NUCLEAR MORPHOMETRY IN BREAST-CANCER - THE INFLUENCE OF SAMPLING RULES AND FREEZING OF SAMPLES

We studied nuclear morphometry of human breast cancer with special emp hasis on two sources of variation: freezing prior to fixation and sele ction of measured objects on the basis of different sampling rules. Sa mples of 147 histologically verified invasive breast cancer cases were examined with a computer-based image overlay drawing system. Thirty-e ight of the 147 samples of tissue frozen before embedding in paraffin were analyzed separately. Among the latter we found shrinkage of 35% a nd 46% (depending on the sampling rule) of the nuclear profile area as compared with samples not frozen before the standard tissue processin g. These findings confirm that nuclear morphometry results from frozen and unfrozen tissue are not comparable. Frozen tissue later embedded in paraffin should not be used with prognostication models based on tr aditionally fixed tissue. In morphometry we applied two sampling rules that differed in the criteria used for selecting nuclei for measureme nt. We registered a significant difference in nuclear size and in the variation of nuclear size between the two sampling methods. Of the mor phometric features studied, nuclear area was affected most. Finally, w e examined the two sampling rules in light of the established prognost icators in breast cancer: tumor size, axillary lymph node status, and the Multivariate Prognostic Index (MPI). The two sampling rules result ed in different distributions of morphometric results in the prognosti c groups. Our findings emphasize the significance of the sources of va riation in nuclear morphometry. They also stress the need for well-sta ndardized morphometric methods in predicting the outcome of breast can cer.