Morphometric analysis of differentiation in human breast carcinoma. Tumor grading.

Subjective grading systems suffer from limited reproducibility and do not assign a sufficiently large proportion of patients to the most predictive grades (1 and 3). In 50 cases of stage 1 or stage 2 mammary ductal carcinoma having at least five-year follow-up, we quantitated the proportion of neoplastic cells showing glandular differentiation (DI) or remaining within ducts (IN). Patients who experienced recurrence had significantly less of both DI and IN, and the point at which 10% of neoplastic cells was composed of DI + IN appeared to be predictive for recurrence; ie, 24 recurrences appeared among the 33 patients who had tumors with DI + IN less than 10%, whereas none developed among the 14 patients having tumors with DI + IN greater than 10%. Only three patients could not be classified with this marker. Tumor stage and grade were independent variables. Reproducibility among three observers averaged 95%. The morphometric evaluation can be performed by a technician under the direction of a pathologist.