Morphometry of breast cancer. I. Comparison of the primary tumours and the axillary lymph node metastases.

In 234 patients with primary breast cancer, morphometry was performed of three groups of tumour cells: 1. in the primary tumours without lymph node metastases (PRN); 2. in primary tumours with lymph node metastases (PRP) and; 3. in the axillary lymph node metastatic deposits (LMD). The morphometrical analysis included the cellularity index, the mitotic activity index and seven nuclear features. The highest mitotic activity indices (mean: 14.1) were found in the metastatic deposits (LMD), the lowest (mean: 12.5) in the lymph node negative primary tumours (PRN), whereas the lymph node positive primary tumours (PRP) fell in between (mean: 13.2). The cellularity index shows a similar, though reciprocal, trend. The largest standard deviations of the nuclear features were found in primary tumours with lymph node metastases (PRP). In contrast, the metastatic (LMD) nuclei had the smallest standard deviations. The nuclei of the latter are therefore more regular in size and shape. The differences found are not sufficiently large to distinguish PRN and PRP with an acceptable accuracy (the efficiency, sensitivity or specificity did not exceed 67% irrespective of the decision threshold used). Comparison of primary tumours with lymph node metastases and the metastatic deposits, from the same patients, revealed significant correlations of all morphometric features with the exception of the nuclear shape factor and the nuclear axes ratio. Thus, the nuclei of the metastatic cells in general are identical to the nuclei in the primary tumour from which they arise, but in a subset of patients the metastatic tumour cells have much more monomorphous ellipsoid nuclei. Further investigations are needed to see whether this phenomenon indicates a different malignant course.