Background The Covid-19 pandemic has led to unprecedented disruption to the NHS through increased redeployment of staff, beds, operation theatres and laboratory testing capacity, alongside increased levels of staff health related absences, fatigue and significant changes to patient-GP consultations. Cancer has been impacted in several ways including but not limited to fewer symptomatic presentations at primary care, drop in referrals for cancer testing, screening programmes suspended, and treatments cancelled/postponed. To better understand the impact of the disruption caused in the UK, Macmillan set out to estimate the number of people missing a cancer diagnosis since the start of the pandemic.

Methods The ‘diagnosis-missing’ population was estimated by calculating the difference between observed cancer diagnosis activity and expected cancer diagnosis activity for each month since March 2020. Expected activity was calculated using 2019’s monthly average and weighted by the number of working days in each month. The diagnosis-missing population is calculated independently for each nation utilising diagnosis activity indicators from different datasets: new cancer diagnoses (Rapid Cancer Registration Dataset, England), patients with pathological confirmation of cancer (Cancer Pathology dashboard, Scotland and Patients with Pathology Samples Indicating Cancer report, Northern Ireland) and first definitive cancer treatments at one month lag (Cancer Waiting Times, Wales).

The drop in first cancer treatments in England between March 2020 and September 2021 has been estimated by calculating the difference between the reported number of first cancer treatments (NHS England, 2021) across the above period and 19 months of the 2019 average.

Results As of September 2021, 47,000 people across the UK are estimated to be ‘missing’ a cancer diagnosis as a result of the disruption caused by the pandemic. Recent analysis shows signs of alleviating the cancer backlog in spring 2021 had stalled over the 2021 summer period. Analysis also highlights 6.6% fewer first cancer treatments in England between March 2020 and September 2021 compared to 19 months of the 2019 average.

Conclusion The spread of the Omicron variant and the resultant high levels of staff isolation, and varying restrictions influencing health-seeking behaviour has potentially caused further accumulation of missed diagnoses and delayed treatments over winter 2021/22.Stretched services are likely to see further strain when the ‘missing’ patients do eventually come through the system. Patient clinical outcomes, experiences and longer-term quality of life are at risk of worsening from 2019 standards due to the combination of delayed diagnosis and longer cancer treatment wait times.