Antibiotics may affect survival in aggressive brain cancer

Researchers have found a possible link between taking antibiotics during glioblastoma cancer treatment and shorter survival.

The study was conducted by researchers at University Hospital Southampton (UHS) and Guy’s and St Thomas’.

The results are now published in the journal Clinical Oncology.

Dr Sean Main, consultant neuro-oncologist at UHS, is first author. He is supported by the UHS Research Leaders Programme.

Aggressive brain cancer

Approximately 40 percent of patients with brain cancer have a glioblastoma tumour. This is a particularly aggressive and difficult to treat form of brain cancer.

Patients diagnosed with glioblastoma are sometimes given an antibiotic. This is given as part of standard treatment, alongside radiotherapy and chemotherapy.

The aim is to help combat a rare form of pneumonia that patients with glioblastoma can have.

Shorter survival with antibiotics

The new research suggests antibiotic treatment can have a negative effect on long term survival rates.

The study involved 373 patients with glioblastoma across both UHS and Guy’s and St Thomas’. It found that patients receiving antibiotics lived for a shorter time than those who did not. This was despite these patients recovering from their infections.

Further testing showed the link between antibiotics and survival rates remained, even after the researchers considered other factors that can affect survival. These include steroid use, tumour characteristics and infection.

Informing future treatment

The research was supported by the Tessa Jowell Brain Cancer Mission's Fellowship Programme. Dr Main is their inaugural fellow, co-funded by the National Institute for Health and Care Research (NIHR) and the Tessa Jowell Foundation.

“For patients with glioblastoma, every opportunity to improve treatment outcomes matters,” he said. “Our study suggests that broad-spectrum antibiotics may have unintended consequences for survival.

“While further research is needed to understand the underlying mechanisms, it highlights the importance of carefully balancing the benefits and possible effects of antibiotic use during treatment.”

Jess Mills is CEO and founder of the Tessa Jowell Foundation.

“People diagnosed with glioblastoma urgently need every possible advantage,” she said.

“This study highlights how even small changes in the way we deliver treatment could make a meaningful difference, and why research that asks difficult questions is so important.

“The Tessa Jowell Foundation is committed to supporting the brilliant clinicians and researchers who are working to improve both the quality and outcomes of care.

“We are delighted to see our inaugural Tessa Jowell Brain Cancer Mission Fellow leading research that has the potential to shape future clinical practice, and ultimately improve the lives of patients and their families.”

Investigating the microbiome's role

Dr Miguel Reis Ferreira is senior author of the paper. He is consultant clinical oncologist at Guy’s and St Thomas’ NHS Foundation Trust. He is also Clinical Lecturer and King’s College London.

“This study highlights how important it is to use antibiotics carefully in patients being treated for brain cancers,” he said.

“It also suggests that the microbiome – the community of bacteria that live in and on our bodies – may play a role in helping patients get the best possible benefit from treatment.

“It’s important to note that this does not mean antibiotics should be withheld from patients who need them, as they remain essential and can be lifesaving. But it does support avoiding unnecessary antibiotic use and choosing more targeted antibiotics wherever possible.”

The team are now exploring whether the gut microbiome may explain the link. This is being done in an ongoing study involving patients treated at King’s College Hospital and Guy’s & St Thomas’.

The hope is to better understand how antibiotics, infections, cancer treatment and the microbiome interact.

This knowledge could ultimately help clinicians personalise care. This could improve outcomes for people living with glioblastoma.