NHS figures show that 106,535 urgent cancer referrals were made by GPs in England in May 2020, down from 200,599 in May 2019 – a fall of 47 per cent.
Health officials are concerned that people with symptoms which could mean they have cancer have stayed away from their GPs for fear of putting strain on services or putting themselves at risk of coronavirus.
Such patients have been urged to contact their family doctors, but GPs warned that hospitals were inappropriately refusing referrals during the pandemic.
For the new study, experts created estimates for deaths based on disruption to cancer services and people avoiding seeking help due to Covid-19.
Researcher Professor Richard Sullivan, from King’s College London, said: “On average, for each avoidable cancer death due to diagnostic delay, 20 years of life will be lost.
“These estimates paint a sobering picture and reflect the many young people who are affected by cancer in the prime of life during their most productive years.”
The authors warned that the true death toll could be far higher once all types of cancer were factored in, together with delays in treatment for those already diagnosed with cancer.
Researchers from the London School of Hygiene and Tropical Medicine in London, who led the research, called for urgent action to tackle the backlog of patients waiting.
An NHS spokesman said: “Hospitals have successfully and quickly cared for patients urgently referred by their GP, with over 94 per cent of cases being investigated within 14 days in May – and the key point remains that anyone with a possible symptom should come forward for a check-up.
“The NHS is taking urgent action to increase the number of tests carried out so that people are seen quickly, and more than 65,000 people have started treatment for cancer during the pandemic.”