The recent literature on prognostic factors in breast cancer was examined with regard to: early or delayed diagnosis, age, menopause, tumour site and size, histological type and grading, involvement of lymph nodes, clinical stage, local recurrence, and distant metastasis. With respect to prognostic factors connected with the response to therapy, the following points were considered: menopause, involvement of lymph nodes, dimensions, clinical stage, free interval, performance and loss of weight, particular sites of metastasis, radiotherapy, oestrogen receptors, prior endocrine management, and certain body fluid parameters (haemoglobin, total lymphocytes, platelets, and white cells, albumin, LDH, SGOT, alkaline phosphatase, blood bilirubin and calcium). Radiotherapy appears to make patients less responsive to subsequent antiblastic treatment, whereas premenopausal status, good psychological and physical efficiency, and prior endocrine management seem to play a positive role in the response to chemotherapy.