The three Peterborough races - 3k, 5k and 10k - will be held on October 24, after being originally planned for June 27. It will still be held at the East of England Showground, with staggered start times still planned, despite the expected lifting of restrictions.
The Stamford race, which was due to be on a muddy course around Burghley House, is no longer listed as an upcoming event. This race was scheduled for June 5, before the government's Covid-19 restrictions will be lifted.
Emily Rowling, Cancer Research UK’s event manager for the region, said: "The truth is, COVID-19 has slowed us down. But we will never stop and we are absolutely determined to continue to create better cancer treatments for tomorrow.
“Every step our scientists take towards beating cancer relies on our supporters. Our Race for Life events are open to all and we’re sending a heart-felt message to everyone to come together in 2021."
Due to the Covid-19 pandemic, Cancer Research UK faces a potential £300 million drop in income over the next three years. Fundraising events were cancelled and shops were only permitted to reopen on April 12.
To sign up for the rescheduled event as a runner or volunteer, visit the Race for Life website.