Selecting variations in extent of surgical procedure for breast cancer

A trol of primary breast cancer must be based upon a thorough knowledge of the early development of this disease.T h e multifocal origin of breast cancer was first proposed about 30 years ago by Foote and Stewart3 in the United States and MuirlO in Scotland.More recently, this concept has been documrnted by the meticulous whole breast histopathologic and radiographic studies of Gallager and Martin.4T h e great majority of breast cancers arise in multicentric areas of the breast parenchyma.There is increasing evidence that most breast cancers exist as silent innocuous in-situ entities for many years-1 to 10 more-before the infiltrating :!tage develops.Once the cancer develops the ability to infiltrate, progression occurs at a more rapid rate and with more lethal consequences.Extension of tumor beyond the breast occurs at a relatively late stage of development through both lymphatic and hematologic channels.Approximately three quarters of the lymphatic drainage of the breast extends into the axillary nodes and one quarter into the ipsilateral internal mammary lymph node chain.13Clinical studies demonstrate an increased risk of spread to the internal mammary nodes as the location of the primary tumor approaches the sternal margin of the breast, as the size of the primary tumor increases, and when axillary nodes are involved with disease16 (Fig. 1).Primary surgical therapy of breast cancer succeeds when the primary tumor and its regional lymph node spread are completely removed before distant metastases are established.T h e scope of the primary operative procediire should be correlated with the extent of