Predictive value of flow cytometry for metastatic potential in breast cancer

Breast cancer is the leading malignancy in women in the United States. Tumo r size and nodal metastases have been the most important predictors of pati ent outcome and determinants of treatment; but have also been used to predi ct metastatic potential. This study was undertaken to ascertain the predict ive value of flow cytometry for lymph node or systemic metastases. From 199 4 through 1997, surgical specimens from 106 women who underwent treatment f or invasive breast cancer were reviewed. Epidemiological data, tumor stage, nodal metastases, and flow cytometric data were collected. Analysis of var iance and Student's t test were used to determine whether the presence of n odal metastases or distant metastases correlated with high S phase values a nd aneuploidy. Of the 106 patients studied, the mean age was 57 years; tumo r size consisted of 35 per cent T1, 48 per cent T2, 8 per cent T3, and 9 pe r cent T4. Node status was found in the following distribution: 56 per cent node negative, 38 per cent N1, and 6 per cent N2. Distant metastases were present in four patients. Elevated S phase (defined as >9.0%) was present i n 72 per cent of the population. Fifty-six per cent of these tumors were an euploid. Node-negative patients had an elevated S phase in 66 per cent of c ases, whereas node-positive patients had an elevated S phase in 71 per cent of cases. Neither S phase (P = 0.91) nor DNA index (P = 0.99) proved to be statistically significant in determining axillary node status. Neither did S phase (P = 0.87) nor DNA index (P = 0.48) consistently predict the prese nce of distant metastases. There is no statistical correlation between axil lary node status and flow cytometric data. Breast cancers with high S phase values and aneuploid features do not reliably have axillary nodal metastas es, and this data cannot replace that information provided by axillary node dissection. Synchronous systemic metastatic disease is also not predicted by flow cytometry.