The traditional prognostic factors (tumour size, lymph node involvement, receptor status) have now been shown to have limits in terms of prognostic definition. These limits may be partially overcome when parameters exist to determine the extent of tumour biological aggression and the patient's degree of immune response. It is important to clarify these links because they may lead to more precise indications regarding the prognosis and choice of therapy, above all in cases of breast cancer operated with no lymph node involvement. Breast carcinoma is often surrounded by inflammatory cells showing host and tumour interaction. The aim of this study was to evaluate the prognostic value of lymphocyte infiltration in operated breast cancer. The degree of lymphocyte infiltration observed in 56 breast cancer patients was compared with other prognostic factors (tumour size, lymph node status, histological variants, necrotic areas and desmoplastic reaction). This preliminary study allowed the authors to examine the degree of peritumoral lymphocyte density as an important predictive index of overall survival in patients with breast cancer and N-.