A type of drug that treats depression and migraines could also reduce the risk of bowel cancer, say researchers from Lincoln University.
Tricyclic drugs, which account for almost a third of all prescriptions for antidepressants, cut the risk of bowel cancer by up to 21 per cent, according to a study.
They also help reduce the chance of developing a cancerous tumour called a glioma in the brain or spine by up to 64 per cent.
Around 40,000 people in the UK develop bowel cancer, while 4,800 people are diagnosed with a glioma each year.
The study, from experts at the universities of Nottingham, Warwick and Lincoln, found people had a lower cancer risk the longer they had been on the drugs and if they took them at a higher dose.
Using GP records, the team identified 31,953 cancer cases for the study, published in the British Journal of Cancer.
Analysis showed that people taking tricyclic antidepressants had a much lower risk of glioma and a lower risk of bowel cancer.
However, lung, breast and prostate cancer were largely unaffected by the pills.
The team said the research suggests ‘tricyclics may have potential for prevention of both colorectal cancer and glioma’.
In 2010, 30 per cent of all antidepressant drugs prescribed on the NHS were tricyclic.
Author Dr Tim Bates, from the University of Lincoln, said the side-effects from tricyclic drugs meant they were not suitable for prescribing to everyone.
They are being replaced with newer drugs such as selective serotonin reuptake inhibitors that tend to be easier to go on and come off.
But patients at higher risk of specific cancers could be picked up through DNA screening and possibly given the drugs.
The study, funded by the Medical Research Council, also points to an ‘Achilles heel’ in cancer cells which could provide a basis for developing new treatments.
These could inhibit the growth of cancer cells without harming normal cells.
Any new drug would focus on the mitochondria in cells – the ‘power house’ of a cell.
Dr Bates said: ‘Development of drugs that modulate mitochondrial function may seem counter-intuitive as mitochondria provide the majority of the cell’s energy.
‘But as cancer mitochondria are biochemically different from mitochondria in normal non-cancer cells, they represent an Achilles heel.
‘It is likely this will lead to the development of new drug treatments for a variety of conditions including cancer, Alzheimer’s, diabetes and other disorders.’