Because neoadjuvant therapy, including preoperative chemotherapy and t
amoxifen, is becoming increasingly common for early breast cancer, it
is desirable to grade tumours before surgery so that the most appropri
ate medical regimen can be selected. We have used a cytological gradin
g system for ductal carcinoma of type not otherwise specified (NOS). W
et-fixed Papanicolaou-stained breast aspirates are examined for the ex
tent of cell dissociation, cell size and uniformity, and the appearanc
e of nucleoli, the nuclear margin, and chromatin. 377 invasive breast
carcinomas were removed after preoperative diagnostic fine-needle aspi
ration. cytology (FNAC) during the 25 months of the study. 286 tumours
were ductal carcinomas NOS on histology. We established three cytolog
ical grades and found that cytological grade corresponded well with th
e established histological grades (Elston's modified Bloom and Richard
son method). All cytological features included in the score were equal
ly important on regression analysis. This study shows that grading of
breast cancer on FNAC is feasible and reproducible. Cytological grade
may substitute for histological grade, so a combination of FNAC and ma
mmography can provide information on tumour type, grade, and size befo
re surgery. We recommend this grading system to centres that use FNAC
for the diagnosis of breast cancers.