Hong Kong scientists say they have identified the cancer stem cells responsible for the spread of colorectal cancer to other organs and believe the find will revolutionise treatment.

Current treatments regard all cancer cells as alike, but the Hong Kong University researchers discovered that cancers contain a small number of stem cells responsible for starting and maintaining tumours.

"It will revolutionise the approach to cancer treatment in future," one researcher, Ronnie Poon, told the South China Morning Post.

"If you just target mature cancer cells, you are not targeting the roots of the disease. What the industry needs to work on now is drugs that will target cancer stem cells," the professor of surgery said.

The spread of colorectal cancer to other organs is usually fatal. The cancer is one of the most common in both men and women and kills around 50,000 people a year in the United States, according to the National Cancer Institute.

The ground-breaking research will help doctors to predict patients whose cancers are liable to spread and help development of treatments to specifically target the cancer stem cells, called CD26+, which are more resistant to conventional treatments than more mature cancer cells.

"Identification and charac-terisation of this subpopulation of cancer stem cells will enable us to evaluate for different molecular targeting drugs that can specifically target these cells," researcher Roberta Pang said in a press release on their findings.

"In the long term, it should facilitate the development of more useful, safe and specific drugs that can be used in combination with chemotherapy to completely eradicate the tumour."

Colorectal cancer is the second-most common cause of cancer-related death worldwide. Even with surgical removal of the primary tumour, cancer develops in other organs in more than 50 percent of patients, usually proving fatal despite further aggressive treatment and surgery.