Infiltrating ductal carcinoma of the breast in South Australia. Sizes of primary lesions and histological evidence of axillary nodal metastases.

There are few data available at the community level in Australia to indicate the stages of breast cancers at diagnosis, and whether there is a trend towards earlier detection. Therefore, the tumour diameters and extent of axillary nodal metastases in 434 cases of infiltrating ductal carcinoma, which were reported to the South Australian Central Cancer Registry during a three-year period, were analysed. Approximately 27% of tumours were 1.9 cm or less in diameter, about 48% were in the 2.0 cm to 3.9 cm range, and 25% had a diameter of 4.0 cm or greater. Almost half of the patients (48%) had axillary nodal metastases. The extent of nodal involvement was positively related to size of the primary lesion both in women under 50 years of age and in older women. It is intended that this information will be used in future analyses to discover trends over time in tumour size and nodal involvement at diagnosis.