NHS England chiefs said record numbers were being seen for check-ups before Omicron hit - and despite the current situation cancer was being prioritised.
There have been nearly 50,000 fewer cancer diagnoses across the UK since the start of the pandemic, Macmillan Cancer Support say.
This risks an increase in late-stage diagnoses, reducing survival chances.
Past surveys have suggested people are reluctant to come forward during surges in Covid cases because they did not want to be a burden to the health service.
NHS England said record numbers had had urgent cancer check-ups in November when 246,000 saw a consultant after a referral by a GP - although just over three quarters of these were seen in the target time of two weeks.
NHS England cancer director Dame Cally Palmer added it was vital people did not delay now even though hospitals were under huge strain.
"NHS staff are working hard to ensure that those who are coming forward for checks can be seen quickly so that cancer can be caught at an earlier stage."
She said common symptoms to look out for included diarrhoea that lasts for three weeks or more, new lumps or bumps and unexplained weight loss or fatigue.
Cancer research UK has some useful advice about getting the most out of your doctor appointment and what questions you should ask and what happens during your appointment