Preventative measures may be more effective against cancer than originally thought.

Harvard researchers grouped patients into low or high-risk categories based on four factors; smoking, alcohol use, body mass index and physical activity levels.

Using American national cancer statistics and patient questionnaires, they were were able to calculate and compare carcinoma rates for several different cancers.

Researchers found overall, 20 to 40 per cent of carcinomas and about half of the cancer-related deaths could potentially be prevented by modifying lifestyle. They also saw a drop of 80 to 90 percent in lung cancer rates for patients who pursued a healthier low-risk lifestyle.

The report is published in the journal JAMA Oncology.