Implications from seer data on breast cancer management

From the SEER files of the NCI, 8,587 cases of breast cancer diagnosed in 1975 were analyzed. Of these cases, 5.3% were noninvasive. Of the invasive cancers under 0.5 cm in diameter, 17.2% had positive axillary lymph nodes. Where the physician recorded no palpable axillary lymph nodes, 34.5% were found to be positive.