The first GROCTA trial compared 5-year tamoxifen treatment to ten chemotherapy cycles in a group of 504 pre-/post-menopausal, node-positive, ER-positive breast cancer patients. This study also included an arm combining tamoxifen with chemotherapy. Fifteen-year results showed no difference between tamoxifen and tamoxifen plus chemotherapy, while both treatments were significantly superior to chemotherapy alone. A confirmatory study (GROCTA 02) was performed in 244 pre-/perimenopausal patients by comparing 5 years of tamoxifen treatment (plus 2 years of goserelin) to six CMF cycles. No difference has emerged so far between the tamoxifen and CMF arms at a median follow-up time of 62 months. Post-menopausal women were scheduled to receive 3 years of tamoxifen treatment and then to be randomly allocated to further 2 years of tamoxifen or to 2 years of low-dose aminoglutethimide (GROCTA 04B). So far 662 patients have been entered, 375 of whom have been randomized to tamoxifen (n = 188) or aminoglutethimide (n = 187). Preliminary results (median follow-up time 32 months) show no major difference in patients' outcome. A new trial (ITA trial) with a similar design but employing anastrozole in place of aminoglutethimide has been activated in 1998. The GROCTA 03 study investigated the potential superiority of alternating adjuvant chemotherapy over standard CMF. This study, which included 107 node-positive ER-negative pre-menopausal women, was prematurely closed because more patients allocated to the triple alternated chemotherapy appeared to have relapsed and died at the first interim analysis. The use of high-dose chemotherapy (HDC) was explored by the GROCTA 06 trial which included 53 patients with ten or more involved nodes and a maximum age of 55 years. These patients were scheduled to receive three standard CEF cycles followed by one cycle of HDC (cyclophosphamide 5 g/m2; etoposide 1.5 g/m2; cisplatin 150 mg/m2) without any form of bone marrow rescue. This HDC program proved to be feasible but was not superior to CMF-based chemotherapy we had previously employed in a comparable group of patients in previous GROCTA trials. These findings prompted us to explore new HDC programmes with the use of peripheral stem cell support and in addition the possible value of new drugs such as Taxol and vinorelbine. New-generation trials will also explore the value of new prognostic indicators such as tumor proliferative activity, which are prospectively used to allocate patients to different treatment options.