London - The increasing risk of superbugs threatens to make chemotherapy obsolete within a decade, cancer doctors have warned.
Patients rely on antibiotics to help them survive infections after surgery and during chemotherapy as their own immunity is suppressed.
But drug-resistant bacteria mean more are failing to respond to antibiotics, said oncologists.
This means it may soon become too risky to treat cancer patients with chemotherapy as they would be unlikely to be able to fight off any subsequent infections. This could lead to sepsis and death.
Four in ten UK oncologists told a survey that they have seen an increase in drug resistant infections over the past 12 months. Almost three-quarters think this will make some treatments obsolete in ten years.
Nearly half of the 100 specialists questioned believe chemotherapy will become unviable.
The doctors told how five percent of their patients had developed a drug-resistant infection, such as MRSA, in the past year.
They were responding to the survey by the Longitude Prize, a £10-million fund aiming to tackle antibiotic resistance.
It also predicted that 65 000 cancer patients could develop potentially life-threatening drug-resistant infections after surgery in the coming decade. Daniel Berman, from Nesta Challenges, the charity running the fund, said: "Antibiotics are a key part of cancer treatment, many patients simply have to take them as chemotherapy suppresses the immune system. And surgery can lead to infection.
"Oncologists are right to be concerned about growing levels of antibiotic resistance experienced by their patients post-surgery or those undergoing chemotherapy. We cannot change the rules of biology to stop superbugs appearing but we can slow their development and improve infection control and prevention.
"We owe it to all patients to have better real-time diagnostic tests developed and on the market to enable medical practitioners to know when and which antibiotics to prescribe."
Antibiotic resistance is one of the biggest threats to global health and superbugs kill at least 700 000 people each year.
The Longitude Prize will award £10-million to the team of researchers that develops an advanced diagnostic test to quickly identify bacterial infections so the appropriate antibiotic can be given.
Professor Kefah Mokbel, a consultant breast cancer surgeon and chairman at the London Breast Institute, said sepsis is "a potentially life-threatening complication of an infection".
He added: "In chemotherapy patients it can be so devastating that we must start them on IV antibiotics straight away.
"We can’t wait two days or more for microbiology tests. If the patient doesn’t respond to these antibiotics, or if the tests flag up a bacterium that needs a different treatment, we’ll change them.
"We might have to try several antibiotics and so many patients end up having multiple courses, which encourages the development of antibiotic resistance."