Delaying cancer treatment by just a month can put patients at a sharply greater risk of dying, according to research published on Wednesday, the latest to sound the alarm over the Covid-19 pandemic’s impact on other health conditions.

Treatment delays happen in normal times, but the spread of Covid-19 has caused unprecedented disruption to healthcare services.

In a new study published in the “BMJ medical” journal, researchers in the UK and Canada found that delays in treatment – whether for surgery, radiotherapy, or other treatments such as chemotherapy – for seven types of cancers had a significant impact on patient mortality.

“There has never been a systematic attempt to look at all the evidence on what delays in different types of treatment mean for cancer patient outcomes,” said co-author Ajay Aggarwal, a clinical oncologist and Associate Professor at the London School of Hygiene and Tropical Medicine.

“Because we know this is happening to cancer patients during the Covid-19 pandemic it is essential to understand the real impact.”

The study found even a one-month postponement could mean a patient had a six to 13 per cent higher risk of dying. The longer the wait for treatment, the higher the risk.

The authors described the findings, based on dozens of international studies published over the last two decades, as “sobering”.

The research suggests that “for the majority of the major cancers and treatments there is no ‘safe’ treatment delay”, Aggarwal said.

Researchers estimated that a delay in surgery of 12 weeks for all patients with breast cancer – during Covid-19 lockdowns and their aftermath, for example – would, over the course of a year, lead to 1,400 excess deaths in the UK, 6,100 in the US, 700 in Canada, and 500 in Australia.