Around 10,000 fewer breast cancer patients have started treatment in England over the past year, according Cancer Research UK.
The charity said that around 38,000 fewer people started treatment for all cancers in England in the past year and this number included around 10,600 fewer breast cancer patients.
Breast cancer screening was temporarily put on hold when the COVID-19 pandemic began and this could be one of the reasons for the fall in numbers.
Also, many people are thought to have put off seeking medical treatment, either due to difficulties seeing their GP or concerns that going to hospital might put them at risk of catching COVID-19.
Breast cancer deaths reached a record low during the pandemic but Michelle Mitchell, Cancer Research UK’s chief executive, said this progress could slow.
She said: “These figures are worrying, and we could see progress slow over the coming years as the true effect of the pandemic is revealed.
“The NHS is showing signs of recovery, but a huge effort is still needed to clear the cancer backlog as quickly as possible to help avoid preventable cancer deaths as a consequence of the pandemic.
“Government must make sure there is enough funding for staff, diagnostic equipment and the research needed to improve cancer care across the UK in the long term, so cancer patients are given the best chance of surviving their disease.”
Professor Charles Swanton, Cancer Research UK’s chief clinician, said: “Considering the huge disruption to cancer services, sadly these figures are not surprising. And we’re seeing the impact of effectively pausing breast screening which detects almost a third of breast cancer cases.
“But it’s important to remember that cancer screening is for people without symptoms, so it’s vital that if people notice anything unusual for them, please don’t wait for screening – get in touch with your GP.
“In most cases it won’t be cancer, but if it is, catching it early gives the best chance of survival.”
An NHS spokesperson said: “The NHS is working hard to treat more cancer patients than ever before and the latest figures show that treatment levels are now back to pre-pandemic levels, with more than 200,000 people referred for cancer checks in April following a record high the month before, and more than nine in 10 people started treatment within one month.
“Breast screening services are open with extra clinics put in place and thousands of invites being sent every month, so if you are invited please book your appointment.”