LONDON: Believe it or not, if your immune system is strong, your body can keep cancers dormant for years.

According to a team of international researchers some cancers are kept in a state of "equilibrium" for decades, unable to be completely wiped out but also unable to grow, provided the body's immune system is strong, the Daily Mail reported on Monday.

"Proper immune function is now appreciated as another important factor in preventing development of some cancers. We may one day be able to use immunotherapy to artificially induce equilibrium and convert cancer into a chronic, but controllable disease," researcher Dr Mark Smyth of the Peter MacCallum Cancer Centre in Australia was quoted by the daily as saying.

"Further research and clinical validation of this process may also turn established cancers into a chronic condition, similar to other serious diseases that are controlled long-term by taking a medicine," Smyth added.

In fact, the team's findings came from a study of mice which were genetically engineered to develop cancer. According to the findings published in the journal Nature , during the dormant phase, the immune system of the mice reduced a tumour's desire to grow and killed off some cancer cells, but not quickly enough to destroy the tumour.

"Thanks to the animal model we have developed, scientists can now reproduce this condition of tumour dormancy in the laboratory and look directly at cancer cells being held in check by the immune system," co-researcher professor Robert Schreiber at Washington University School of Medicine in the United States was quoted as saying.

Doctors have suspected the existence of tumour "equilibrium" from organ tranplants.

Sometimes cancers appear in donor organs after they have been transplanted into a patient whose immune system has been suppressed.

Professor Cornelius Melief, of the Leiden University Medical Centre in the Netherlands, said: "The startling results demonstrate that considering cancer as a fatal disease is not always appropriate. The implications of this work are far reaching."