Analysis of England’s multicancer early detection screening trial found modest, temporary diagnostic delays in participating regions, adding to concerns about health system effects and the evidence base for population-level blood-based cancer screening.
To evaluate the impact of participation in the NHS-Galleri trial on diagnostic delay rates for suspected head and neck, lung, and upper gastrointestinal cancers.
Key Findings:
Diagnostic delay rates increased from 29% to 30% in participating regions and decreased from 29% to 26% in nonparticipating regions during the first 6 months.
Participation in the trial was associated with an approximately 3-percentage-point increase in diagnostic delay rates.
The estimated increase in delayed referrals during the first year was 9,591.
Average time to diagnostic resolution increased by about 2 days in participating regions.
Interpretation:
Limitations:
Participating regions had greater socioeconomic deprivation and fewer healthcare staff than nonparticipating regions, raising the possibility of residual confounding.
Only 6 months of pretrial data were available to assess baseline trends.
The data could not distinguish between referrals that resulted in cancer diagnosis and those in which cancer was ruled out.
