A patient with rectal cancer has become the first to have part of their tumour destroyed by ultrasound, say UK doctors.
A team of radiologists, surgeons and oncologists at Hammersmith Hospital in London used high intensity ultrasound to heat up and kill the cancer.
They say the technique will allow faster and more accurate targeting of tumours than conventional treatments.
Hammersmith Hospital will offer the treatment to advanced stage patients.
High intensity focused ultrasound (HIFU) is carried out under general anaesthetic.
The device can treat tumours up to about 40cc volume and can heat the tissue up to 90 degrees centigrade
The first patient to have the procedure has requested anonymity.
They were given a low dose of heat at 70 degrees.
Doctors say they are planning to treat 50 more patients and they will closely monitor them to discover the most effective temperature at which to perform the procedure.
Unlike radiotherapy, HIFU, can be given to a patient a number of times with minimal risk of toxicity.
The study leader, Professor Paul Abel, from Imperial College Healthcare NHS Trust, said: "There is no incision made during the procedure, it's completely non-invasive, so recovery time will be quicker too.
"As this is the first time this procedure has ever been performed for rectal cancer, we need to study a wider group of patients to assess how effective the treatment is and whether it has the potential to be curative or to lengthen a patient's life."
A spokesman for the charity Beating Bowel Cancer said it welcomes "advances to improve the quality of patients' lives and relieve symptoms".
"As this is a world first, we look forward to further studies and results with more patients over a longer period."