Two of the most important prognostic indicators for breast cancer are tumor size and extent of axillary lymph node involvement. Data on 24,740 cases recorded in the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute were used to evaluate the breast cancer survival experience in a representative sample of women from the United States. Actuarial (life table) methods were used to investigate the 5-year relative survival rates in cases with known operative/pathologic axillary lymph node status and primary tumor diameter. Survival rates varied from 45.5% for tumor diameters equal to or greater than 5 cm with positive axillary nodes to 96.3% for tumors less than 2 cm and with no involved nodes. The relation between tumor size and lymph node status was investigated in detail.
Tumor diameter and lymph node status were found to act as independent but additive prognostic indicators. As tumor size increased, survival decreased regardless of lymph node status; and as lymph node involvement increased, survival status also decreased regardless of tumor size. A linear relation was found between tumor diameter and the percent of cases with positive lymph node involvement. The results of our analyses suggest that disease progression to distant sites does not occur exclusively via the axillary lymph nodes, but rather that lymph node status serves as an indicator of the tumor's ability to spread.
Cancer 63:181-187, 1989.
UMEROUS STUDIES, done in many countries, have shown the value of using tumor size and nodal status to estimate prognosis in breast cancer. '-I5 These observations are so universally accepted as to form the basis of the TNM staging that is promulgated by the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC). This staging system uses three variables: diameter of the primary lesion (T), number of lymph nodes involved with the metastatic tumor (N), and distant metastatis (T). It is also widely accepted that age, race, histologic type, hormonal receptor status, and a number of other significant variables may influence an individual 's prognosis. 16-23 The relation between tumor size, lymph node status and outcome has been qualitatively known for many years. Fisher et al., in a study of 2578 breast cancer patients, found a relation between size, nodal status and outcome back in 1969. However, these authors concluded that size alone was not as consequential to the patient's From the