Sydney is a city of health inequity, with yawning disparities in cancer death and diagnosis rates between the rich and the poor, the latest social health data atlas shows.

People living in some of Sydney's most disadvantaged postcodes died potentially avoidable deaths due to cancers at significantly higher rates than their more affluent neighbours, according to the Social Health Atlas of Australia published Saturday.

One in eight women will be diagnosed with breast cancer before the age of 85.

Yet Sydneysiders in wealthier suburbs were more likely diagnosed with a smattering of specific cancers, found the researchers at Torrens University Australia's Public Health Information Development Unit (PHIDU).

Breast cancer was significantly more prevalent in some of the more affluent public health areas (PHAs), with women in the most advantaged postcodes including 26 per cent more likely to be diagnosed than their counterparts in Sydney's more disadvantaged areas, according to the government health data.