Physicians at Xijing Hospital in Xi'an, the capital of northwest China's Shaanxi Province, have successfully killed cancer cells by employing a "freezing technique".

A liver cancer patient suffered from a relapse after a surgical operation. Doctors at the hospital said a second operation would severely impair the patient's liver. Doctors at the hospital decided as a last resort to undertake the unusual operation.

Doctors inserted a superconductive knife, two millimeters in diameter, into the tumor emitting high-pressure argon and helium through the knife point. In 60 seconds, the tumor became an ice ball. The temperature dropped to -140 degrees Celsius below zero. All cancer cells were killed.

The operation took only 30 minutes. The patient felt no pain and there was no bleeding. He was discharged from the hospital three days later.

"The therapy is a breakthrough in cancer treatment," said Dou Kefeng, a surgeon in charge of the operation.