A new report by the Australian Institute of Health and Welfare suggests that the number of new cancer cases will surge by more than 30 per cent by 2011 as a result of the ageing of Australia's population.

The projections are based on historical incidence rates and allow for improvements in prevention, detection and treatment over the past 20 years.

The largest projected increases are for the most common cancers - prostate cancer in men and breast cancer in women.

However, the report also suggests the age-standardised incidence rate of cancer is projected to remain stable to 2011

'For most cancers, incidence rates are projected to remain relatively stable, but as the highest incidence rates occur in the older age groups, the expected ageing of the Australian population will lead to large increases in the number of new cases of cancer,' says AIHW report author Ian McDermid.

Overall, the number of new cases of cancers in Australia is projected to increase by 31% from 88,398 in 2001 to around 115,400 in 2011.

'The good news is that incidence rates for many cancers are no longer increasing. This can be attributed partly to the success of anti-smoking and other prevention campaigns and partly to the early detection and treatment of pre-cancerous conditions,' says Mr McDermid.

'If the rate of improvement accelerates rather than simply continues, then we may actually see a lower number of new cases than these current projections indicate.'

The contrast between the slightly declining trend in incidence rates for men and the increasing trend for women is even greater for lung cancer and other smoking-related cancers.

The difference can be attributed to historical smoking rates, which for men peaked around 1945 when nearly three-quarters of men smoked. Lung cancer incidence rates for men peaked in the early 1980s and have since been declining.

Smoking rates for women peaked in the mid 1970s, when almost a third of women smoked.

For women the number of new cases of lung cancer is projected to increase by 38% from 2,891 in 2001 to around 4,000 in 2011.

For men the projected increase is 17% from 5,384 in 2001 to around 6,300 in 2011.

The report has some very good news for women though. Cervical cancer is the only cancer where the number of new cases is projected to decrease, from 735 in 2001 to around 450 in 2011.