Post-surgical pathological staging and ancillary tests determine the initial treatment of breast cancer. Because change in the structuredness of the cytoplasmic matrix (SCM) of peripheral lymphocytes (as assessed by measurement of fluorescein fluorescence polarization, FFP) has already emerged as diagnostic for breast cancer and an aid to staging in other cancers, testing was carried out in 113 pre-surgical patients to see whether such change could contribute to accurate staging of breast cancer. The FFP test was able to distinguish grouped stages of locoregional disease from metastatic disease but was unable to distinguish between any single locoregional stage and the metastatic stage. Technological improvements now underway may create a role for assessment of SCM changes in breast cancer staging.