Patterns of axillary lymphadenopathy demonstrated by mammography: implications for the asymptomatic woman in a breast screening programme.

Carcinoma of the breast is the commonest cause of mortality due to malignancy in women in England and Wales. Mammographic screening, with or without clinical examination, is being used increasingly to detect lesions at an earlier stage. In order to test the claim that an asymptomatic woman with axillary lymph nodes on mammography and no demonstrable underlying carcinoma has a greater than two-fold increased risk of developing subsequent breast cancer, a retrospective analysis was performed on 217 mammograms selected from approximately 40,000 screened women using a cluster sampling technique. A group of women with histologically proven breast carcinoma and two control groups were analysed. The incidence, site and pattern of axillary lymph nodes was compared in the three groups. The relative risk of the asymptomatic woman with axillary lymph nodes developing breast cancer was 1.08 times that of the asymptomatic woman without axillary lymph nodes. From these data we conclude that the presence of lymph nodes does not constitute a risk factor for the development of subsequent ipsilateral mammary cancer and should not influence the assessment of screening mammograms.