a stark statistic that for lung cancer, screening rates are as low as 6% in at-risk populations compared with 60–80% for breast, colon, or cervical cancer screening, even though early identification through screening can reduce the risk of lung cancer death by 20%. US research shows that nearly two-thirds of newly diagnosed patients with lung cancer do not meet current US Preventive Services Taskforce (USPSTF) criteria for annual lung cancer scans with low-dose CT, but have a similar risk of death to those who meet the criteria. In July, 2020, however, the USPSTF proposed updated recommendations that would nearly double the number of Americans currently offered annual scans by widening the eligibility criteria. The minimum age of inclusion would be reduced by 5 years to include adults aged 50–80 years who have a 20 pack-year smoking history, as opposed to the threshold of 30 pack-years in the current guidance. If approved, the new recommendations would also mean more women and more Black or African-American people would qualify for early screening.
Lung cancer is not a disease that is restricted to smokers. Around 10–15% of patients with lung cancer in the UK have never smoked, while in east Asia, the incidence of lung cancer in non-smokers is about 53% and predominantly occurs in women. With non-smokers not necessarily meeting the criteria for lung cancer screening programmes, understanding the early processes of lung carcinogenesis in non-smokers is necessary to ensure early detection. A study published in Cell in July, 2020, found that lung cancer in non-smokers is molecularly more diverse than lung cancer in smokers. Undertaking genomic, transcriptomic, proteomic, and phosphorylation analyses on 103 samples of early-stage non-small-cell lung cancer (NSCLC) tumours from non-smokers, Chen and colleagues found that tumours in women often had EGFR mutations whereas KRAS and APC gene alterations were more common in men. The study also found a high prevalence of APOBEC mutations in 75% of tumours from female patients younger than 60 years and genetic mutations resulting from exposure to environmental carcinogens, such as air pollution, in tumours from older women. These differences highlight not only a need for new treatments and diagnostic approaches for non-smokers with lung cancer, but also targeted interventions differentiated by sex.
On July 3, 2020, the UK Government together with various charities, announced a £16 million commitment to fund the development of integrated diagnostics to enable earlier detection and diagnosis of oesophageal, bowel, and lung cancer. As we move into the digital era, increased research into screening programmes driven by artificial intelligence (AI) will provide major opportunities to aid earlier diagnosis. Indeed, many such research projects are underway. For example, data from the TRACERx study, showed that AI-driven lung cancer screening combined with next-generation sequencing can map the evolution of lung cancer to predict clinical outcomes at the point of diagnosis. The study showed that patients with NSCLC who had less tumour immune activity were at an increased risk of relapse. Research such as this could transform the way cancer is diagnosed and better select those patients who are most likely to relapse and for whom treatments should be initiated earlier.
Building better resilience into cancer care systems is a clear lesson from COVID-19, and the pandemic provides an important opportunity to re-evaluate and re-configure strategies for global cancer control by directing available resources where they are most likely to have the largest benefit. All stakeholders should redouble their efforts on prevention and early detection to ensure cancer healthcare systems are not stressed beyond breaking point in response to another highly disruptive event in the future.
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