[Biomorphological features of "minimal" carcinomas selected from a series of 2077 breast cancer cases].

: Two hundred eighty nine pT1a/pT1b (less than < or = 1 cm in diameter) mammary carcinomas were selected from a series of 2077 consecutive cases of breast carcinoma. When compared with carcinomas of a larger size, they were significantly associated with a lower histological grade (SBR), a lower growth fraction (Ki-67 antigen in less than 20% of neoplastic cells) and a lower number of positive cases (more than 10% of neoplastic cells) as far as p53, c-erbB-2 oncoproteins and EGF-R, as detected by immunohistochemical methods, are concerned. Moreover, a significantly higher number of estrogen and progesterone receptors positive cases (more than 10% of positive cells), and a higher frequency of "other" histotypes with a favourable prognosis, was detected. No difference between pT1a and pT1b cases was noted so that "1 cm size" only stratifies a class with a better prognosis. It is possible that small cases, although invasive, did not undergone sufficient mytotic cycles to produce the sequence of genetic changes that characterize the "no return" phase of breast cancer. A 17% of pT1a and pT1b cases displayed lymph node metastases (mean 26 lymph node/case examined): the number is so high that cautions about simple lumpectomies and about sentinel lymphadenectomy, even in cases of small cancers, are necessary, until a larger number of studies will become available.