A delay in cancer treatment of as little as four weeks is associated with increased mortality for a wide range of cancers and treatment modes, a study has found.

Published in the BMJ, the study found that a four week delay in accessing surgical, systemic treatment and radiotherapy was associated with a 10% increase in mortality for surgery, systemic treatment, or radiotherapy for cancers of the bladder, breast, colon, rectum, lung, cervix, and head and neck cancers.

And the mortality risk continues to rise the longer that treatment is delayed, according to the systemic review and meta-analysis by UK and Canadian researchers.

They analysed 34 studies of curative cancer treatment that included outcomes for 1.27 million patients.

For surgery, an increased mortality risk of 6-8% was seen for each four week delay, with examples including colectomy (Hazard Ratio 1.06) and breast surgery (HR 1.08).

The impact was more marked for some radiotherapy and systemic indications, with a 9% and 13% increased risk of death for definitive head and neck radiotherapy and adjuvant systemic treatment for colorectal cancer, respectively

For adjuvant and neoadjuvant systemic treatment the mortality risk associated with treatment delay varied more widely (HR 1.01-1.28).

There were significant associations for bladder neoadjuvant systemic treatment (HR 1.24), breast adjuvant (1.09) and neoadjuvant systemic treatment (1.28), and colon and rectal adjuvant chemotherapy (1.13).

Increases in mortality risk were even greater for treatment delays of eight and 12 weeks. For example, an eight week delay in breast cancer surgery would increase the risk of death by 17% and a 12 week delay would increase the risk by 26%

“Such figures translate into significant population level excess mortality,” the study investigators said.

They gave the example of a surgical delay of 12 weeks for patients with breast cancer for a year, as might be seen during covid-19 lockdown and recovery, which they estimated would lead to 500 excess deaths in Australia.

“These results are sobering and suggest that the survival gained by minimising the time to initiation of treatment is of similar (and perhaps greater) magnitude of benefit as that seen with some novel therapeutic agent,” they wrote

The impact of treatment delay would also extend to local control rates, functional outcomes (eg, continence, swallowing), complications from more extensive treatments because of progression during delays and  quality of life, they said

They said the findings had important policy implications for the prioritisation of cancer treatments during the current COVID-19 pandemic.

For example they noted that some countries have released guidance suggesting that it may be safe to delay some colorectal surgery for up to 12 weeks, they noted.

“Policies focused on minimising system level delays in cancer treatment initiation could improve population level survival outcomes,” they concluded

“Taken as a whole, these results suggest there is an urgent need to reconsider how we organise our cancer services. The prevailing paradigm has been around access to new treatments to improve outcomes, but from a system level, gains in survival might be achieved by prioritising efforts to minimise the time from cancer diagnosis to initiation of treatment from weeks to days.”