Scientists at Swansea University say they have made a breakthrough which could revolutionise prostate cancer treatment.
Researchers at the university's School of Medicine have developed a way of shrinking cancer cells using a harmless strain of salmonella bacteria.
It targets the tumour but leaves healthy tissue unaffected.
The university's Dr Claire Morgan described it as a "game-changer".
The new method would mean patients would require just one dose of the treatment and it could also have implications for the treatment of other forms of cancer.
In the UK more than 47,000 new cases of prostate cancer are diagnosed each year.
It is a disease which claims the life of one man every hour.
But the team at Swansea believe their findings could pave the way for better treatment of the condition.
Their research involved modifying salmonella bacteria, normally associated with food poisoning.
The bacteria was altered to render it harmless and free of side effects.
It was also engineered so it could deliver a drug, a therapeutic molecule, which targeted and reduced the cancer cells.
"We're exploiting a natural system within our cells which enables specific genes to be switched on or off," said Professor Paul Dyson from Swansea University.
"The molecules we deliver with the help of the salmonella trigger, this 'switching off' of the genes: the genes that drive the growth of the tumour.
"This is a completely harmless treatment.
"The salmonella will not cause any disease to any healthy tissue. It will only attack and target the tumour cells."
The cancer cells have no natural defence against the modified strain of bacteria.
Once the cells are attacked they are starved of nutrients so they do not grow.
Meanwhile the bacteria starts producing and releasing its anti-cancer drug in the tumour.
Unlike chemotherapy and radiotherapy, the treatment is non-toxic and targets only the tumour, not healthy tissue.
This means patients would only require one dose of the treatment.
"I do believe this research is a game-changer," explains Dr Claire Morgan from the University's School of Medicine.
"Therapies that currently exist are very toxic and people can become ill and quite resistant to it as well.
"We feel that this could potentially change the way that cancer therapy is delivered."
Using cultured cancer cells in the lab, scientists have proved that prostate tumours shrink when they are exposed to this modified strain of salmonella bacteria.
The next phase of the research will be to test it in pre-clinical trials.
Cancer Research UK has supported that next phase with funding of almost £200,000.
The charity's research engagement manager for Wales, Dr Alexa Bishop said: "This is really exciting.
"In pre-clinical testing if it's shown to be successful it can be applied to other types of cancer, not just prostate cancer.
"The other thing that's really promising is that this potential treatment is non-toxic, which would be a kinder, more effective treatment for cancer in the future."